The AM Forum

Damn. right off Digikey's site.


Is all electronics headed for this type of quackery? It seems that's where the money is.

high compass? is that like high dudgeon?

And put a fancy Blue wrapper on it and tell them they are solid copper leads, oh, and even though they are polypropylene or some other film cap(ie non polarized), mark a direction on them for signal flow with big arrows. 

Paul

wow, I need to change out the orange drops in my audio amps.

I seem to recall some company making wires and cables for the "high end audio community" and putting arrows on the insulation to indicate the direction of signal flow.

Perhaps the arrow is really a signal to show which lead goes to ground from the outer foil.
Or perhaps it's the other way around.....   Which is groundier than the other?

http://www.thlaudio.com/elnaitme.htm

I must be relieved of my music's vibrational energy.

Rich

teh arrow is to point to where the dummy is that falls for this shit.  ::)

This is bound to win me friends and influence people here....

Dear kind ignoramus hams,

As it turns out, once you wring out a fair amount of the distortion from a given system, and you are using an amplifier that has precious little of the spectra of distortion that happens to not sound good (regardless of absolute level) and happens to also have ZERO loop feedback - which is what many afficionados of high quality audio reproduction do - it turns out that you can actually hear audible and clear differences in not just capacitors.

I know that this seems virtually impossible, and that it appears to be a delusion.
It is not.
I can assure you that it is not.

IF you still have decent hearing, and can hear up to about 14khz or better, and you are not inherently tone deaf, or unable to discern some things auditory (as if you have bad vision, are color blind, to use an analogy) it is trivial to demonstrate this. In fact, its so blatant that many folks who like yourselves were poo-poohing this sort of thing until they ran smack dab up against it had to completely revise their thinking on the subject.

You can likely do a simple experiment yourself on your mid-fi or better speaker system, and make up your own mind about it all. Here's how:
- most average "store bought" speakers use bipolar electrolytic caps (and ferrite or iron core inductors).
- change out the bipolar electrolytics in your speakers for mylar film caps (parallel whatever amount you need to reach the same value if you need to) or better still use polypropylene caps.
- for an even bigger effect, change out at least the tweeter's coil for one you wind yourself using say 14ga magnet wire (they're small, you can handle it) made to the same uH value. IF you want to be a stickler, measure the DCR of the original one, and put a series resistor (preferably a few in parallel, not a single one) that equals the same DCR when added to the much lower DCR of the new one.

IF you have your speakers set up for proper stereo - that's approximately an equal distance apart from the distance you are sitting from them, and they are away from the wall at least a foot or two, and preferably on the same wall, and preferably not obstructed in the direct line of sight, and not in a "live room" (hard floors, hard walls, hard ceiling), THEN you will hear a difference in the spatial presentation (where things seem to be coming from). IF you do not have your speakers set up thusly, the effect will be less clear, and you will only experience whatever tonal change may have taken place. That may still be sufficient, and is so in many cases.

TRY IT.

The difference in a speaker like the venerable Yamaha NS-10 is quite substantial, for example, when this is done.

I know it is hard to imagine that something as small and subtle as a different cap will make a difference, but it does in many situations.

And yes, there are many electrolytics in many mix boards, and albums still sound "good."

Oh, I guarantee that if you take two examples of any decent old tube amp, and swap out the resistors for modern film types, and the caps for modern film types, and improve the filtering on the supply, that the entire character and sound of the amp will also change noticeably. The more of it you do, the more noticeable it becomes. Like a Dyna, Acro, McIntosh, etc... lot's and lot's of people have gone through this very process of doubt and then hearing it for themselves... thousands, maybe tens of thousands now...

Look, they're not all crazy, they're not all wackos, they're not all ignoramuses. Many are highly trained professionals, and many are EE types...

              _-_-bear

PS. "compass" is likely a mistranslation from Japanese or Chinese - likely it really means "frequency". They are saying it provides "smooth sound." That's all.

Yes, not all, which means some are.




And many aren't.


The bug said that!

Yeah!
Now I'm talkin to a bug!!

              _-_-

It's a software bug. How's that for geek humor?   :o

no doubt. but thats because you are changing the bloated wax dripping cat turd looking caps and +300% out of spec resistors that screw up everything in the first place!!!!!!!!  :o :o

Sorry, nice theory Derb.

While there may be some out of spec parts in old gear, this has been done over and over again on gear that is not only not out of spec, it is new.

Assuming you really care at all, try the speaker mod I suggested and report back. I won't be insulted or concerned if you don't hear anything. Chances are you will.

To neatly characterize these continuing criticisms of things "audiophool" here - while some things out there in the audio world are indeed questionable or bogus, most is not - most of the criticism here is roughly equivalent to some "new no-code general running a ricebox" commenting on what's right or wrong with AM.  :o :o

            _-_-WBear2GCR

Motion inside a cap dielectric can give some interesting effects. That is why you don't use XR7 in a class e shunt cap. Some dielectrics are actually piezoelectric.
I found this nailing caps with lightning pulses and called a smart guy to confirm I wasn't crazy.( yea right)
I have to laugh at some of the terms..kind a like the disease a week pill comericals.

As Bear correctly states above, once you have removed the bulk of the grunge and distortion from your system, you will be able to hear more subtle changes that you make to wire, caps etc.  Just like a clicky, chirpy CW TX sounds like crap, you can still tell it's CW, but when you take the distortion out of the signal, and get clean start and stop to the RF wave, you can discern the subtle differences in key performance.  Like an outsider to ham might say, what does it matter which key or paddle you use, it still produces a break/make in current to turn on the TX. They should all sound the same.  Mmmmm.

Anyway, I spent years playing with high end hifi and like many here, started out skeptical, but as the equipment, amps speakers etc improved in my system, so became the ease of which small subtle changes could be heard.

I do love poking fun at certain topics in this forum, but once I a while, I will step up to the truth plate.

Now, where are those gold plated fuses?

Cheers

Paul

I like the silky sound of the ELNA capacitors.

Bear,

sorry, but the vast majority of this "audio compass" & "tessitura"stuff is 100% grade homogenized bullshit. The reason the "old amp" sounds better is because after you put in the new stuff,
the circuit is working correctly for the first time in many years. It has nothing to do with the [insert ass kicking new special revolutionary whatever] they claim. It has to do with the fact that coupling cap you just changed is no longer acting like a resistor
and passing obscene amounts of garbage onto the grid of the next tube in the chain. Or that cathode bias resistor/cap pair you just changed restored a given tubes proper bias for the first time in 40 years.

There's no magic in it. Modern manufacturing methods are very exact and a given component is close enough to another make's in a tube circuit, most of which are highly uncritical of actual component values to not make a whit of difference because of some claim written by a guy in the sales dept. Have you ever worked in the electronics industry for a living? All that shit is written by sales guys, not anyone in the engineering dept. I know that because I made my living making stuff, inspecting stuff, helping engineering teams (never got the degree required to be one myself, but I was the top level aide of 3 guys and chief lab rat for 5 years for a very good team at a heart pacemaker company in Columbia, MD for 5 years) and I know how the game is played. I did time in production, QC, purchasing, customer service, and technical support over 3 different electronic related companies in hmm....21 years. All with only a 2 year degree and a mil spec board soldering/desoldering certificate. Never could handle the math skillz required to actually get a degree. But I did ok for a dumbass.  :P

For almost 2 years, I got paid (not much, but paid nevertheless) to repair antique radios at a little bitty shop in Baltimore that restored Zeniths, Philcos, and all manner of audio tube amps. So I not only have been employed in the modern electronics area, I got to get paid working in what amounted to a radio repair shop straight out of the 1940's.

I'm recounting all this because after all this time, it's occurred to me that I might have had a pretty good working life after all and I'm just trying to find a excuse for some boorish behavior on my part in the past. When I actually recount it all, it's been pretty good and might have a bearing on if something I claim to be true might in fact be true.

One other thing: there are MANY on here that run rings around me as a tech and a troubleshooter - KB3AHE is a good example - he just kicks my ass as a troubleshooter. He's quick and accurate. I wish I had his skillz . But I got one claim to fame I'll claim in my name: my electronic workmanship from soldering SMD's and multi level board repair to tube junk is the best. Thats why I dont fix stuff fast. Good work takes time and planning. the stuff I build or repair to work stays that way 99% of the time.

I dont know why I wrote all this - guess I'm just signifying that I have a reason to believe the way I do on so called 'audiophools', and it's based on employed experience. I don believe they have the techicanal knowledge required to know the differences about anything that goes on inside their gear. They mostly buy pre made stuffed boards with detailed instructions heathkit style if they actually build anything themselves at all. But they dont know the underlying reasons why these sales pitches are baloney.

I am not lumping you in that category. You obviously know something of what you speak. What I cant figure out is why you feel compelled to defend that which is 100% grade A sales dept BS as  "
Why do you? You know better, and I know you do becuase of your posts. Is it just a knee jerk reaction or what?  ??? ???

 

I have an article from March 1996 Speaker Builder magazine, page 42, in which the author tested a large number of 2.2 microfarad capacitors for ESR and D at 3 audio frequencies, and % THD.  The article was translated by John D. Fourdraine from a Netherlands article titled “Kondensatoren” in HiFi Luidsprekers, 1994.

