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Sub-Woofer Question - AudioPhool Experts (which I am not - an expert, that is).




 
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Author Topic: Sub-Woofer Question - AudioPhool Experts (which I am not - an expert, that is).  (Read 23559 times)
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flintstone mop
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« Reply #25 on: December 14, 2009, 01:47:25 PM »


Depending on your home construction and WAF the ultimate solution is an Infinite Baffle configuration. That would use the floor, wall or ceiling as the baffle and the open space ("infinite") behind it. The advantage to that is that then the driver goes down all the way to Fs (free air resonance) rather than something higher when enclosed in a box, even a refrigerator sized one.

                               _-_-bear


Hi Bear,

Thanks for the info on the subs.  I'll check this stuff !!  As far as an Infinite baffle - I just can't do it - I can't cut a hole in the beautiful (and very expensive) hardwood floors that are in every room of the house  Tongue   I don't know why.  It doesn't make sense.  But so far, I just can't do it.  Maybe if Frank (GFZ) does it first in his new beach place  Cool
CHECK THIS LINK::::::

http://www.othermag.org/brownnoise.php
Steve , do you listen to a lot of pipe organ music where the low end will get down down down??? I think it's FACT that notes under 30hz will loosen those types of muscles.

I have to quit typing....my post might get censored.

Fred
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Fred KC4MOP
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« Reply #26 on: December 14, 2009, 02:31:56 PM »


I like my Velodyne.  Had it for years.  Well built, no problems, sounds great, looks purty...   Wink

Karl
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steve_qix
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« Reply #27 on: December 14, 2009, 11:11:52 PM »

I'm looking at all of the specs.  This is one of the subs I have been considering.

It's made by SVS.  There are 3 configuration modes (user configurable) 20hz, 15hz and 10hz (and sealed).  In 10hz mode, the unit is pretty good down to 10hz, but you sacrifice about 3dB of SPL as opposed to 20hz mode.

   

It's 20w x 27d x 22h and weighs 155 pounds (OUCH!).

This is the PB-13 Ultra.

Also checking others, but this one is definitely on the list.  Front firing, too! Any comments are certainly welcome and appreciated!
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WBear2GCR
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« Reply #28 on: December 16, 2009, 03:06:25 PM »



The port can only "play" at one frequency...

I'd try to listen to this thing before spending the $$ myself... might be great, dunno.

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ke7trp
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« Reply #29 on: December 16, 2009, 03:32:34 PM »

 It depends on what main speakers you have.   For example, I use Paradigm phantoms for the mains so I need a front firing sub for smooth sound. The phantoms produce very little low end.

Its nice to be able to tune the unit with the ports.  I spent most of my life building boxes with and without ports. A sealed box is always better if you have the amplifier power.  The ports only add at or around the one Freq and that area is boosted.  This discolors the music.  If done well its ok.

When bying your sub,  Decond on a few key factors:

Self powered?
Home theater?
Classic music?
Rock or modern?

Home theater means buying a large powerfull sub thats going to shake the room and wow movie viewers.   Classical means a ported box and Rock or modern means a ported unit with lots of 30 to 40HZ.

One of the coolest in my opinion is the old Carver subs.  Super small.  Really small. Lots of low end and lots of power.  My cousin has one and just loves it for his theater.  Very pleased with the performance.

Ebay item  150397282637






Clark


* carver.jpg (10.22 KB, 300x225 - viewed 431 times.)
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K6JEK
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« Reply #30 on: December 16, 2009, 09:19:54 PM »

...
I'd try to listen to this thing before spending the $$ myself... might be great, dunno.
                  _-_-
The owner of a high end audio store told me the other day "If it's a good subwoofer, you don't hear it."  That was after I asked if the monster Velodynes were on in addition to the KEF Reference 207/2's.  I didn't notice anything coming out of them.

At least I think they were Velodynes (two of them).  They looked like this:

http://www.velodyne.com/products/product.aspx?ID=3&sid=486d918d

They would not fit the bill at Steve's place nor at mine.

The KEFs.

http://www.kef.com/CA/Loudspeakers/Reference/207

I was listening to this very high end stuff just for fun after I gave up on the more modest speakers in the store.  I really didn't like the affordable stuff they had.
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« Reply #31 on: December 17, 2009, 12:09:13 AM »

At least I think they were Velodynes (two of them).  They looked like this:

http://www.velodyne.com/products/product.aspx?ID=3&sid=486d918d


Those Velodynes are real nice ! 
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WBear2GCR
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« Reply #32 on: December 17, 2009, 09:51:04 AM »



They all look good and the write-ups are all glowing.

Listen, your ears will tell the story.

Notice they claim 2 x 3kw amps (dual VC woofer)?

So, where do you plug this thing in??
What gauge is the line cord?

Also, the improved performance that is now available to almost all of these sub manufacturers is due to greatly improved heat/thermal handling of new designs, which means increased power handling. This coupled with high Xmax designs makes for much higher performance than 20 yrs back...

