Velodyne Digital Drive Series subwoofer in stereo

interesting reminder about MONO bass was recorded at the LP

R U the same Opalchip who's on the Fuji forums?

Thanks for the backup explanation, btw. :)

UPDATE - This may be some explanation for the discrepancy in opinions here. Last night I experimented a bit with a 40 hz test tone to see if I could hear where it was coming from. This wasn't scientific since I knew where it was, but I'm pretty sure at LOW and MODERATE volume I couldn't "hear" it's location.

HOWEVER - above a certain fairly loud volume point, I think I could FEEL where it came from, literally - through my clothes. This makes sense (I think) - the primary pressure impulses are hitting your body from a specific direction, and you pick it up more on that side than on the other, just like wind blowing at you.

And the volume is important - just as it's much harder to tell the direction that a light breeze is coming from than a stiff wind is hitting you from.

It's possible that your brain can integrate the directional information felt by your overall body with the non-directional ear input, so that you think you are "hearing" it from there - or in essence ARE hearing it.

I then played some LOUD rock/blues with electric bass, probably centered around 65 hz or so, which I remembered being way over to the left side. I sent it through my main speakers ONLY and concentrated on what was happening. (CD was Joe Louis Walker - Great Guitars)

I could "tell" (not necessarily "hear") that the bass was from the left, and I'd guess it was a combination of feeling the impulses bodily and the higher overtone cues. But the next step would be to try it with the single sub crossed over high enough to really exclude the mains from the lower frequencies and see if the bass "imaging" suffered. Unfortunately the sub now has a custom fixed crossover point mated to my speakers and I can't do that easily :(

In addition, I'm giving the sub away to my cousin this weekend and won't have one for awhile. WAF issues - my wife wants me to get one (or two) of the smaller long-throw cube types.

But my guess is that both sides of this argument have merit depending on SPL and source material:

--At high enough SPL the brain may incorporate information that DOES NOT COME FROM THE EARS, and insert it into the brain's locatization algorithm. I'm not sure if this is anything normally considered in acoustic theory.

--In addition, of course, the source material actually has to have stereo bass - which as we've discussed before is virtually non-existent on vinyl lp's. So for vinyl people like myself, two subs is a total waste. For CD it may be desirable depending on how loud you listen and how much source material has the true bass frequencies actually mixed to one side. And for DVD it probably should be a good idea.

Hey - it's just been slow at work, and I enjoy a good debate. You don't think I totally believe all this stuff do you? :) Despite everything I said - I DO keep my sub to the Right of center which is where all the low register instruments are - the cellos, double basses, tubas, etc. of the orchestra is - just in case it does make a difference.

Opalchip...LOL..I really enjoyed getting under your skin.
No doubt your very brilliant. It's been a pleasure.My only point is, I as well as others enjoy what stereo subs do for the music and movies.Thanks for all the great info.Will it stop me from ever using two subs again..not hardly. Just like a die hard tube fan, we all have our preferences whether anyone else likes it or not.
It may not be sane for some.But hey there's nothing really sane about the hobby anyway.Lighten up.. it's only audio.

Good listening!

re: Spacekadet's original post -

Well, since I don't know much about DVD/Home theatre I just called Velodyne tech support directly - and they completely agreed that there should be no "stereo" advantage in having 2 subs. He stated that, even for home theater, the only advantage of 2 subs is, depending on the room, having a smoother response curve attainable across a very wide or deep seating area. He specifically reiterated that the frequencies emanating from a DD-12 or DD-15 are completely non-directional for movies or music. I'd trust the manufacturer more than some Audiogon knowitalls (like me, for example).

He also said that the bass output from one DD-12 is about the same as two DD-10's, so it's (IMHO) an insane waste to buy 2 DD-10's at $2,000 each instead of one DD-12 at $2400, or one DD-15 at $3,000.

First of all - I'm not saying there's anything WRONG with having two subs. It may make placement (which is the REAL issue people should focus on with subwoofers) easier in some rooms. And yes, I did have two smaller 12" Velodynes before I sold them to go with a single larger one, which I keep in a slightly off center position - not in a corner.