All of the film capacitors tested (with 3V bias ) – polypropylene, polycarbonate, Wondercap, polyethylene, and polyester were all less than 0.001 % THD. 

Many electrolytics were tested, but most do not have a % THD test result listed however.
Philips ordinary electrolytic 63 Volts -  0.025 % THD
Roe ordinary electrolytic 63 Volts -  0.015 % THD
Visaton bipolar smooth foil 35 VAC – 0.012 % THD
Visaton bipolar rough foil 100 V – 0.003 % THD
Wego bipolar, smooth foil, 35 VAC – 0.011 % THD
- - - -

Tantalum electrolytics are supposedly much worse for % THD and were not even considered for the testing. 

I thought that I had some other % THD results for capacitor families here but so far have found nothing else yet.  I will continue looking for real data.

I will defer comment until someone translates that to comprehensible English or French.

Don,

What is "shit" in French?
 
8)

From an article found onthe web:

"Here're some actual R-C filter measurements, taken at 1kHz with
a Krohn-Hite 6200B distortion analyzer, on some random parts.

 R      C    dielectric   dist     comments
 --- ----- ---------- ----- ---------------
 22k 8.2nF polypro  0.002% Panasonic 2% ECQ-P1H822GZ
 22k 8.2nF film        0.003% Phipps & Bird subst. box
 22k 8.2nF ceramic  0.071% CK05 100V MIL jellybean
 160 1uF tantalum   0.046% 50V gum-drop ECS-F1HE105K
 160 0.1uF tantalum 0.040% 50V radial molded Kemet
 160 1uF electrolytic 0.017% 1uF 25V radial
 160 1uF electrolytic 0.053% at 3 kHz, -15dB"

mierde (spelling?)   ;D

Tim said:
I always thought it was "Zug, Zug!"

(http://www.movieprop.com/tvandmovie/reviews/caveman.jpg)

Derb, you've got an idea, and you've got hold of it like a Pit Bull on a kid's arm.  :o
Oops, bad analogy.
I addressed your presumption before. While this might happen, and if it did that would make a correct conclusion, the fact is that you can make these changes to a perfectly good, correctly working and biased amp and hear them. Period.



Yes.


You're misunderstanding what's going on here.

<snip>

Derb, you're misinformed.
Go to http://www.diyaudio.com and read through some of the longer threads in there.
Especially in the solid state section - some of the design chops possessed by these fellows is astounding, same thing in the other sections.

The fellows who buy kits and semi-kits are following in the footsteps of those who have explored the matter rather fully, in most cases. Yes there is the occasional rip-off artist and there are some downright stupid "high-end" products - those are funny, and the exception.


Derb, ELNA is a serious cap company. They know what they are doing.
You can hear caps.
If you do, then you'll know why there is a market for different sounding caps.
Like tires on a car, eh? All the same, or not??

           _-_-bear

On this specific issue I agree with Bear, as I experienced it personally over 50 years ago.  Before I was ten, I was working with dad on a speaker enclosure that had a twelve inch speaker and a small university horn tweeter.  He used a multi-section oil-filled cap to drive the horn tweeter, with a small enough reactance to attenuate the low frequencies.  I tried a similar sized electrolytic, and the highs were muddy and distorted.  Even with two electrolytics connected back-to-back in opposite polarity, the highs were distorted.  We connect an old Dumont 208B scope across the tweeter, and drove the amplifier with an HP 200C oscillator, and we could see the distorted sine wave.  Put back the oil cap in place of the electrolytic, and the waveform was clean.  Seems the electrolytic needs to be charged, or polarized, to function as a capacitor at high frequencies.  This is why we do not use electrolytics for coupling caps where we need to pass a wide range of frequencies faithfully.  I have seen cases where electrolytic coupling caps are used to provide good low-frequency response into a low impedance load, but they are bypassed with paper or mylar caps to pass the hi freqs.  I cannot speak for all the hype about the claims for various caps today, but I do agree that the proper type of cap is needed for given applications, and manufactures cut corners for profits so in these cases we can improve performance by replacing the caps.  Just my two pesos, for what its worth....

Since My callsign was drug into this one earlier, I'll just drop in my 2 cents and run!!

As far as I am concearned the difference between a phile and a phool is simply that a phool will spend large sums of money looking for some kind of holy grail device, after he has allready well passed the "point of diminishing return"

A phile has enough technical expertise to stay within commonly known engineering practices, where a phool will spend large amounts of money for snake oil, audio grade knobs and other mythical cure alls looking for extended bragging rights.

I hope this leaves you with a most excellent tessitura!! ;D ;D

                                                                       the Slab Bacon   

Baco-bits,

I clean my "tessitura" with Brasso or Nev-R-Dull "magic wadding".
...dunno about the rest of ya!!

                    _-_-bear

tessitura


From Cambridge Dictionary: tessitura was not found in the Cambridge Advanced Learner's Dictionary.  Did you spell it correctly? Here are some alternatives...


From Oxford University Press: tes•si•tura /'tes{I}'tj{phon_capu}{shwa}r{shwa}; NAmE 't{phon_capu}r{shwa}/ noun (music) (from Italian) the range of notes that are used in a singing part


From Dictionary.com: tes·si·tu·ra      /ˌtɛsɪˈtʊərə; It. ˌtɛssiˈturɑ/ Pronunciation Key - Show Spelled Pronunciation[tes-i-toor-uh; It. tes-see-too-rah] Pronunciation Key - Show IPA Pronunciation
–noun, plural -tu·ras, -tu·re      /-ˈtʊəreɪ; It. -ˈturɛ/ Pronunciation Key - Show Spelled Pronunciation[-toor-ey; It. -too-re] Pronunciation Key - Show IPA Pronunciation.
the general pitch level or average range of a vocal or instrumental part in a musical composition: an uncomfortably high tessitura.
[Origin: 1890–95; < It: lit., texture < L textūra; see texture]

Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.
American Heritage Dictionary - Cite This Source - Share This
tes·si·tu·ra       (těs'ĭ-tŏŏr'ə)  Pronunciation Key
n.   The prevailing range of a vocal or instrumental part, within which most of the tones lie.

[Italian, from Latin textūra, web, structure; see texture.]



From Merriam-Webster Dictionary: tessitura
One entry found.

Main Entry:
    tes·si·tu·ra Listen to the pronunciation of tessitura
Pronunciation:
    \ˌte-sə-ˈtu̇r-ə\
Function:
    noun
Etymology:
    Italian, literally, texture, from Latin textura
Date:
    1875

: the general range of a melody or voice part; specifically : the part of the register in which most of the tones of a melody or voice part lie


From WordReference.com Dizionario Italiano-Inglese    tessitura:
   
Definition
tessitura: nf   panoply (weaving)
Compound Forms/Forme composte:
tessitura piana      plain weave

      one morning on 75 AM Nick KG2IR, who was an engineer at Harmon Kardon explained exactly why they used certain "Black Beauty" caps in a famous high end amp they desinged. it had something to do with low price and availability. i'll try to remember to have him tell that story again, and record it. it really sets the record straight. it's the truth, and the "audiophillies" ain't gonna like it. Bear- if you make you living off these folks and make happy runs to the bank with their money, well then more power to ya OM! personally i think most of it is hogwash.

      have any of my fellow gunners on AM tried Oxygen Free Copper bullets for handloads yet? do they increase muzzle velocity and energy? do they give more consistent groups? should i cryogenically treat my brass cases before they hit the resizing dies? this could be a new market for metalurgical tomfoolery! plenty of shooters are like audiophillies and will buy about anything claiming to make their irons shoot better. these also are the same folks who couldn't hit a deer six feet in front of them with a 20MM cannon... i like to keep it simple. simple and low tech just works. my 100 year old Mausers hit coffee cans at 100 yards easily, and the ceramic caps i use in my audio chains sound just fine thank you.

I thought the name of the company Nick worked for was Common Hard-on.
And I'll have to agree with some of the others about the "phile and Phool" descriptions.
If you need a piece of test equipment to "see" the distortion, and cannot, on God's green Earth hear a 2dB difference in audio level, then that person is a "phool". Expert engineers can train their ears to hear a 2dB difference in audio. The typical shmoe notices 3dB. The average human hearing cannot detect 1% distortion.
And I'm sure there are some here that have heard many live rock concerts in the early days of distorted sound systems and cannot hear above 7khz. I can still hear 14khz.
Fred

From an article found onthe web:

"Here're some actual R-C filter measurements, taken at 1kHz with
a Krohn-Hite 6200B distortion analyzer, on some random parts.

 R C dielectric dist comments
 --- ----- ---------- ----- ---------------
 22k 8.2nF polypro  0.002% Panasonic 2% ECQ-P1H822GZ
 22k 8.2nF film        0.003% Phipps & Bird subst. box
 22k 8.2nF ceramic  0.071% CK05 100V MIL jellybean
 160 1uF tantalum   0.046% 50V gum-drop ECS-F1HE105K
 160 0.1uF tantalum 0.040% 50V radial molded Kemet
 160 1uF electrolytic 0.017% 1uF 25V radial
 160 1uF electrolytic 0.053% at 3 kHz, -15dB" (http://From an article found onthe web:

"Here're some actual R-C filter measurements, taken at 1kHz with
a Krohn-Hite 6200B distortion analyzer, on some random parts.