Fwiw, I would agree that if you don't hear the subs that is best. I'll go one past that, if you don't "hear" the speakers, then you've gotten somewhere.
 Grin

                      _-_-bear


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W1RKW
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« Reply #33 on: December 17, 2009, 04:30:47 PM »

 a nice pair of B&W's would eliminate the need for a SW and produce a nice sound stage to boot.
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« Reply #34 on: December 17, 2009, 04:38:31 PM »

If you like B&W  Embarrassed
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WBear2GCR
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« Reply #35 on: December 18, 2009, 09:06:58 AM »



No way will any B&W get down where QIX wants to go... dinosaur foot thuds...

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VE3GZB
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« Reply #36 on: December 18, 2009, 10:48:09 PM »


Any ideas? Suggestions? Experiences with good subs?  I'm all ears (as Ross Perot would say!).

Regards,

Steve


Mount them under the floor?
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K6JEK
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« Reply #37 on: December 19, 2009, 08:06:06 PM »

Now you guys have me wanting a sub-woofer.

Is it true that it can be placed almost anywhere like in the back of the room where there is space instead of in the front where there isn't?

The front L/R,  Carver Amazing III's, have  good low frequency response so I'd do a low crossover, assuming I can figure out how to set that.

Anyone try one of the wireless gizmos for feeding the sub?  Getting the wire to where I want the sub isn't going to be any fun.

We mostly listen to classical music but every now and then a dinosaur enters the room.  How will I know it's a dinosaur not just an elephant if I don't have a sub?

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ke7trp
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« Reply #38 on: December 19, 2009, 08:21:02 PM »

The sub is going to perform best when loaded on a wall or better yet, A corner.  I move my subs all around the room until I am happy.  But "most" of the time, I like to have the sub up front in the Corner of the room. The Crossover is going to be set on your preference.  You will have to listen to the the same music over and over and adjust the cut off and sub level.  I dont like hearing a Sub.. I like it to Fill.

C
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WBear2GCR
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« Reply #39 on: December 20, 2009, 08:12:10 PM »


I'm going to disagree almost completely with the advice in the earlier post(s) on sub placement.

It is true that the LF output will be boosted whenever any speaker (sub or not) is placed at a room boundary - the floor, the wall + floor, or 2 walls + floor, that does not in an of itself provide any benefits beyond the LF boost effect.

Open space is "pi" space. Add a floor and you have pi/2 space, add wall and you have pi/4 and two walls gives pi/8. So reducing the area where energy can radiate produces a type of "boost" over open or anechoic response for frequencies where this has an effect - which is generally speaking more as you go lower in frequency (the room dimensions providing some limits and other effects).

When you move a sub close or to a boundary, or when it fires to the floor it is taking advantage or being effected by this phenomena. A sub that fires from a point at the corner of the walls and floor starts to look a lot like a conical horn, fwiw. Actually, it is.

The biggest problem is that in 99% of all cases, and  that being 100% of anything that is not purely digital in the xover, the xover in the sub causes a delay in time for the start of the energy sent to the sub. Even IF the sub's driver was front firing and in the same vertical plane as the main speakers, and you had stereo subs (one per channel - or one per speaker in the room) the output of the sub would still be delayed WRT the main speakers! This creates a phase offset that makes the SUB's energy appear to be "disembodied" somewhat from the rest of the soundfield (assuming you have a spatial soundfield).

In order to make the sub's energy appear in approximately the proper time WRT the main speakers it would have to be physically (or acoustically) in front of the main speakers... of course most set ups do not permit this.

So, while you can place a sub almost anywhere, and putting it to the rear of the room or in the corner will get you LF boost (which may be needed by some subwoofers), it does present some problems in terms of integration into a system that provides more than flat amplitude response and is intented to also present a reasonably good phase or time response...

Next time - the issue of one vs. two or more subs...

                           _-_-bear

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Pete, WA2CWA
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« Reply #40 on: December 20, 2009, 11:26:16 PM »

Maybe some enterprising person could design a sub-woofer chair or some type of sitting area that incorporates the sub-woofer as an integral part. Combines the "pleasures" of hearing and feeling.
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« Reply #41 on: December 21, 2009, 08:38:15 AM »

Bear,

Minor point, but  a whole sphere, "360 volume (360 rotated through 360 for 3D)" is mathematically 2*PI space, where Pi radians = 180 degrees.

Add the floor or split the sphere in two and you have one Pi space.
Your corner is now reduced to Pi/16 space,  Grin

Audiophiles may have modified the definition.  I suppose we could even use true volumetric definitions for a spherical volume.... 4/3 Pi*r^3

For all,
In a bass reflex, or ported closed space you not only have the fundamental freq. that's "tuned", but you have the overtones, diminishing each octave.  That's why double tuned ports or double resonance load line cavities such as in the Bose(tm) can have overlapping and algebraically superimposed blending that sounds well with what looks like a very simple set of holes and /or resonance columns.
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RICK  *W3RSW*
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« Reply #42 on: December 21, 2009, 09:11:06 AM »



Ya, mentally challenged lately... sphere is 2pi... geez... have pity on the mentally challenged - we look and sound normal, but we're not...  Huh Lips sealed
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W3RSW
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« Reply #43 on: December 21, 2009, 12:57:33 PM »

I h'ain't normal neither. 
Now I wonder if PI rotationally into 3D isn't a 4*PI space?
Oh well...
-probably just a confusion of terms in vector phase space?  ..urk,
 Grin
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RICK  *W3RSW*
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« Reply #44 on: December 21, 2009, 05:03:31 PM »

Maybe some enterprising person could design a sub-woofer chair or some type of sitting area that incorporates the sub-woofer as an integral part. Combines the "pleasures" of hearing and feeling.