The reason you have the potential for multiple subs for movies is because some DVD's may place bass tracks in multiple locations - intentionally WAY out of phase for FX purposes - not for music. You can hear that because two sub channels may be mixed 90 degrees apart. But we (at least I) haven't been talking about DVD/Home theater, which I have no interest in. Perhaps I should have been more specific.

As people have said above, the STEREO location of a piano, for your example, even at the 27.5hz Low A comes from the ample myriad of higher pitched overtones that ONLY arrive through the mains. Good subwoofers (if set up properly) playing NORMALLY recorded music, especially on LP - which is all I listen to - are fed no recognizable stereo information through the crossover to transmit. It isn't there unless intentionally placed by the engineer using digital delay effects - like done in a DVD.

In a true musical stereo recording, the pure bass frequencies cannot arrive at the mics far enough out of phase to be audibly placed - only the overtones can. Even in what is called an "exaggerated separation"/ "ping pong" effect by engineers, 2 stereo mics are placed maybe 10 feet apart with a 3rd one in the center. Even assuming the lows aren't later panned to the center during mixing (which they are), the TRUE bass might be out of phase enough to jump a needle from the groove, but still not enough for you to guess where it's coming from.

re: "Both subs responded at different times depending on who was playing. Apparently there are recordings with the lowest notes in stereo on some cds." Or, as you said earlier, "I can put my hands on each driver simultaneously and feel them vibrate at different times on the same tracks."
- - - - Of course you can! Nobody said the recorded signals to both channels are identical - but that doesn't at all mean if you had your eyes closed (and didn't already know the music) you could point to where the bass is coming from.

Anyway, I give up on this one... there's no argument that defeats the Magic Ear theory.

re: Bumblebee flight

From Straightdope.com:
"The basic principles of bumblebee flight, and insect flight generally, have been pretty well understood for many years. Somehow, though, the idea that bees "violate aerodynamic theory" got EMBEDDED IN FOLKLORE."

From David Wilkinson of Quarksoft:
"bringing two wings flat against each other and then moving them apart, very strong vortices were produced which could generate unexpectedly large lift. The earlier "disproof" was based on an inadequate model but THE STORY HAS AN INSTANT AND LASTING ATTRACTION TO THE NON-TECHNICAL MIND."

'Nuff Said.

Quick quiz ..have you ever tried it? Most of the nay sayers are the same people who have never tried stereo subs. Also you've forgotten the Piano goes deep into the 20 Hz range. Oh I forgot the Piano's not a musical instrument either... right? Or you'll give me your theory on why I or anyone else shouldn't be able to detect it's presence in stereo..right.

What if I had 3 bassist in the same recording from left to right. You trying to tell me the stereo subs can't differentiate between the right and left player? Even at the lowest frequency of 41 Hz. I've already tried this using indentical subs. Both subs responded at different times depending on who was playing. Apparently there are recordings with the lowest notes in stereo on some cds.

It's possible to have this in a movie track. Why do you not believe it's possible in some other recordings? I guess some people know more than the engineers of Lexicon and Meridian who have mutliple sub outputs just for such a thing.

Next thing you'll tell me is that bumble bees can't actually fly. Because there's not a shread of evindence that suggests otherwise. Me and 4 billion other folks just imagine seeing them fly ..right.

Au contraire, the tone of my last post was intended to put some reality into the guys who were bashing Truthseeker personally without offering one shred of backup other than their own unique "experience". And they still aren't, other than the "magical human ear" theory - which is far less plausible than the "magic human imagination" theory, formerly known as the placebo effect, or the out-of-phase sound effect.

The 65 Hz crossover point was custom chosen for me to match my speakers by Velodyne themselves at LOWER than the stock sub's point. And obviously it's not an infinite slope crossover so my mains are operating well below 65hz. The stock Velodyne DD-18, by the way, has a fixed, built in high-pass at 80hz. But I guess there's people here who know more than the Velodyne engineers.