 R C dielectric dist comments
 --- ----- ---------- ----- ---------------
 22k 8.2nF polypro  0.002% Panasonic 2% ECQ-P1H822GZ
 22k 8.2nF film        0.003% Phipps & Bird subst. box
 22k 8.2nF ceramic  0.071% CK05 100V MIL jellybean
 160 1uF tantalum   0.046% 50V gum-drop ECS-F1HE105K
 160 0.1uF tantalum 0.040% 50V radial molded Kemet
 160 1uF electrolytic 0.017% 1uF 25V radial
 160 1uF electrolytic 0.053% at 3 kHz, -15dB")

yeah, lets hear the difference in the music. It cant be done. The average persons ear cant tell a difference between .0046% THD and 1% THD. The brain is not a scientific instrument. It's easily PHOOLED by other changes made
that are more obvious to the listener than small amounts of distortion.

Ahhh, but did you ever stop to think that perhaps, instruments can't measure everything we hear, and that ol' THD and IMD and M.O.U.S.E. can't really discern what is going on in the music.  I mean, why do vinyl records sound so much more alive and musical than CDs, when CDs measure damn near perfect? And why do tube amps sound so much more lifelike and less harsh (sorry Bear, haven't heard yours yet) than solid state and SS amps measure near perfect and most tube amps have .5-1.5% THD?

Food for thought.

Soap box mode "OFF"

Paul

At the bottom of this post are 2 links to a 2-part article on capacitors.  This first link is for a whole page of links on audio/capacitors.  The 2-part article is listed on this page also.

http://waltjung.org/Classic_Articles.html

Walter Jung is well-known among circuit design engineers.  He is famous for his book entitled “IC Op-amp Cookbook”, published by Sams.  In the co-authored article “Picking Capacitors”, engineering merges into phoolery territory.

'Picking Capacitors, Part 1',  co-authored with Dick Marsh, was published in Audio, in February of 1980. This two part article examined a number of capacitor types for
performance characteristics relevant within audio applications. 

'Picking Capacitors, Part 2',  co-authored with Dick Marsh, was published in Audio, in March of 1980.

The 2 specific links to the Picking Capacitors articles:

http://waltjung.org/PDFs/Picking_Capacitors_1.pdf

http://waltjung.org/PDFs/Picking_Capacitors_2.pdf

Read and see what you think.

Jung was the op amp guy at National right?
His audio amp design is in in my homebrew RX. I did one slight mod
Man I have not seen that article in years.

]

yeah, lets hear the difference in the music. It cant be done. The average persons ear cant tell a difference between .0046% THD and 1% THD. The brain is not a scientific instrument. It's easily PHOOLED by other changes made
that are more obvious to the listener than small amounts of distortion.
[/quote]

  That's why ACID was created my friend! :)

I am glad someone mentioned the fact that if you cannot hear the difference there is in fact no difference to be heard.  ;) I have to agree on the fact that people will hear what they want to hear or what they expect to hear. I spent 22 years as a commercial broadcast engineer and had to put up with all kinds of prima dona jocks that claimed to be able to hear better than bats. We had one particular fellow that would always complain about the AM off air feed. He would complain that it was either distorted or had poor freq response. He also happened to be the GM's brother in law therefore he knew everything right? ::) My favorite thing was to go behind the equipment rack in the studio and just stand there for a minute or so and then ask "Hey Ken,does that sound any better now?". He would listen hard for a minute and then proclaim all was well and thank me. My reply was almost always "Oh, it was nothing". I was in fact NOT lying was I ?  ;D My point is that he expected to hear a difference therefore he "did" hear a  difference. This went on for a few years. It was easier to just humour him. A good sales pitch can also do wonders for some peoples hearing.

I'm trying to summarize what I have read in this thread. And Yea, the analog vinyl sounded really smooth on the ears and the same with tube amplifiers. The tube distortion was a lot easier to enjoy and the sag from the P.S. added another flavor too.
Transistors and their cousins make a different order of distortion that hurts our ears. Digital music is harsh sounding, and that may be that it is not a perfect sine wave audio. Except, of course for the SACD(?)
I think a lot of what we hear is forced on us from tin eared engineers. I have an extensive collection of 45's that are in reasonable condition and when I play the "remakes" or newer version either from a reprint from the record company or a newer version from the artist, I always hear this nasty audio. And this metallic sound is present from transfers from analog tapes to CD. Apparently, these tin eared engineers (prolly deaf from loud music in their past) add their own touch to the EQ and you get this metallic sound. I have transferred many vinyl cuts directly to a stand alone CD recorder and I do not detect any added coloration to the orginal sound.
I'm happy as a pig in #@it with a noise floor of -70 and a freq response somewhere around 20-17khz.
BTW are we still looking at specs for WOW and FLUTTER????????? HA!!!!! Maybe that's another thread!!!!!!1
My hat is off to those who think they hear the difference in audio going through various types of wire and can discern .004% distortion. I don't think it's brain interference, it's a sales condition that has been ingrained in some of us that follow blindly. Keep spending the money, it will help the economy and keep people in work. Obviously it's a big industry NOW!!
Well, enough chatter from MOP radio. Gotta get that RA250 wired up.
G'day...........................Fred

Fred,

Currently, most mix engineers are told, instructed or otherwise "informed" that they need to add mad amounts of compression to the CDs they master.  Albums and cassettes don't suffer from this malady.

It's a "new" 'loudness war'.  Have your entire track running at full throttle means your music sounds better to the tone deaf kids wearing their ipods, digitizing their music (adding layers of distortion), reamplifying it, etc.  It's been documented on sites like slashdot and others.

Welcome to the new audio  generation.  Loudness, extremeness and .....  Well, you can fill in the third.


--Shane

  That's why ACID was created my friend! :)
[/quote]

Ed,

You are 100% incorrect.

It turns out that the absolute value of distortion, below a reasonable level (<1%) is either audible or not audible depending ONLY upon the spectra of distortion. That means the pattern of higher order distortions.

It has been shown in extremely carefully done scientific research that this is the case. (google Dr. Earl Geddes, if you doubt me)

In practice this means that two amplifiers with wildly different absolute values of distortion can be ajudged "equal" in terms of lack of distortion or in terms of having distortion. It is NOT the absolute value of distortion.

Put it in clear terms, an amp with 0.001% distortion measured can sound like dog poop. Ok?

             _-_-bear

What counts is the spectra of distortion products, not absolute value.
And yes, sagging power supplies usually make solid state gear sound awful on peaks...
although if it is a NAD amp, that's a "feature."  :o


Again, not always - what counts is the spectra of distortion products, not the absolute value (amount) of distortion products.

Digital music is not always harsh sounding.
Cheap implementations, or poor implementations (no matter what the cost) sound not so good.
SACD is not immune to these problems at all - it merely sports a slightly wider bandwidth.
The CD does Sinewaves almost perfectly - it's everything else that it is not so good at!


Absolutely, a majority of "re-issues" have been murdered in the transfer and/or the "re-mastering" process.



You can think whatever you like.
However, if you can still physically hear, I can demonstrate the difference in these things with virtually no difficulty whatsoever. It's completely trivial.
And, again, it is NOT the "0.004% distortion" that we can hear, it is the pattern of distortions that we can detect into minute quantities if they are the sort that we are pre-programmed for noticing!


                _-_-bear

While I agree that the ear (or more precisly, the brain) is easily fooled eg  by masking of distortion products ( Harmonic or IM) by other components of a music or speech signal,  its  easy to pick 1% THD from 0.05% THD in a single 1 khz sine wave .   I wouldn't for a moment consider myself a 'golden ear' , but don't forget, the issue isn't if the average person can hear the difference, its if the trained ear can hear a difference.

Normally  a constant tone is the worst case as distortion % due to clipping  will  be worse at higher levels so if peaks are at 1% distortion, the average level will be lower and the distortion % lower.  However with x-over distiortion the distortion % will be higher as the signal drops. I presume this is why class A amps a becoming more popular.

Now here's a question... If your listening to an AM signal with a 40dB S/N ratio , can you hear/measure any improvement if the transmitter end goes from 1% to 0.1% distortion, bearing in mind that 1% distortion products are 40dB below the main signal  ??

                                                                                         Ian VK3KRI
 

And that the ionosphere, receiver AGC and detector add more than 1% distortion to the signal.

It is sometimes a blessing to be half deaf..........

Ian,

I think that you've got it mostly right. But...

It is not so easy to hear the diff between 1% THD and 0.05% THD, IF the distortion products are of certain harmonic structure.

Put it in a related but different way. Let's call one harmonic structure (that's the distortion products quantified by amplitude vs harmonic number) "sweet" and one "sour". IF the lower THD figure happens to be "sour" and the higher (1%) figure happens to be "sweet" the one that will get identified as having "distortion" is the LOWER of the two!!

