Audiophile quality powered subwoofer

[Audio_ELF]

vortecjr wrote... "you dont due two for more base, but just to maintain the l/r discrete channels."

Sorry vortecjr but can I put school teacher hat on for a moment ... you often (maybe always) write "due" when I think you mean "do" and it makes your posts hard to read (at least for me) ... hope my correction doesn't cause you offense.

 

Eloise

 

[vortecjr]

Now I will be scared to right (hehehe) anything. I can't fix the post because you added a post under me though. I had to read it a few times to realize how bad it was. wow!

How about this?

You don't use two subs for more base, but you use then to maintain the l/r discrete channels.

 

[Audio_ELF]

vortecjr ... sorry if I was being a pedant ... I'm unsure if you realised you were doing it ... hope I didn't offend.

 

[vortecjr]

to try and get some more headphones!

 

[jerryt]

@vortecjr: I don't think you use two subs to maintain the l/r discrete channels. Bass frequencys have very long wavelengths and you can't determine from where the sound is coming from, it's just all-over. You can actually feed the sub a mono signal with both left and right channels since their separation is useless.

Using 2 or more subs is done to combat room resonances and standing waves, placement of the subs being the key factor here.

 

jerryt

 

[The Computer Audiophile]

"Bass frequencys have very long wavelengths and you can't determine from where the sound is coming from, it's just all-over."

 

Exactly. The wavelengths are greater than the space between your ears so you can't tell where they emanate from.

 

[vortecjr]

The point I was making is that the left and right channels have different information when recorded. So the left may not have the same sound as the right at any given point in time. The direction and all that is a seperate issue. Also, put this way you are mono with one sub combining the l/r channel information.

 

[machinehead]

Got a deal on an ATC C1 sub, it should be here on Monday. Looking forward to it.....

 

[Stretch]

Never heard an ATC sub but if it's anything like their speakers you'll be loving life.

 

Just thought I'd put in a plug for my favorite ID sub maker, Epik. I have two of their big 18" home theater subs and they're terrific. They also make a very compact, sealed sub for two channel systems that is on sale right now and I think pretty close to unbeatable at the price point.

 

http://www.epiksubwoofers.com/sealedvanquish.html

 

 

 

[Gulinias]

I am more than happy with my JL Audio 110/ The bass is fast, tight and articulate. It seems to blend exceptionally well with my Focals. I think it is hard to wrong with a Rel or JL sub but there are other fine subs.

 

[bdiament]

One thing I keep seeing repeated is the mistaken assumption that humans cannot localize bass frequencies. I believe this stems from folks confusing the fact that bass radiates omnidirectionally (in all directions), thinking that it will thus be non-directional (from all directions).

 

Setups where one cannot localize bass are setups where room resonances are being sufficiently excited to clog the sound and confuse the listener. This is exacerbated by the frequently seen "recommendation" of placing subwoofers in corners or "behind the couch" or any other place that is not in close proximity to a well placed main pair.

 

Besides, how can bass localization be "impossible" if I can find the a hidden subwoofer by ear? (In a recent audition, I noticed all the low bass in the super-expensive, computer controlled, room "compensated" surround system I was listening to was coming from behind me. I looked behind the pair of panels delivering the rear center sound and sure enough, there was the sub. Crossed over quite low too.)

 

This same misconception leads folks to using one subwoofer, as if real life is not "stereo" all the way down. It is. Wavefronts, even very low frequency wavefronts do not arrive at our ears simultaneously, unless they are centered directly in front of, behind, above or below us. Anything not directly centered will have a time arrival difference at our ears. (We localize sounds, not simply via amplitude differences but also via frequency and arrival time differences. If Nature could have gotten by with fewer than these three types of cues, I'm pretty confident it would have done so by now.)

 

Low bass, just like all the rest of the audible frequency spectrum, requires stereo (i.e. left sub and right sub) if it is going to be consistent with the main pair. It is much easier to make two subs audibly "disappear" as sound sources than it is to make one disappear. This is just one reason why many subwoofer installations are not satisfying to those who recognize what real bass sounds like. (By the way, "disappearing as sound sources" should not to be confused with our ability to localize bass, any more than the main pair disappearing as sound sources should be confused with our ability to localize frequencies they are delivering.)