Quick quiz - Do you know how low 65 hz. actually is? It's the very LOWEST note on a cello or a BASS trombone. Tenor trombone's lowest is 82 hz. The very lowest note written for a human bass voice is the same. Low E on a Guitar is also at about 82hz. Timpani - 87 hz. The very LOWEST note an acoustic double bass or bass tuba can possibly play is about 42 to 44hz. And nearly all the notes played even on double bass or tuba are above 63 hz and up to 300 hz. They're not down there banging the low E in every measure.

So what kind of bass are you all talking about? Exactly what instruments or pieces of music sound so much better in "stereo" bass? Organ and Tuba duets?

Opalchip you come across like the cock of the walk with the tone of your last post. Tell you what my friend..how about you turn off that subwoofer. Use only your fullrange speakers, take one and cut it's low frequency extention off at 65 Hz. Listen to some well recorded full scale music in stereo.
Come back and tell me you can't hear an improvement running both speakers full range in stereo. I'll tell you.. you need to find a new hobby!

I've read some of the scientific papers you touch on. But it still can't explain what the human ear perceives as a whole.If everything you say is the absolute. Maybe most of us only need one full range speaker and a matching monitor.. since we can't distinguish mono from stereo bass any way.

What kind of bass are you talking about? Acoustic Bass,synthesized crap or movie bass.

It's just a stone cold fact that 65hz bass (which is where I cross over my Velodyne with full range speakers) is not locatable because of the extreme -about 15 feet- wavelength. There is simply not enough phase difference from one side of your head to the other for your brain to differentiate. Anyone who thinks they can is hopelessly delusional. So there are ONLY 6 possibilities:

1. The guys who hear bass in stereo have sub/small satellite systems with their variable crossover frequencies set way too high.

2. The guys who hear bass in stereo are actually hearing the effect of room nodes from the unpredictable interaction of the two subs nearly identical output, and interpreting that as "better" bass.

3. The guys who THINK they can hear bass in stereo on CD's have suboptimal systems with audible distortion coming from their subs which allows them to "locate" the subs output.

4. The guys who are SURE they can hear bass in stereo on CD's have vivid imaginations, are gullible, and therefore probably own Wilson Watt/Puppies, too.

5. The guys who are SURE they can hear bass in stereo on LP's are hopeless romantics, because - I got bad news for you - it ain't there. Even Direct Disk recordings have to be mixed down properly through the board so you can play the damn thing back. Here's a quote from a basic LP mastering text,

"Why is it so important for mixes to be mostly in phase and the bass being in mono?

If the mix is in phase (mono), the cutter stylus will move from left to right - if the mix is out of phase (stereo) it causes the stylus to move up and down. Too much up and down movement (out-of-phase) will produce a groove that's too shallow or interrupted. This will cause the playback needle to jump, especially the bottom end is very critical. If the bass is in stereo, the cutter stylus will leave the surface of the record – the plate will be unusable."

6. And last - They guys who ACTUALLY CAN hear stereo bass have HUGE HEADS - so their ears are far enough apart that the long wavelengths present enough phase shift. Of course, these guys can't use traditional headphones, and the large head has very negative WAF.

My Rel Storm 3 has its crossover set at about 28 hertz, and it sits in a corner. I am generally not finding that the deep bass localized to that corner. Instead, it seems to emanate from between the mains, possibly sometimes just off the midline towards the sub-bass unit, but usually not.

On the other hand, I had a passive subwoofer in the back of my van, and it was clearly localizable to.....the back of the van. I don't know what frequency the crossover was set at on the amp feeding the subwoofer in the van, however.

Truthseeker and Cryptical -- Excellent information -- thanks!

After reading much of this debate, it is good to see that Raul & Truthseeker agree. Both agree when using low distortion subs at low frequencies (less than 40hz or so) that one cannot determine the location where those very low notes emanate from.

At these low frequencies the wavelenghs are so large, relative to the distance between the ears, that the source cannot be localized. This is because wavelength is inversely proportional to frequency (thus reducing the frequency by 50%, as from 40 hz to 20 hz, the wavelength is doubled in size).