Most speakers btw are hovering around or above 1% THD at normal operating levels, fwiw.

                  _-_-bear

I did a bit of an uncontrolled test test on the nearest set of ears available.  With a 1khz tone and introducing different harmonics at various levels,  you're certainly right that there is a significant difference between what levels different harmonics need to be to hear a reasonable difference between 'low' distortion and 'distortion' ie  1khz + a harmonic  . The 5th harmonic was clearly the worst. I could pick between 'clean' and 0.1% distortion ( 0db 1khz + -60db  5 Khz) at the optimum listening level. I say optimum level, as increasing the level made it harder to pick the distortion, and decreasing it also made it harder.   

I presume these differences may be due to the uneven 'flatness' of ears at different SPLs.  Also being unable to pick the distortion at higher levels may be due to distortion produced in my ears masking the 5Khz signal being applied. However I would have sworn that the 1Khz + 5khz signal got 'cleaner' as the volume increased, but that could just be the software in my head compensating for known effects at higher SPLs....


I didn't try combinations or try to judge what sounded 'sweeter' but I'm prepared to believe that a higher measured level of a particular harmonics may sound better than a lower measured level of other harmonics,  however iI'd still say that anything with 1% of any combination is going to be noticably 'wrong'


  Aint Psycho-Acoustics facinating !
                                                                           Ian VK3KRI

Hey Ian!

Heh, nice tests!

I think that much depends on what you use for your "test signal" if it is "music" and not a steady state tone, the ability to hear that 1% "distortion" signal changes significantly.

Another problem is that the thing playing the signal back introduces its own distortion products that vary in a non-linear fashion with respect to frequency and level. Tweeters are notorious for be non-linear and having level thresholds beyond which distortions become way more significant.

The addition of certain harmonics to that 5th alone may serve to mask the existence of the solo 5th as the level goes up too...

There was one very well known manufacturer of speakers whose 'claim to fame' was that they could reproduce a bona fide square wave at 1kHz. They could. (on axis) But the achilles heal for them was the tweeter! It was ok fine at levels below 100dB, but above that it completely ran out of 'headroom' and started to go non-linear. Of course that did not show up in the 'tests' or 'specs' that the manufacturer or the reviewers published!

               _-_-bear

I recall back in the 50's seeing a demonstration of a "plasma tweeter".  The thing generated an arc that was modulated with the audio signal.  You could see the blue discharge because the case that contained the arc was made of glass or quartz.  I seem to remember that it sounded pretty good.

It was supposed to eliminate the problems with tweeters attributed to the inertia of mechanical moving parts.  The arc itself delivered the sound.

Yeah Don,

That was likely the Ionofane or Ionovac.

There are/were many other "plasma" tweeters and speakers.
The king of all was the Hill Plasmatronic. Google it.

Today there are still a number of plasma speakers, the downside for most of them is twofold, first the plasma makes a small but discernable hiss, and they generally require a horn to match to the air.

          _-_-bear

Found a construction article.  It even uses hollow state technology.  Basically a Tesla coil operating @ 10 mHz.  A real rfi generator, and there is a warning about the noxious gasses it gives off (especially while reproducing the audio from a medium wave political talk-show  ;) )

http://www.angelfire.com/electronic/cwillis/tweeter.html

I once heard a tale about when the old VOA transmitter site in Mason, OH lost an antenna wire on their big array.  The transmitter was on the air when a support cable or insulator broke.  As the wire separated, it left a tremendous rf arc for a brief instant, caused by tens of kilowatts of modulated AM.  Supposedly, the modulation was clearly audible for miles.

That must have been the world's largest plasma speaker ever.

Don said:
There's an AMer out of Kingston, NC, (name & call escape me now), who used to work for the VOA down there. He too said that when an insulator on the feed-line would crack, you could hear, (and see) the modulation. He said that the insulators would explode soon after in a display of sparks.

W4KBQ?

That be him Steve!

Yeah Don,

There are quite a few DIYers sites on this and more sophisticated units.

This guy is typical:

DISADVANTAGES
-Can start fires
-Arc is a veritable nitric acid factory; must be in    ventilated area
-Extremely inefficient
-Causes RF interference
-Multiple HV voltages required

Nitric acid? Really? I mean maybe, but that's the first I've heard of it.
How about Ozone.

and "Causes RF interference"
Yeah, because you didn't bother to put a grounded screen around it? Duh.

And, he is running on an illegal frequency. They have to be run on 27.xxMhz. at least in the USA, the freq assigned for these various home RF generating things.

If you do a google you can find the Magnat tweeter from Germany and although I can't recall the name at the moment there is a current production horn loaded unit also from Germany that is beautifully built.

Yes, the ISM band (industrial-scientific-medical).  Our old 11m band, that had to accept interference from those devices.  Later became CB.

An old good-buddy rig would make a cheap, readily available, ready-to-go rf exciter for the device.

Woooo, you guys are stirring the ol' memory bank. I HAD a set of those tweeters, sort of a hammer tone blue paint finish, like the door on a GE 250 watt TX.  Horn loaded, seperate power supplies...way cool.  Not much good below about 8-10KC IIRC.

Anyone have the Dayton Wright pre-preamp?  Many dozens of xstrs all paralelled to make a really low Z moving coil preamp.
How about the old Quad seat back ESL speakers?

Cool stuff

Paul

Right, and a constant hiss... if you still had any HF hearing left...

The Dayton-Wright preamp used a standard technique for gettin lower noise out of devices - works for toobes too!

The Quad ESL is to this very day an outstanding performer. The designer Peter Walker really knew his stuff. The limitation of the Quad 57 is output level and bass, but the rest is almost as good as you can get even today!

              _-_-bear

a review of this tube type car stereo amplifier:
http://milbert.com/bam235ab

The critic writes:
"...The sound of this amplifier is exceptional, far beyond anything I expected from a state-of-the-art car stereo. How can I describe the sound? With shrieks and tears and screams."

- This is the kind of claptrap I find humorous.. Maybe he stuck his finger into the amp and was describing the sounds he made.

The unique thing is that the tubes drive a mosfet buck converter to convert their high-Z signal to low-Z to run the speakers. What good is that? no iron!! In defense of the amp, it does have "Auto-Plasma-Bias ™"

I did not see a mention of the mosfet buck converter... did I miss it?
Says: "10 tubes no transistors..."

Depending on how (if?) they did the above trick, it could be a violation of a patent by David Berning - although I doubt that they are as clever as Berning is, or else his patent expired.

                          _-_-bear

I thought it was the Berning design, recalling the schematic in the patent. Maybe I have the wrong amp cited. I've read that the BaM is the 12VDC operated version of the Berning EA-230.

http://www.davidberning.com/products/qz

notice the voltage warning on the PC board..

So, are they the same? There was a picture of the Milbert amp with the cover off, but don't see it now. I believe it had the two HF output transformers, could have been looking at the EA-230, but did not see any large plate transformer which would be expected in a home stereo amp.

Could the Milbert be just a parallel set of totem pole tubes? We've seen that design for decades as the transformerless amp with three 6080's or 6AS7's and a couple of voltage doublers operating right of the 120V line.
http://k-amps.8m.com/cgi-bin/i/PowerAmps/Vacuum/6AS7OTL.gif

Another of Berning's patents seems to copy the old screen-driven class B 807 modulator from the ARRL handbook. Probably sounds better though.
http://www.davidberning.com/technology/patent3995226


In any case it was the review I was citing for amusement. the shrieking and screaming.. too funny.

Dunno I didn't see much on the Milbert page/site... did I miss it??
Where?

The Berning design is clever, but not without some issues regarding the lag of the switching supply vs the input signal to the upper tube...

And, for $29 grand, I think I want a cleaner, better built and laid out implementation...


                 _-_-bear

Here's an article on a full range flame loudspeaker.  I remember mention of same in an old Audio Cyclopedia, but this article has a lot mroe detail.

http://www.4x4pride.org/Flame/Docs/FlameAmp/FlameAmp.html

I've always wanted to load some saboted shotgun shells with aerodynamic machined steel sabots tipped with a bit of tool steel. Alas, I cannot get depleted uranium. I think maybe for po folks, drilling the center of the lead slug and fixing a ball bearing could improve hitting power. For the rifles, there is always steel core ammo. Hard to get (or costly) now. Once upon a time, there was a kind of shotgun ammo called "Blammo". Had a primer in each end. One must protect one's costly AM station.
check this, completely different  - http://www.youtube.com/watch?v=xNPGvPa9NeQ&NR=1

But back to the capacitors - I try to use plastic 'brick' (poly whatever -no electrolytics) and old oil-filled caps whenever possible when doing coupling or bypassing in audio amplifiers and loudspeakers, respectively. That goes for air core coils in crossovers too. I will use orange drops and look-alikes as well and I like their performance just fine in my audio amplifiers. I believe that using a higher voltage plastic or otherwise monolithic capacitor (like 2x-3x the required value) improves the performance, but I cannot prove it.

