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capacitor phools




 
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w8khk
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« Reply #25 on: January 19, 2008, 08:52:51 PM »


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.

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....
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« Reply #26 on: January 21, 2008, 09:22:22 AM »

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!! Grin Grin

                                                                       the Slab Bacon   
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« Reply #27 on: January 21, 2008, 05:39:44 PM »

Baco-bits,

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

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k4kyv
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Don
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« Reply #28 on: January 21, 2008, 06:42:09 PM »

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





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Don, K4KYV                                       AMI#5
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« Reply #29 on: January 21, 2008, 08:02:51 PM »

      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.
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flintstone mop
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« Reply #30 on: January 21, 2008, 09:00:04 PM »

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
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Fred KC4MOP
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« Reply #31 on: January 21, 2008, 09:54:11 PM »

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.
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VE7 Kilohertz
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« Reply #32 on: January 22, 2008, 01:13:01 AM »

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
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Tom WA3KLR
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« Reply #33 on: January 22, 2008, 06:18:29 PM »

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.
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« Reply #34 on: January 22, 2008, 09:55:55 PM »

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.
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Ed KB1HVS
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« Reply #35 on: January 23, 2008, 07:19:03 AM »

]

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! Smiley
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VE1IDX
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« Reply #36 on: January 23, 2008, 10:47:04 AM »

I am glad someone mentioned the fact that if you cannot hear the difference there is in fact no difference to be heard.  Wink 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? Roll Eyes 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 ?  Grin 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.
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flintstone mop
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« Reply #37 on: January 23, 2008, 11:06:56 AM »

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?HuhHuh?? 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
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« Reply #38 on: January 23, 2008, 11:45:25 AM »

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?HuhHuh?? 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
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« Reply #39 on: January 23, 2008, 05:36:21 PM »

]

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.

  That's why ACID was created my friend! Smiley
[/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?

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« Reply #40 on: January 23, 2008, 05:47:05 PM »

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.

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."  Shocked

Quote
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(?)

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!

Quote
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.

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


Quote
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?HuhHuh?? 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!!

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!

Quote
Well, enough chatter from MOP radio. Gotta get that RA250 wired up.
G'day...........................Fred

                _-_-bear
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Ian VK3KRI
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« Reply #41 on: January 24, 2008, 06:22:53 AM »


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.

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
 
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« Reply #42 on: January 24, 2008, 07:31:52 AM »

Quote
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  ??

And that the ionosphere, receiver AGC and detector add more than 1% distortion to the signal.
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« Reply #43 on: January 24, 2008, 08:20:51 AM »

It is sometimes a blessing to be half deaf..........
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« Reply #44 on: January 25, 2008, 07:28:50 PM »


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.

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
 

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.

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Ian VK3KRI
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« Reply #45 on: January 26, 2008, 12:13:45 AM »


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 !
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« Reply #46 on: January 26, 2008, 10:27:29 AM »

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!

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k4kyv
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« Reply #47 on: January 26, 2008, 10:58:55 AM »

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.
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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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« Reply #48 on: January 26, 2008, 07:34:25 PM »

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.

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k4kyv
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« Reply #49 on: January 27, 2008, 01:51:10 PM »

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  Wink )

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.
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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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