Using a large driver with very low distortion (such as the Velodyne DD-15 or DD-18, rated at < 0.5% distortion), with a relatively low crossover point, so that the sub puts out very little information above 80 hz (relative to the mains), which is located in a time-coherent location (with correct phase, of course), when placed in a room (as opposed to placement outdoors suspended above the ground) the spatial cues for locating deep low frequencey notes are lacking, so the speaker's location cannot be detected.

If the crossover point is set so high as to allow upper bass (and higher) frequencies to be audible, then spatial cues become increasingly present and identifiable. Smaller drivers and higher crossover frequencies result in the intrusion of subwoofers into regions where they should not intrude.

However, if the equipment and room requires a setup where subwoofers operate at upper bass and higher, then they will be locatable by ear. Under these circumstances, although the location of the low bass notes cannot be localized, their higher level harmonics (and other spuriae) will be audible, thus allowing a degree of localization to be perceived. This is not ideal.

Ideally, the mains will create the soundstage - not the subwoofers. One or more very high quality subs with low crossover points, which are ideally matched to both the main speakers and the room, are the best way to go. I hope we can all agree on this last sentence.

By the way, I am not sure how much phase and time coherence affect this, but it seems logical to always strive for the correct phase and the most time coherent location feasible in a given room with any given system.

I really enjoyed reading the debate. Every opinion is welcome. Personal attacks are not.

What I would like to know is, assuming cost is no object, how many subs are best and how should they be placed in relation to each other?

Dear Truthseeker: +++++ " . If you play a 30, 40, 50hz pure tone thru a low distortion sub (<10%THD), YOU WILL NOT BE ABLE TO TELL WHERE IT IS COMING FROM " +++++

I agree with you on those frecuencies.

Regards and enjoy the music.
Raul.

Or maybe he just doesn't want to waste his time.

I was looking for a thoughtful rebuttal.Perhaps you are not up to the task today.

[email protected] and Truthspewer remind me of the Borgs from Star Trek. When they say " Your resistance is futile".

Just because we do not want to play in you guys sand box. You get upset. I'm here to tell you ..It's alright.. there's plenty of sand boxes for everyone!!LOL

I'm sure you'll find some more folks to come over and play in yours.Now go back over there and make sand castles.:-)
Oh yeah don't forget to take Truthspewer with ya! He said he was outta here days ago! I think one of the other kids threw sand in his eyes.Because he hasn't found his way out yet!

"read this thread and check back in a week or so."That is your answer?Are you serious?
If humans are unable to localize a pure 40 hz tone then no amount of subwoofers producing this tone are going to change this.This is a know FACT in most of the world but then again I do not live in YOUR world.
Now if you talked about signal re-enforcement/cancellations etc I could understand the avdantages of 2 subs.However you are claiming a stereo effect.That is a fairytale in the rest of the world.
I feel sorry for the moderators on this thread.

>>Next you'll be talking about animal hearing experiments<<

You would make the perfect species.

>>This fact makes a great difference in what you say.<<

Raul, can you articulate what the difference is?

The fact that the low pass slope starts out at 12db merely means that its initial rolloff is rather shallow...just like some of the respondents in this thread. If you read Velodyne's website, you'll find that the 12db/octave slope is its INITIAL slope, and that it drops off quite sharply after that...as high as 48db/octave!

Once again, this has nothing to do with one's ability to detect the location of deep bass. If you play a 30, 40, 50hz pure tone thru a low distortion sub (<10%THD), YOU WILL NOT BE ABLE TO TELL WHERE IT IS COMING FROM...PERIOD!!!!!!

If you say you CAN tell where that pure tone is coming from, not only are you completely delusional, but you probably believe in magic and all other sorts of nonsense. Try the above experiment and prove it to yourself....you obviously don't believe ME or ANYBODY ELSE who has bothered to do the research.

And if you can't tell where those low notes are coming from, YOU CAN'T PERCEIVE IT IN STEREO...PERIOD!!! What don't you understand about this?

So much has been written on this subject matter that it never ceases to amaze me how gullible people are who still force themselves to believe otherwise. Yeah, the earth is flat too...phhht.