It is true that putting better components in a system improves the fidelity. There are white papers concerning capacitor selection for ADSL modems that dig into this in detail, even differentiating between different constructions and materials of otherwise identical-seeming monolithic capacitors, and while DSL techniqies are not audio, they are extremely demaning of linearity and symmetry to keep the data rate high. One thing noted was that the best performance seemed to come from the more costly capacitors.

For radio, it comes down to the bottom line, that on the other end of the transmission, after your signal is detected and goes though whatever electrolytics, ricebox DSP, and snazzy 2-way speaker with 6" woofer and 1" dome tweeter the other guy is listening with, he will not hear or measure the difference. There's nothing wrong with using better quality parts on one's TX end, as long as one understands that the point of diminishing return has been passed once the signal leaves the antenna. Anything more is grape nuts and fruit.

Are those alleged subtle and minuscule improvements resulting from such things as silk dielectric capacitors, oxygen-free copper wire, gold-plated connectors, $600 power cords, high-end speaker cable and other questionable-but-expensive audiophoolery, supposed to actually make the music-listening experience more enjoyable, or is this simply to satisfy the desire of a hobbyist cult to gain a little more "perfection" in reproduction, whether real or imagined?

A noteworthy analogy lies within the amateur radio AM community.  We may take pride that our AM transmitters are capable of transmitting an undistorted frequency response at 100% modulation that goes down to 30 Hz or lower, and spend many hours experimenting and modifying our rigs to achieve that goal.  In reality, for voice transmission, undistorted low end down to maybe 80 Hz is more than sufficient for near-perfect voice  reproduction.  The only benefit from undistorted 20 Hz capability would be for music reproduction, which is not legal to transmit via amateur radio.  We work towards this goal solely for the sake of pride of accomplishment, since it will unlikely make an iota of improvement to what our audio actually sounds like at the other end of a QSO, except for incidental improvements to the audio response and distortion characteristics that would likely accompany our careful and prolonged efforts.

Many of the UTC Linear Standard series transformers tout frequency responses down to 7 Hz.  The fine print in the catalogues explains that for distortion-free low end, you need the response to be essentially flat down to about one third the lowest frequency the transformer is actually expected to handle.  So, for distortion-free voice response down to 80 Hz, this implies that the transformers and other components in the modulator need to be flat down to about 26 Hz.  Many converted broadcast rigs, or homebrew rigs constructed from broadcast components should be capable of going down to at least 30~, but I doubt that many of us have a flat response all way down to 7 Hz.

OTOH, doesn't this imply that with "communications grade" audio that has all those "useless lows" sharply cut off below 300 Hz, that everything below about 900 Hz is going to sound like crap?

Don,

The stuff has an effect.
Some is bogus, but really not all that much...

The only questions are:
- is the effect good?
- is it worth the money?
- can you hear it?
- and do you care?

Otherwise it is just fancy art/sculpture for your room...

                        _-_-bear

Hope this helps:

http://gboers.xs4all.nl/daisy/home/g3/139/measure/capacitor-comparison.html

          _-_-

AudioPhiles kill me...I used to be one (it was a very expensive hobby).  My college roommate was much more serious about the hobby than me.  I have fond memories of him trying to drive his flat ribbon speakers with a woefully underpowered Carver amp that made all the lights in our apartment go dim.  Many audiophiles spend 100s of thousands of dollars in pursuit of the perfect "live" concert hall sound.  My opinion is that it would be cheaper for them to go to concert halls on a regular basis.  What I find the most amazing though is the same people that will pay 2K or better for monster cables usually won't spend a penny remodeling their home for improved acoustic response.  There are exceptions to this rule but they tend to be rare.  I guess we all need something to spend our money on.  I'll stick to boatanchors for now.

Oh heck no. what we did in the lab was measurable science. No snake oil, only good parts from major manufacturers with fully documented specifications and guaranted performance.

Let's see this Disputed:

http://members.aol.com/sbench102/caps.html

Steve Bench, by the way, is a competent audio designer. Zero Bullshit on his pages, although he does cater to the audiophool types with this No R no C designs-Which, by the way, were done just to prove a point, not to specifically eliminate anything.

Now, do I believe in the "Magic Capacitors"? No, nothing is magic. But some types of capacitors are better suited to different services. I certainly don't use my Sr-Ti doorknob caps as DC blocking caps in a transmitter, but rather in the Nitrogen laser sitting on the bench across the room...

Steve Bench's tests that you linked show some things, and not others.
SInce he was not on axis with his camera, and it appears to be a non-flat CRT, it's really difficult to compare visually what he tested.

I'd think that there needs to be some expansion, or magnification of the curves, perhaps an overlay to visually see some differences.

Also he used rather LF for testing, not sure that is optimal for revealing cap diffs...

Regardless, there have been some other tests that perhaps are more telling...

In most ham applications, it is all moot...

            _-_-bear

Listen to Capacitor Girl - she knows...
http://www.oldsoundequipment.com/capacitor%20girl.html

Mike WU2D

she'd be OK if she'd trim those nails! They look like big square chisels!

Speaking of capacitors and more;

Do you know what happens when distance between plates change?

Do you know about repulsion and attraction of plates under a voltage?

Do you know about mechanical resonances in capacitors?

Do you know about change of dielectric properties mechanically and electrically?

If at least you answered "Yes" on one of my questions above, why you don't believe that capacitors add specific distortions and character of them depends on how particular capacitor was made, and what materials were used?

Now, do you know that current heats a conductor?

Do you know that heat changes resistance of conductors?

Do you believe now that resistors add distortions?

I like the Battery Girls at Dayton better than this Capacitor Girl.

Might this be phoolish? http://www.cnet.com/8301-13645_1-9866428-47.html

well yes.

Way overprices ugly carp.

Doubtless sounds big though...

I like the idea of a 4k pixel projector... I'll take one of them...

Note that Steve Guttenberg the former actor gets to get paid to write this stuff.
Wonder why I can't get a gig like that??

              _-_-

It is foolish.

Alignment of speakers is brainless.

Here is my setup, to compare.

Woofers on the floor made of solid concrete; Alpine SWR1242 drivers are used. I take 40-200 Hz frequency range from them (36 Hz Fs, sealed boxes -- no mechanical resonances used for equalization). Volume inside is damped by memory foam glued to concrete.

Stereo speakers made as line arrays. As the result, no "sweet spot" because line arrays fire cylindrical wave, i.e. horizontal dispersion is wide, vertical directivity is narrow. Also, reflections from floor and ceiling are minimal. Each side uses 8 cannibalized Infinity Reference 4" speakers (with tweeters removed). For tweeters each side contains 16 Fostex speakers made for notebooks.
Center channel contains 2 Infinity Reference 6.5" speakers, also cannibalized (tweeters removed). For tweeters I used array of 64 speakers made for cellphones.
Since left side is close to the wall I put there a pillow made of memory foam and covered it by a flag with my family coat of arms.
2 rear speakers are again Infinity Reference 6.5", wall between them is covered as well by a memory foam.
For effect channels I use an ordinary Marantz 7200 amp, for stereo I use a tube amp I built with 4x6L6 per channel (I take 50W from each channel only). The amp has stabilized screen grid voltage (lowered for better linearity) and works in class A.

(http://wavebourn.com/images/audio/WavebournHTF.gif)
(http://wavebourn.com/images/audio/WavebournHTR.gif)

I forgot to mention my subwoofer: it is a concrete horn under the floor, with 2 12" Pioneer drivers.
I take from it  frequencies below 40 Hz. It is made horizontally, curved up and opens to the room through a big went hole.
A wall above contains a fake door, made of 2" plywood, coveded by linoleum, memory foam, and vinyl.
As the result, I got very good and clear sound image, using few properly designed and placed speakers.

(http://wavebourn.com/images/domeg/sub_mouth.gif)

Does anyone recall the story that came out a couple months ago - there a room full of audiophiles/phools was unable to distinguish between speakers connected with monstercable and coat hanger wire, in a double blind test.
I'll agree that different capacitors CAN make an audible difference in your audio equipment.  BUT there reaches a point where the differences are due to the power of suggestion - which is what the ELNA silky capacitor advert is all about.

Yes, power of suggestion is the key in audiophilery. Most remarkable is a "Break-In" suggestion: they program each other to start hearing differences at the certain moment. And it works! Like it works when somebody is programmed to start loosing weight at certain moment, etc...

Stupid rhetorical question: did you bother to follow the link on capacitors that I posted a little bit back in this thread?

Wavebourn: ur a smart fellow, and have done some good things - although painting 40's vintage bakelite radios is not high on my list - but it is a mistake to judge things of this sort unless your point of reference is sufficiently broad and includes both a technically astute reference and personal experience coupled with the ability to hear well. And, if by "alignment" you mean "time alignment" (tm Long Associates), then you are incorrect - it does matter.

Everyone: As far as that stupid published "test" using coat hangers?
Well that's about as smart as a test of ham recievers in an environment that is high in noise, like an industrial park. What would such a test tell you about the recievers? Maybe how the noise blankers work? Or how about a test of receivers with really bad antennas connected, or on a day when the bands were dead? Yep, sure enough, can't tell much difference between them? Duh.