Actually, they do exist in the home theater realm.
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Bob
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« Reply #45 on: December 22, 2009, 02:00:43 PM »

Sub chairs do exist for home theater.  Not real audio.  Made to wow the Crowd.

In high end stereo (not home theater) you want all speakers up front.  The goal here is to reproduce the recording faithfully.

When you go to a concert, Does the Drummer and bass guitarist sit behind you?  NO. 

I use an audio control real time analyzer.  Most do not.  They are not that serious.  I have owned hundreds of speakers over the years.  We buy and sell audio. 

Experimentation is the key.  Do what you like.  Use what you like and enjoy.  I have $10,000 speakers here. I decided a while back that for me.  A set of vintage (real and not dept store crap) B and Os where clearly the best sounding speaker I ever heard.  So I kept them.  They might be Junk to the next guy. Audio does not have to be expensive.  I have a set of OLD JBL L12s in the other room.  We tested them at a high end audio store as my friend that owned the place never heard a set.  About 20 minutes into the audition he came in and said "get those F'in things out of here!" and got mad.  Garage sale 30 year old JBLs Blew his room full of High end audio away.

If you embark on this hobby... Be warned..  you WILL encounter AUDIO SNOBS.  I have met alot of them over the years.  Go to an audiophile party for a real good laugh.  These guys will sit around drinking cognac, smoking cigars and open virgin vinyl to play for the first time on $20,000 turntables..  Nobody is allowed to speak until the entire record is done. Then you sit around talk about the nuances of the strings in the band.. LOL  Every once in a while the guy would get up and meade a piece of Clay and lay it gently on a table.. And exclaim "i just found that resonace and got it!"

The truth to this thread is that choosing a sub is easy.  This is the least important choice to be made. Almost any decent sub will be just fine.  Its low end and if setup right, You cant hear it directly.

I have 3 or 4 powered subs in the store room.  To prove it, I will send steve one.
Clark
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WBear2GCR
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« Reply #46 on: December 22, 2009, 03:11:00 PM »


Clark is probably right - but there are just as many snobs in this hobby as in the other, or at least there are enough of them in both?

Ya think that's bad? How about art snobs ??

I prefer to hang with the DIY audio crowd myself. Much more grounded as a group. Sort of like the folks in ham radio who are homebrewers and build their own a lot... Or the folks who restore and modify boatanchors.

Most of the folks in the audio snobbery melieu usually seem to have a whole lot more $$ than actual knowledge, so that leads to a certain sort of insecurity and that leads to a "pack with a pecking order" situation very often. It happens, you know...

The opposite happens too, people with way way too much EE knowledge and zip appreciation of other matters... a good balance is nice.  Grin

                 _-_-bear
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« Reply #47 on: December 22, 2009, 03:36:57 PM »

Sub chairs do exist for home theater.  Not real audio.  Made to wow the Crowd.

In high end stereo (not home theater) you want all speakers up front.  The goal here is to reproduce the recording faithfully.

"home theater.  Not real audio.  Made to wow the Crowd."

Yep, that's what I paid the money for. Wow me every time I sit in front of the screen. I listen to my tunes either on an Ipod or from a box as background entertainment as I do other things. I have no time or patience to just sit in front of a box and listen to virgin vinyl, crusty tape, or CD's. Probably why I built so many sound activated light boxes back in the 70's.
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« Reply #48 on: December 22, 2009, 06:29:39 PM »



Pete, "boom and sizzle"?

I want the steak, not just the sizzle myself.

If the sound that is in the room is simply "there" and it is effortless, without electronic artifact and sounding utterly natural as if it were merely appearing as if by magic, that's what I want.

It's non-trivial to get the speakers to disappear, and even more daunting to get it to the point where it is as I just described. Most of the time even those who are striving for this goal don't get all the way there... but when you do... Voila!

                        _-_-
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« Reply #49 on: December 24, 2009, 06:02:02 PM »



An example of a modern 15" subwoofer driver:

http://www.diyaudio.com/forums/swap-meet/157259-kove-armageddon-15-1050rms.html

while there take a look around - if you'd like to see some spectacularly excellent DIY projects, you'll find them on this site!! Everything from built on a wood board to drop dead sculpture enclosures!! All DIY.

Also discussions of all matters audio, solid state, tubes and speakers of all types. Very little noise on the channel.

                       _-_-bear
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