If you want to mitigate the financial damage you've already done by wasting money on two subs, at least make the most out of the situation. Get an spl and chart paper and locate the subs so that they excite as many room modes as possilbe.
Better yet, place those left/right subs directly to the sides of your listening couch for an "ENHANCED perception of bass". This effect is only good from around 40-80hz, but is NOT "stereo bass". It's due to hrtf's...head related transfer functions. David Greisinger (Lexicon's "Bass Enhance") is one of the most respected bass researchers in the world and you would do well to read up on his research. Floyd Toole (Canada's National Research Council, head of Harman International Research Group) and Tom Nousaine are also close to his equals. Also pose these questions to psychoacousticians, acoustical engineers, and Phd.'s that you may come across.
Don't listen to me or the children in this thread. Read and listen for yourself. Perhaps some of you responders are subwoofer sellers and have a vested interest in perpetuating the false notion of stereo bass in order to sell more subs???

Regarding the Velodyne crossover slope, that's merely indicative of Velodyne's marketing choices, priorities, and compromises. Velodyne knows that most folks have a processor that gives a xover slope of 24db/octave, so why duplicate that in the sub? Why not give them something different? Same goes with their passive high pass filter. It's a shallow 6db/octave slope which some folks prefer, but most folks will choose the steeper 12db/octave high pass filter in their processor. A shallowe slope is ok, but if you cross it over rather high (80hz or >), the blend with the mains may sound a little bloated in the crossover region due to the overabundance of bass information there. Hey, it's all a matter of taste, but don't confuse crossover slopes with stereophonic deep or midbass, which doesn't exist. For purposes of discussion, I consider "deep" bass to be the first octave, or 20-40hz. To me, midbass is the second octave, or 40-80hz. Anything above that, I consider to be upper bass. Some people's definitions vary a little.

Mustang,

Call me all the names that you will. You have not shown ANY credentialed literature to back up your inference of being to hear stereo bass. Shall I assume you mean UPPER BASS, perhaps? Actually, Phil Newell IS an intelligent studio engineer and I have browsed his book a bit. Can you point to any particular passage where he claims that we can reliably perceive directionality in the low and midbass(subwoofer) regions?????? If not, kindly close the claptrap and peddle your subwoofer sales elsewhere.
Next you'll be talking about animal hearing experiments, right?......phhhht.

Read this thread and check back in a week or so:

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&read&3&4&

I have one sub and a good one at that.If someone hid the sub there is no way I would be able to tell where it was.How would having 2 subs change this?

Truthsloucher Your arguments are so lame and once again don't you find it ironic that among all the posts in all the threads nobody but Cnewlander (is that a friend or relative by the way?) agrees with you. To assist you in understanding more about the topic here, I suggest you read " Studio Monitoring Design: a Personal View, by Philip Richard Newell. Here is a quote that may guide you into a fuller understanding of what you claim we who are correct, "think we hear":

"The combination of (human) brain and ear have an awesome ability to resolve fine detail, orders of magnitude beyond our best measuring equipment"

Best of luck as you learn more about what you criticize.

Dear Truthseeker: My HGS-15 is 12db in the low pass and this fact makes a great difference in what you say.

Regards and enjoy the music.
Raul.

LOL Truthslayer. You're too much!!!

Truthseeker is correct.

If any of you folks could produce some type of coherent argument or refutation of the widely accepted acoustic theory (OTHER than your weak anecdotal evidence), I'd have more respect for you. None of you is particularly versed in crossover filter theory. None of you can hold a beginner's discussion regarding bass management theory. None of you can even admit that whoever convinced you to buy an extra sub for the purpose of achieving stereo bass separation RIPPED YOU OFF!

IF YOU CAN'T LOCALIZE LOW BASS (<80hz), YOU CAN'T HEAR STEREO...PERIOD!

Those of you who think they can, own cheap subs that produce significant harmonic distortion. This is DIFFERENT than the HARMONICS instruments naturally produce. An INSTRUMENT playing a 70hz note will also emit a first harmonic of 140hz. That 140hz tone will give directional clues as to its direction. A sub reproducing this 70hz tone will ALSO produce the harmonic....but at the outer band of its crossover curve..ie..24db's down from the original signal. The harmonics from your mains will COMPLETELY mask that of the subwoofer if your subwoofer is decent and has low distortion. THUS, if you use a decent, low distortion sub, with a 24 db/octave xover, the sub will play the 70hz tone, and the mains will provide the directional cues in stereo.