Ok, let's go back and revist the race car analogy.
You gonna spend a few grand on a tire for your car?
No?
Betcha will if ur runing in Indy or IROC.
Guess tires don't matter on a car?
How about they matter MORE the higher the performance level required??
At lower levels of performance, the differences are meaningless, or much much less significant or of little interest.
Same thing in audio.

Sure there is BS in audio, just like in other areas - but that does not mean that there are NO DIFFERENCES or that caps, resistors or wires are all the same.

Figure it out already.

             _-_-

The idea of an analogy is that it be analogous to the instant topic.

What is the audio equivalent "run[n]ing in Indy or IROC"? You're talking about things that don't apply to the home consumer (who make up the entirety of the audiophool market).

What units are used to measure higher or lower "levels of performance" in either the auto or audio industry? If there are none, how does one make such a determination?


...nor does it mean that every perceived difference in audio perfomance is never BS.


Stop being abusive, Bear. That's why nobody listens to you when you get all wrapped around the axles whenever someone suggests something which has nothing to do with you or your work may be more audiophoolery than good audio practice.

Stop reacting to anybody and everybody's doubts about some given claim of audio goodness by some third party as a personal attack against you, already.

--Thom
Killer Audio One Zero Gravity Copper

What are you talking about?  How can the required performance level of a set of speakers (or any other audio apparatus for that matter) be any higher than when a group of people, claiming to be experts in the field, are doing serious listening tests for the subtle qualities they would expect from a system before spending loads of money for it and taking it home?

That is like saying that the competitors doing test runs for the Indy 500 would be using old Chevys and Fords with stock tires because the expected performance levels at test runs are at "lower levels" than those at the real race.

How would listening to speakers in order to compare speaker-cable performance in a well-engineered test situation, be like testing a communications receiver with a poor antenna in a noisy industrial park?  Wouldn't it be more comparable to listening for the weakest signals under the most difficult band conditions through the best receiving antenna at the lowest possible noise location?

If a double-blind listening test with a room full of experts (many of these self-proclaimed of course), didn't call for a high enough performance level to distinguish the subtle qualities that you speak of, then give us an example of what kind of evaluation would.

Chances are, the acoustics in that room where the tests were conducted, the performance quality of the speakers used for the tests, and quality of the audio sources driving the speakers, equalled or exceeded anything the audiophools and audiophiles might have had in their homes.

Simple Don, there are several factors here. What do we know about this "test"?
Who are these "experts"?
What is their "credential" for claim of expertise"
Do they have an agenda/prejudice?
Were the test conditions published and scientifically controlled?
Are the conclusions drawn/published warranted?

It is fairly trivial to create a test for this sort of thing that looks reasonable on the surface but actually contains a number of what are called "confounding factors."

Good example in point is a "test CD" sent to me some years back by an advocate of "ABX" that contained test material that absolutely was incapable of revealing the sorts of differences that allegedly was being tested for - ergo a perfect result was had. The problem with the result was that there was no basis for making a differentiation, so none was had - flawed test, confounding factor.


Ummm... not sure what you mean here Don?
The aim at Indy is to achieve the highest performance, not a moderate or median level of performance.
If you want to test the limits, you need gear (cars, planes, rockets, audio, whatever) that is capable of reaching those limits - that's all I am saying.


Perhaps - depends on what you are testing?
I was attempting to give an example of a confounding factor that would render comparisons essentially meaningless. Obviously one that is exagerrated in degree in order to make clear the issue.


Double blind or not is another issue.
It does call for "high enough performance level"!
The question then is how does one objectively verify that level?
If you can tell me how these "tests" that make claims of "no difference" have verified the performance level of their equipment, I'll take their tests more seriously, ok?  ;D

FYI, afaik, they just don't verify anything much in objective terms - which is one of my biggest complaints about the alleged "science" of these tests. In my book it is necessary to at minimum provide enough objective information about the test conditions so that another "researcher" could duplicate the test. Have yet to see one published anywhere that would make that even vaguely possible.



Dunno what it exceeded or did not exceed.
That's the point.
I know audio enthusiasts who have systems that exceed the typical "high-end system" (pick where you want to find that or hear it) and those that do not. Chances are chances, and that doesn't make for an objectively valid test.

The BEST that anyone could say about the coat hanger test, or ANY of the other tests of this sort is that for THAT PARTICULAR TEST "X" was concluded. Nothing more.

             _-_-bear

Say what Thom??
People out there spend in inordinate amount of Buck$ to "buy the best" in audio, akin to those whose hobby it is to sponsor a IROC or INDY race car, or some sailboat, etc...

The quest for the best has nothing to do with the median of the home audio market.


Indeed. How one makes a determination is the key issue.
One might just start by measuring those things that are measurable and known?
Oddly, we never see that with these tests, now do we?
Well, a rhetorical question...

Nor did I say that it is.
There is BS in audio.
On both sides of this "audibility" issue.



Abusive Tom?
Not.
It's the same thing as calling them "gawd damn Slopbucketeers"...
Are ALL people who use SSB running "slopbucket" Tom?
Is that the impression you want to give?
Well it is IF you say such things.
The term "audiphool" is a negative term that paints a wide brush.
It implies that anyone who doesn't believe - in this case- that coat hanger wire sounds the same as audio cable XYZ is then an audiophool worthy of derision??
 
(... seems like I recall you had a website with that name, or one like it?? Soooo... maybe you have a dog in this fight??)

The coat hanger test was BS, and those who pick up on it and bandy it about as some sort of definitive proof of a particular prejudice are in error. Personally, I don't think it is a useful thing to permit this sort of mis-understanding to remain unquestioned nor for it to stand.

I challenge it and other statements like it in the forums that I participate in... not just here.


Thom, you can express doubts without using negative terms, eh?
And, I'm not taking anything personally at all, not sure why you get that idea.
Just taking a position as vigorously as those who are asserting one that I think is quite preposterous (and factually incorrect as well).

You yourself have said many times that these things are in the ear of the beholder. Your implication is that anyone who doesn't perceive a difference between the two is clearly anti-audiophile. I don't see how your implication is any better than the one your perceive being made by others.


That's awfully funny coming from a guy who builds expensive audio amplifiers for a living!!

Pot, kettle, black.

Nice talking to you.

--Thom
Killer Appetizer One Zesty Green Cannabis

Thom,

try some decafe?

you're confused...

           _-_-bear

avoiding the noise as I don't want to be part of the dispute, can someone explain to me why I need rear speakers like in these nice studio setups?

I have two ears. I have two large speakers at the front of the room and their 15" woofers are hooked up as the subwoofers. It sounds the same to me as the same stereo material played on a friends system that had 2 front, 2 rear, and a subwoofer.

I play a laserdisc video of star wars. The explosions and lasers sound the same. In the opening scene, I do not percieve the sound of the imperial cruiser passing overhead from the rear to the front as it pursues the millenium falcon. (putting aside of course that these things make no noise in space - so no wise acre remarks!)

So, why are two rear speakers used? Do I need special program material to notice? Does it make a difference really?

In the movie theater, I am not sure I can tell the speakers in behind from those in front. I can detect the ones on the sides if I am sitting in the right place.

(to digress , It may or may not be a moot topic as to whether I need amps that match the phase closely over the audio range - because a speaker might not, especially when used with a crossover. So if the woofer and tweeter are positioned in the same plane, but the woofer's signal lags because of inductance and the teeter leads because of capacitance, what effect does that have?)

Sorry for digressing and jumping topic, but aside from using the best electronic parts to make up the system, what should I do about rear speakers in general and is it worth the fuss?

The  home theater "standard" of 5.1 refers to a left and right front speaker, plus a center speaker, a subwoofer channel (the 'point one'), and two rear channel speakers. Unless you run the DVD player in 5.1 mode, you won't get the multiple channels of decoded information, you'll only get stereo. Most simple DVD players do not have 5 channels of output on the rear, so you'd need a "5.1 decoder" to get that information.

Some movies may have completely different sonic information on the rear channels in 5.1 while some may merely use them for "ambience" that depends on the movie and who decided what in the mix.

Does that explain it?

          _-_-bear

Corrections:
1) I'm not a smart fellow, but I don't hesitate to learn and experiment.
2) Painting and repainting are different things, though irrelevant to the topic.
3) I mean physical alignment result of that can't be corrected by any electrical means.
4) Are you a reader or a writer? I never said that time alignment does not matter.

Now, why do you think people don't take your opinions seriously, though ur smart fella?  :P

Initially there was a belief that the original recorded reverberation reproduced by rear speakers will overlap reflections from walls of listening room, but unfortunately the effect was like the result of using a cedar tree deodorant smells like a poop under a cedar tree.
But the industry went ahead before people realized that smell so movie makers quickly adopted new technology for environmental effects.

Later, in order to clear the marked for new production more and more channels were introduced. Like yesterday dealers pushed on my wife to sell a new Rainbow vacuum cleaner because a label is of a wrong color (i.e. obsolete model), while continued talking that their vacuum cleaners last more than 50 years and don't loose value.  ::)

It seems to me that since you are not a native English speaker (I am making an assumption here...) that some of your intended meaning is not quite clear, and that I may have misunderstood what you meant.