 

In systems where I've heard subs successfully integrated (including, I'd like to think, my own studio), the main pair is left full range and the subs are crossed over quite low. I've heard good systems where the subs cross over at 40 Hz. In my own system, they cross over at 30 Hz. (The studio measures ± 1.5 dB all the way down.)

 

Very important with subs is the fact that they will present energy to excite the room's fundamental resonant modes. Most systems excite the first and second (perhaps third) harmonics of these modes. Good subs will excite the fundamentals. Proper room treatment is necessary to hear the low bass contained in recordings at its best.

 

I have yet to hear an electronic room treatment that does not exact a heavy sonic price - to my ears anyway. In my opinion, creating an "error" in the speakers in an attempt to "compensate" for an error in the room doesn't work. Room modes are time-based problems (with somemanifestations in the amplitude domain), that cannot be addressed with amplitude-based solutions. Seems to me like trying to fix a broken arm by wearing a different hat. ;-}

 

Just my perspective of course.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[The Computer Audiophile]

Here is some interesting info on sound localization.

 

From Wikipedia: Link

 

"Evaluation for low frequencies

 

For low frequencies below 800 Hz the dimensions of the head (ear distance 21.5 cm, corresponding to an interaural time delay of 625 µs), are smaller than the half wavelength of the sound waves. So the auditory system can determine phase delays between both ears very precisely. Interaural level difference are very low in this frequency range, so that a precise evaluation of the input direction is nearly impossible on the basis of level differences. Signals with frequencies below 80 Hz can no more be localized, because the phase differences between both ears become too small for a directional evaluation."

 

[bdiament]

Hi Chris,

 

The author neglects time arrival or the wavefront. Time arrival differences between our ears, for a non-centered sound are the same for 20 Hz as they are for 2000 Hz. The speed of sound is not changing with frequency.

 

Besides, take a good, low distortion sub and play a very low frequency tone through it, at a low enough volume to stay within the sub's low distortion spec. With your eyes closed, see if you can tell where the sub is. I think you'll find it as easy as locating a tweeter playing a high frequency tone.

 

I often say looking to Wikipedia for facts is like looking to Congress for Honor. ;-}

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[The Computer Audiophile]

Hi Barry - I agree locating a sub is not a tough thing to do. I'll take that ABX blind test any time :~)

 

[Gedlee]

Several comments:

 

Many things have been said here about me, many are incorrect and I'd like to clear them up. I didn't start out selling subs, I didn't want to, still don't actually. Because my subs aren't any better than anyone else's subs (well maybe some) - subs are subs, it's how they are setup that makes the difference. I started selling subs because people wanted them to match the mains that I do sell and do claim to be exceptional. But buy your subs anywhere that you want, it doesn't matter.

 

I do not have a patent on the sub that I sell, and I never applied for patents on drivers, nor for any sub patent that was not issued. I do have a patent on the use of an Acoustic Lever, but I do not sell subs using this technology.

 

I do say that multiple subs are the only way to achieve truely excpetional bass in a small room. My expertise is LFs in small rooms. In studying them I found that it was the statistical nature of the modes at LFs that was the problem. No two rooms are the same so you really have to look at the general problem statistically. It turns out that one sub yields a large spatial and frequency variation to the sound field in any room. Two subs cuts that in have (in general) and three to a third, etc. etc. There is no "magic" number, but beyond three the benefits are diminishing fast. There are no "magic" locations either, although some are marginally better than others.

 

So stated quite simply, use two subs and put them anywhere - except near the mains and each other. This will be a big improvement. Set them up with measurements will improve it still more. Add a third and yet another improvement. Put one up off the floor and one in a corner - another improvement. Add a forth, sometimes one tuned very low and others higher. All will be improvements and all will be room specific. There is no one sub type and one location or anything else that works in every case.

 

[Part-Time Audiophile]

Mr Geddes -- thanks for joining us over here on CA!

 

More subs = better sound? As an idea, I find this attractive. In practice, I'm left wondering how to do it.

 

Most subs can take either speaker-level in or line-level. Some can do both. Some can run slaved to another sub. I'm not sure, but I think you can daisy-chain more than one sub off of any other, but I suppose that that may vary by manufacturer.

 

So, if you're going to add more than one sub, how ought you to connect it in? Slave it to a master? Is there any benefit to going this route or not going this route?

 

Or, should you simply have the line-out-left go to the left sub and the line-out-right to the right sub? If the latter, adding a third becomes problematic.

 

Thanks!