You can't deep bass in stereo no matter HOW much you THINK you can. The stereo effects are produced in your mains. Cross the sub over at no more than 80hz, use a higher order xover, and save the money you would have spent on an extra sub for CD's and DVD's. OR...give it to the dealer who convinced you to buy the extra sub...heh heh.

"You think, therefore you hear".

experiment: If you have a LOW distortion sub (like a Velo HGS or DD model) and have it crossed over at 80hz or lower, disconnect the mains. Then, close your eyes and have a friend move the sub around. See if you can point to the sub with your eyes closed. You won't be able to.

Raul,

I think you have your xover notion a little mixed up. The THX standard (they don't know anything about sound now, do they?!) xover is a second order HIGH PASS of 12db per octave at 80hz for the mains or satellites and a complimentary LOW PASS Linkwitz-Reilly (24db/octave) crossover of 80hz for the sub. This means that an 80hz tone will be down 12db's at 40hz in your satellites, and down 24db's at 160hz in your sub. That is why it is suggested that satellites or mains be capable of decent output one octave below the xover frequency.
And the reason you can locate the bass drum in a concert hall is because of the harmonics of its transients and the fundamental tone...which will be played in its full stereo glory BY YOUR MAINS. If that same bass drum could ONLY play it's fundamental tone (no harmonic), you WOULD NOT be able to locate it.

Go play now, children.

OR do some real research.

Truthseeker. Did you read this AA thread? There is only one other misguided person that agrees with you compared to the hundreds of others whom are actually correct about the 2 sub deal. I suggest you quietly walk away from this one.

http://db.audioasylum.com/cgi/t.mpl?f=speakers&m=139881

I listen to a lot of electronica and there is def info at or below 80 hz in stereo,even panned from left to right,,so i can see where running 2 subs in stereo would be a good thing,,one day i would love to try it!using just one sub drove me crazy!I decided not to use a sub again untill i can do it in stereo! Just my opinion of course.

Dear Truthseeker: +++++ " This whole stereo sub thing is nonsense. Hardly any info there. Hardly heard. " +++++

I think that you have a misunderstood of what happen in a real stereo subs integration to any audio system:

First, we choose the crossover frecuency ( say, 80Hz ) in the high/low pass filters. What this means?
That the main speakers will handle frecuencies over 80Hz and that the subs handle below 80Hz.
Normally, the self electronic subs crossover is a second order design ( 12db per octave ), this means that the subwoofers will work with frecuencies as high like 200Hz and now in the whole subs frecuency range will be stereo information.

Second, the subs reproduce not only the fundamental frecuency but their harmonics too where we can heard the left right info.

Third,it is not totally true that the CD recordings has only mono low bass. One of the CD advantages is that there is no problems for to record left/right low bass frecuencies ( in the LP is different ) and that's what the CD industry is doing: taking advantage of the CD medium.

Fourth, when you attend to a classical music performance you can heard bass sound coming from the left /right side of the hall, example: bass drum to the left and double bass at the right and this is exactly what we heard/feel when we have two subs in a stereo way at home.

Dear friend, I respect your opinion and that was mine.

Regards and enjoy the music.
Raul.

Truthseeker it's interesting that among all of the posts in all of the threads regarding the sonic advantages and superiority of a stereo subwoofer system, that you are the sole dissenter. That speaks volumes to either your ear or system. Here's a thought:
YOU'RE WRONG
Thank you an have a nice day.

Don't let the door hit ya.Where the good lord split ya!

Peace!

Actually, I'm using some extemely high end Radio Shack speakers for which I paid $34.95...which is probably more than what you paid for your Walgreens Sonicbox speakers.