For example I'm not sure what you mean by "3)" above.



which people?
And, who said I am smart?? let me get my hands on him!! :P :P

Thom? I count Thom as a friend, and don't take his stomping about particularly seriously...

Btw, I have one of those Stewart-Warner inductively tuned table radios - I may be incorrect, but I think they were all made in natural brown bakelite. Fwiw, that is one tremendously good AM radio... I've had it since my Dad brought it home some time in the 50s... not sure, but he may have picked it out of the trash and repaired it, which I know he did to get TVs back then...  :D


         _-_-Wiggly Brontosaurus Two Great Crocidile Regressions

I mean that sound traveling from different drivers come to your bEar shifted by phase since distances are different.


Mine was painted, and the paint was scuffed in many places. Also, I've found on ePay and on other sites similar tuners, all of them were painted.

Is my English understandable now?

Ah, I see.

Well that would depend much on the type of speaker one is considering?

Single source fullrange speakers would not have that particular issue, including ESLs, some planars, etc... And for speakers that are wide-range, covering most of the audio spectrum (like some horns) that would be a secondary issue since the phase difference would likely be out of the regions where the ear is especially sensitive to this.

Multiple full range drivers in an array have other issues, such as comb filter effects WRT freq vs driver dimension...

D'Appolito wrote some papers in which he utilized the phase differences to control the polar response. Those are interesting.

Also, some in the field seem to feel that most phase differences are inaudible, especially the phase shifts that occur gradually across the entire audio spectrum (typical of most speakers...)

Others might prefer to look at the wavefront as being combined beyond a certain distance, and then only the frequency response varying with respect to angle?

I dunno, I try to avoid the problem by using fullrange or wide-range speakers myself.

In multiple driver systems, my experience is that the closer the drivers are to having a combined impulse response that is "aligned in time", either on axis, or on the axis to the preferred listening position, the better the system sounds in terms of spatial presentation. That's been my experience.



Hmmm... wonder who is painting them?
Do they look like factory painted pieces?
Maybe it is a West Coast thing? I'm on the East Coast, btw...
Should be pretty easy to determine this via a close inspection of the paint, paint type and technique, I would imagine.
I've seen a whole lot of bakelite table radios, and can not recall seeing a unit painted at the factory myself. Later on the manufacturers went away from Bakelite, and went with thermoplastic that had pigment, usually in white or brown, an occasional black as I recall. But these were smaller radios, made in the 60s and used subminiature tubes, not octals and loctals, as I recall.
I suspect there are others on here who know far more about the 50s vintage table radio than I do. I'm just recalling it from my childhood and from what I've seen at various places since then...


Would you prefer that I not say if I don't understand something?
Anyhow, think we've got it all cleared up now!  ;D

Regards,

          _-_-bear

No. Speed of sound does not depend on type of speakers.

You may draw lines between centers of 2 speakers to listener's ear. If their length is different no doubt a comb filter effect will start from some frequency. The bigger is the difference, the lower frequency it will start from. that's why I use 0.5" tweeters and 4" midrangers, and place them as close to each other as possible, and strictly vertically.
But if one speaker is on the level of your ear, another one is 40" higher, no doubt you'll hear deep bumps and dips, and their frequencies will depend on whether you sit, or stand.

Phase shift does not depend on the speed of sound in air.



I think that your example is not quite correct.

If the two drivers do not reproduce the same frequencies then there is no "comb filter" effect. (yes, most speakers overlap the drivers...) One is most likely to see a comb filter effect with multiple identical drivers in an array. The Gradient speaker is one method intended to eliminate the comb filter effect in a vertical array of identical drivers, iirc.

With closely spaced drivers like the tweeter and mid you discuss, there are phase and acoustic distance issues between the drivers that will effect their frequency response and polar response both.

I suggested that by using a single driver, like a fullrange ESL of sufficient height and thin enough width that one eliminates the sort of issues that are being discussed here - just one example.

But this is the forum for AMfone, so perhaps this discussion belongs on diyaudio, or another similar site?  ::)

                          _-_-bear

No comments...  8)

Yes. I do not use a 5.1 player, so there is no need for extra speakers till (or if) I get one. Stereo will do the same with the stuff I am using until then.

as the thread starter, I'm requesting it be locked and allowed to fade away. Everyone's had their say, and no minds have been changed.

Please lock it up and allow it to die a dignified death.

I was wondering if anyone has had the experience of being on the air, particularly on one of the higher bands, 20, 15, 10 and tuning up or calling CQ on a frequency only to find out that there was a QSO on that frequency that you couldn't hear because of either your antenna gain (you're on a dipole, they're on beams) and/or they're all on tall towers also and you're not?

I've noticed that the guys with big beams on tall towers consistently hear more DX on those bands, and work more DX on those bands compared with me or anyone else with a lower gain ant and lower ant than they have...

The correlation is in concept only, but seems to me the sort of thing that is going on here with folks who with good reason are incredulous about the ability to discern differences in things like "exotic" capacitors. The point being that if you didn't hear the other guy working the DX and only had your own rig to make a determination with as to what was or was not on the band you'd naturally think the band was dead. Same thing with the caps in concept. That's all there is to it. It's as simple as that.

If you need a technical basis for this happening, the link I posted earlier provides that.

As far as changing any minds, not sure that's possible if your mind is made up in advance though... and that's not actually my aim. The idea was to illuminate the issue and point out that while there may be some things in audio that are "BS" or "snake oil" there are far more that are not and have a solid basis. This is one of the latter.

Where I differ is when the tone and nature of the discussion becomes derisive across the board toward all things audio that are "exotic" or "high-end".

For almost all applications in ham radio and most home audio it makes absolutely no difference which cap type you use, as long as it is generally appropriate for the circuit.

                     _-_-Wrabbit Bear 2 Gorilla Cheetah Rabbit

Not that my opinion would matter that much but I second Derb's motion....All in favor?

DADDY!! Timmy took our ammunition away again and he won't give it back!!!

That is funny. In closing (maybe), here's a picture of one of my speakers. They are 4x2x2 FT. Note that there are no silk capacitors in them. All the drivers except the woofers are from a set of old Pioneer HPM-150's. The cylindrical space-age-looking tweeter is around here somewhere, I didn't use them. The speakers are sitting on 1 FT tall aluminum chassis video monitors. These make good stands.

The only problem is that the 14 cu. FT of the box devoted to the woofer is too much volume for them and they get unloaded at low frequencies (too much excursion). This is very annoying when trying to use the R-390A to extract the deep bass sound of the embedded secret and very narrow PSK signal out of the Russian AM shortwave radio station's carrier. If someone can suggest somethig there, it would be welcome. There is enough room for an 18" woofer.

The coil hanging down is part of an antenna  coupling coil I used in here for a while with a shortwave radio. It is made of CAT-5 cable. I ran a wire loop around the living room ceiling, and put it through a pair connected as a single wire, and then used another pair similarly between the radio's antenna input and ground. It got rid of alot of noise.

The rack on top of the speaker with the 4-#10 wire is for the 120VAC from the 20A air conditioner wall plug to the stereo and everything else in the corner. The power boxes came from a VAX and a PDP-11.

The two top units in the rack are the Ling 850 watt shaker table amps for bass, and in the bottom where can't be seen because of the door and fan cooling arrangement, are two Altec 175W tube amps. They drive the crud out of the midranges and tweeters. Every time I fire them up, maybe once a month, the crud just falls right off.

Opcomm,

Consider a high pass filter at 6dB or 12db/oct to eliminate the over excursion... you'd set the -3dB point at just below the resonant frequency of the port

Otoh, optimizing the cabinet volume vs. T/S parameters might alleviate the over excursion problem.  One can derive the T/S params with a few relatively simple bench tests.

It's not the diameter of the driver that matters, it's the Xmax (maximum linear excursion) of the driver and the T/S params for the driver + cabinet which will determine the limit of the power WRT frequency for the combination... there are freeware simulators that will pop this out instantly in graphical form as you change the box volume and/or T/S params and power input.

                _-_-bear

Just put a memory foam mattress inside, that's it.

I should say there's no port. The hole is for the mid and tweeter controls. That part of the enclosure is the space for the open-back mids. I'll look at the other stuff, thanks.

If it is a sealed box it will try to roll off at some frequency determined by the VAS (equivalent volume of the driver's displacement), fs (free air resonant freq) and the box volume, Vb, at 12dB/oct below that freq. But because this box is likely very large WRT the driver's VAS, it won't control the cone at a high enough frequency.

Bottom line is that the driver must be matched to the cabinet volume for a sealed box to operate properly, and that can only be determined using T/S parameters - the best way is to use one of those simulation programs (of which there are many now).

Or just use a highpass filter to limit the electrical energy going to the driver, and so decrease the excursion at freqs low enough to be a problem (like anything below ~20Hz. is a good idea here). A nice butterworth HP 4th order IC filter would work fine in series with the line going to the amp.