 

[Gedlee]

The best is to use a DCX2496 driven from the mono sub out from a reciever, or just sum the left and right channels. With this unit you can drive each sub independently with its own EQ, gain, delay, phase, everything. Otherwise I just use the sub out into the line level for each sub. I always set the sub parameters from measurements. Using multiple subs can be elaborate or simple, either way more than one is better than one and more control is better than less. Mesaurements are almost a necessity, but these days thats pretty standard. With free software like HolmImpulse its trivial.

 

[audiofils]

Martin Logan makes a series of very nice subs, ranging rom $500 to $3,500. I have used with great pleasure a ML Grotto ($1500). REL is also a very good and safe choice, subwoofers is what they do!

 

[Gulinias]

I am going to back to the JL 110 Fathom. I have owned Martin Logan subs and they are very nice. I still think the JL is a better sub and easy to blend, Do not overlook them because they have car audio speakers. I would point out so does Focal and do all the Electra and Utopia owners worry about that? You need not worry about JL either. I have a nice system using those two companies who happen to also make car speakers.

 

[Gulinias]

The Vandersteen subs are nice and it has been years since I heard one. I do not remember them ever being cheap? They would be a fine choice as would Aerial and Revel. I do not care for the Paradigm subs at 2k or less but I understand the higher ones are nice. My son owns a SVS 13 ultra and I think for most two channel situations the 12 series be better. It is nice but harder to integrate into the room. I am sure in the right room and with patience they could be very good. I also have heard Rythmik and they are very nice. Submersive I have never heard but they and HSU have their fans for sure. The James got great write ups years ago though from the pictures the new line is stone cold fugly. These are just a few of the Brands beside JL,Rel and ML that you could listen to depending on the money you have and the availability of them. I guess is you have a Wilson dealer their latest powered sub is most likely very good. I am sure there are many more I have forgot about.

 

[earflappin]

Rythmik is another good sub choice. They use servo control technology, have been tested to be very close to the JL subs and cost much less due to their consumer direct model and low overhead.

 

[barrows]

+1 for JL Audio. I used a stereo pair of JL F-112s matched to Avalon Ascendant speakers for a show setup and the subs integrated with the (very fast and articulate) Avalons very well-crossed in at 40 Hz. If one is looking for accurate, deep bass, that will not muck up the tonal and/or dimensional qualities of the main speakers, JL Audio subs need to be auditioned.

Plan on a stereo pair of subs (at least eventually)- even though low frequency wavelengths cannot be located-the leading edge transient can be located-well set up subs will add dimensionality to a system.

RE: high level (from amp speaker terminals) input to JL subs-I always recommend taking the signal from the amp to the subs-the folks at JL can let one know how to make a simple circuit to allow one to connect the JL subs to the amplifier output-this is an easy thing to work out.

 

[Gedlee]

"even though low frequency wavelengths cannot be located-the leading edge transient can be located-well" - the leading edges are high frequencies and do not reach the sub so this is not correct. The leading edges are handled by the mains and that is where you localize the sound, the sub just reinforces the subjective sense of having a good "bottom" end. But the subs do not provide any sound localization ques (unless they are distorting, in which case these are HFs from the sub and you will locailize on those).

 

[bdiament]

Perhaps there is some confusion regarding the "leading edge" (as a higher frequency transient) and the low frequency wavefront itself.

 

A low frequency wavefront from the side does not arrive at both ears simultaneously and therein lies one type of cue (of the three types) we use to localize sounds.

 

Turn off the main pair and feed a good, low distortion sub the low frequency component of a music signal (not sine waves, which are not like music signals). Or take the sub outdoors. Do this at a low enough level so as not to push the sub into creating higher frequency harmonics (distortion). Close your eyes and the sub will be as easy to locate as a tweeter playing a high frequency sound.

 

We hear real life in stereo. All the way down.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[Gedlee]

The phase difference from the two ears below 100 Hz for any angle of incidence are negligable as are the level differences. There simply is nothing on which the ear can determine the direction.

 

I have not tried your test, but I would say this; 1) its not altogether that relavent because there is no masking from the higher frequencies nor are the HF cues present, hence it's an unreal situation. With the mains on the HF cues will dominate. 2) when multiple subs are used then they are not localizable if they are setup right and I suspect that even in the test that you propose they would not be localizable. In a room there simply is nothing that the ear can use to determine direction at LF.