            _-_-bear

Again, the same like you add a resistor to your tuned circuit to lower it's Q add sound absorbing material inside of your box. The memory foam is the best I've found (it absorbs wide band of freqs). Also, if walls of your cabinet resonate (no doubt they are) glue a linoleum inside of them. HPF below Fs is *: speakers already roll off 12 dB/oct below Fs.

Wavebourn, stuffing the box with absorbant foam will do one of two things depending on the actual acoustic effect of said foam vs. frequency. Usually foam of any sort unless it is extremely thick has nil effect at LF, or put another way, as the frequency goes higher it usually absorbs more sound.

IF it is a good absorber at LF, then it will make the box appear larger which is likely the opposite of what is needed in this instance (probably). If it is a bad absorber at LF then it serves to reduce the box volume at LF which may be what is needed here, but that's probably not the best way to accomplish it - although unintended as it may be an ideal combination of bad LF absorption and good HF absorption could be an interesting way to "adjust" box volume and reduce rear radiation at the same time, but hard to control or measure in simulation (as in, how much, how thick, what density, etc...).

In terms of absorbing the rear midbass and up radiation from a driver, reducing reflections that re-radiate (in essence as "distortion"), if that's what we're talking about absorbing that energy is a good idea.

These speakers roll off in terms of frequency response or SPL[/u] below F3 not Fs at 12dB/oct, but NOT in terms of EXCURSION. The excursion actually continues to increase even though there is no increase in acoustic output.

Watch ur language please.

              _-_-bear

Mmmmm... I think what I wrote is not.



F3 is not because "people assume that roll-off less than 3 dB is inaudible."
It is because it a verifiable measurement of rolloff IN THE BOX.

Fs on the other hand is FREE AIR RESONANCE. No Box.


Read what Bob Cordell wrote about that.
I do not necessarily agree with Bob Cordell, but he's an authority on a number of audio related subjects. That being the "EBS" alignment. NOT what I am talking about.

Fs != F3 in 99.99% of all possible configurations.
Oh, going below Fs by -3dB also != F3.


Friend, I have no idea what you are trying to say here.

You can make a cabinet be damped WRT resonances and transmission of audio energy.
You can try to make the internal volume of a cabinet be absorptive.

So far there is no material that I know of that is a) very effective at LF vs. physical thickness and/or b) absorptive equally at HF vs. LF (the problem being that most materials are not particularly absorptive at LF.

The fact that "memory foam" appears to not spring back quickly does not automatically mean that it is either effective at not transmitting LF energy or absorbing LF energy (the other side of the same coin) - meaning that it is good at turning sonic vibrations into heat.

Long hair natural wool is regarded as one of the best in this regard, and it is not very good - at BEST it adds an effective 10% to the volume, which is the flip side of lowering the Fb of the system, eh?

Put this even more directly, if "memory foam" was as good as you seem to think, then it would be possible (based on its fantastic LF absorbtion) to build speaker systems that are much much smaller than what are required today and have the same LF response as a much larger cabinet built as is commonly done. Thus, all the myriad of companies, with engineers and Phds would all be made fools at once, if this were so. Now, such a thing could happen - but I doubt that this is going to be such a case.


Indeed, it has specific mechanical properties due to the way it is made.
However, it is still the same compound as "regular" foam, the difference is in the way the "foam" part is handled during manufacture. If it absorbs LF audio differently that has yet to be established (afaik) in any literature. It would be pretty easy to do some simple "lab" tests to establish the difference.


I guess the use of such language is up to the moderators - but I don't like it when you use it to characterize my posts.


Dude, he wrote that he was getting over excursion at extreme LF.
Did you read that?
Apparently not.

10-4 gud buddy.

          _-_-

.

Just a suggestion, here...

Since you guys are talking very directly to one another about a topic that doesn't seem to be drawing in any other protagonists, and you're not discussion capacitors per se, perhaps you two lovebirds should carry this on via email?

Just my $0.02.

--Thom
Kraft Advertisement One Zesty Grated Cheese

This thread is the King of the Dead Horses. All hail our corpse-horse masters!

odd that you'd say that Dave, since it is apparently the 5th most read thread in the Technical Forum?

         _-_-Wily Bear 2 Golden Chicken Roosts

Suspect most are 'rubbernecking' the 'train wreck' in progress... ;)

Steam or Diesel?

Passenger or Freight?

Domestic, Euro, India??  ::)

             ;D           _-_-bear

Here you go:

(http://wavebourn.com/images/audio/shelfjet_rubber_f.gif)

This studio monitors are built of a solid concrete (I don't have such composites as Harman has) with linoleum and memory foam inside.
Unfortunately, in order "have the same LF response as a much larger cabinet built as is commonly done." bigger area of cones is needed, or other means to match acoustic impedances like horns, while damping materials help to control resonances only, unlike in your virtual reality made of phrases taken without understanding of their meanings from popular literature.


Did you try to read an Elementary Physics schoolbook instead?  ;)

I am not going to comment what you wrote: anyway you'll complain to Moderator asking to remove my comments.

Good luck!  ;D

Wavy,

This is the AMfone forum.

I suggest that since you are a participant on DiyAudio.com, as I am, that you put your designs and physics up on that forum, and see if it flies or not. Forget about what I think or can't think of, ok?

Let's talk about radio, ham radio, and AM here.

People other than myself started this thread about caps, and their audibility, etc...
I have only tried to bring some information to light.

There is no need for me to comment on your good looking boxes... if you want my comments, then PM me with a link to your post on this topic or any topic like it on DIYaudio, alright then?

Good.

I'll try to avoid any further comments on topics that are OT in this thread.

       :D

                     WBear2GCR

Bear;
it does not matter: AM it, FM, RF, Audiofile, what else, but absorbing energy from speakers you can't increase loudness. Never. It is the law of physics.
"Oh you researchers of perpetual motion, how many harebrained ideas have you created in this search. You may as well join the gold-makers." (C) Leonardo da Vinci
More information: http://www.hp-gramatke.net/perpetuum/english/page0060.htm

Welp, I guess it's Safe to say then: That:...ah, better cabinetry design criteria are perpetually better with the square of the released volume of pressure..sound quality is correspondingly increased with the stability of the vibrating membrane..absorption factor isn't desired only for spills, leaks and wipes.  ;D

Now as to the crappacitor issue...? 8)

Translation: below main resonant frequency speakers drop 12 dB/Oct, like 2'nd order filters. On resonant frequency they excibit a peak (boom, really) that is the louder the higher is Q of resonating system. When you put a speaker into an enclosure stiffness of an air causes increase of a frequency of that main resonance, so the smaller is the box, the higher is the main resonance frequency is shifted up (i.e. from the higher frequency the speaker will start to roll off). So, in order to cover lower frequencies we need speakers with lower resonant frequencies in bigger boxes. The lower is the self resonant frequency of the speaker, the smaller the box we can afford.
Now, in order to divide flies and meatballs, let's talk about the main resonance: to avoid a "boomy" sound we need to lower Q of the resonating system. Whe know how to make Q less: to add something that will turn an energy of resonating system to heat: resistor in radio, or damping material in speaker boxes. If to "underdamp" sound will be boomy; if to "overdamp" bass will be rolled of.

No black magic at all!


It was discussed already: electric field repel and attract plates of capacitors even in an air. Change in distances change capacitances (remember Teremin, capacitive alarm detector?). Acoustical resonances happen in capacitors.
Properties of dielectrics also depend on strength of electric field. It means, capacitors are not linear, and non-linearity is frequency depended and phase shifted. Their capacitances and  losses depend on applied voltages and frequencies. If they are not linear, they distort signals, it is the axiom.
The question is, which capacitors, in which conditions, give less distortions. The answer can't be simple...

Rod Eliott has some useful information on his site: http://sound.westhost.com/articles/capacitors.htm

Don't recall saying anything about absorbing energy from speakers increasing loudness...  ::) ::) ??

Please do not either put words in my mouth, or misquote.
If I said that, please cite it as a quote.

But WRT perpetual motion, might not the laws of physics only apply locally?
Do they work properly in a black hole?
Do they work properly at or beyond the event horizon?
And, might not the universe as a whole turn out to be a perpetual motion machine?

Never mind...

       _-_-

What happened, somebody go get married while i was gone...;D....Wavy where's your sense of Humor Babe...My main interests have always been in construction practice in UHF to microwave regions..Cavity, Plane and Length Resonance are the issues in that realm... :D Filters are a plumbers delight... 8)

Calculate your opening aperture of the cavity for the desired bass response required Brother...an Let that air out OM... :D

Of course that's Old School thinken... I R an Old Guy Now... ;D


ya know, there's just to much drama in this world.....an Not Enough Humor...

Ah, yes! A device for sealing an aperture in the wall of a cavity including a tubular elastic membrane which extends from inside the cavity through the aperture to the exterior. A deformable cap closes the inner end of the tubular membrane. The membrane is radially tensioned, e.g., by an annular ring formed in the outer end of the tube to seal the membrane against the edges of the aperture.

Right?  ;D
(United States Patent 4809871)

can this thread b shot now?  ::)

---BANG---



LOL....

Herecy, huh?  ;D

I agree with Derb...  Time to CLOSE IT DOWN!

Burn on a stake!  ;D