You children obviously need to do quite a bit more research if you'd like to carry on an intelligent conversation about bass. Didn't realize I was playing in a sandbox....I'm outta here. :(

Maybe it's time to replace those Bose 901s Truthseeker. Move on up to a pair of Advents.
:-)

I can put my hands on each driver simultaneously
and feel them vibrate at different times on the same tracks. I suppose the subs only think their receiving a stereo signal as well. LOL

Yeah..no need to bother if you can't hear the difference.Just enjoy the mono string plucks.:-)

Good listening

I shall, my friend, and YOU enjoy what you THINK you can hear. :)

LOL my friend. Enjoy what you can hear.

Much of this conversation boils down to whether or not you believe that sub-80hz bass is directional. I don't believe that it is...and my experience has born this out. Therefore, the notion of stereo bass below 80 is meaningless to me. I suspect that most manufacturers feel the same way, and this is evidenced by their inclusion of the THX standard 80hz crossover point.

>>I suggest you spend part of your discretionry dollars on a good audiologist.<<

Do you have to work on being obnoxious, or does it come naturally?

Instead of attacking the message, you choose to attack the messenger. Instead of giving your own opinion about the sonic superiority stereo configured subs, why not show some pertinent research. If you actually DO do some research, you'll find that when multiple subs are recommended, they are never done so in a stereo configuration. Multiple subs ARE sometimes recommended by those who have the patience, expertise, and measuring equipment necessary to find the nodes, nulls, etc., but given the total number of possible sub placement permutations, I doubt that you are capable of such an installation.

Enjoy your stereo configured subs if you will, but please don't try to pass off your opinion as fact.

Truthseeker, I suggest you spend part of your discretionry dollars on a good audiologist. Perhaps that is the problem. Good luck and I'd be glad to help you.

Folks, as it so happens, I had a pair of Velodyne HGS-10 subs. Yes, a PAIR. I experimented with many locations...stereo, opposite walls, 1/3 wall, staggered, etc. I ended up stacking them and placing the stack just outside of a corner. Even played with a Behringer (very difficult learning curve).

Gmood1, what I meant to say is that there's hardly ANY out-of-phase information in the low bass regions where subs operate, and even if there is, it's NON-DIRECTIONAL...ie...it makes no difference. There is NO imaging at frequencies that low. If somebody thwacks a 50hz bass drum note, the imaging will come from the over-80hz transients located in your MAINS, and not the sub.

And btw, the Velodyne HGS series play with undetectable distortion in the first place, so the addition of the second sub served merely to increase overhead. The pair of HGS-10's has been replaced with a single DD-10, which will soon be upgraded to a DD-12.

Wc65mustang, my system is indeed high end enough to be able to discern a difference IF there was one. There wasn't. And my subs were as properly integrated as experimentation allowed. If I should ever decide to experiment with two subs again, I'll have YOU come over to demonstrate your special integration skills, but only if I can blindfold you to see if you can detect a difference. :)

On 99% of cd's, low bass out-of-phase info just isn't there...period.

Dear friends: THis is a very interesting link about the subwoofers number that we need.
This link was posted by Skushino on other thread. The conclusions are on the page 28, yes is a long history:

http://www.harman.com/wp/pdf/multsubs.pdf

Regards and enjoy the music.
Raul.

No question about Wc65mustang.

Regards and enjoy the music.
Raul.

Perhaps Truthseeker has not had experience with a high end system using a pair of properly integrated subs but the difference vis a vis a single is quite pronounced. I would suspect most audiophiles that have switched from a single sub to a pair will testify to this.

Truthseeker, not to argue...but I my understanding is that there is indeed different information that is sent to L/R subs when run in stereo. I may be wrong about that.
I know that my system (using Vandersteen subs) does not simply make a dual mono presentation. They are literally receiving only L/R signals. Are naysayers suggesting that in all recordings there is never low hz information sent to either left or right, but only both chanels? This may be, but I have never heard of it.
I have listened for years with one sub, then added the other. Whatever it does, using stereo subs alters the listening experience, especially since (and I don't care much if it's technically appropriate or not - it sounds great) the subs are directly behind the main planar speakers in the front corners of the room. To me, it's the ultimate way of integrating the subs with the mains.

Amazing how strongly some (Truthseeker - funny handle...) confuse opinions with experience. I was skeptical about multiple subs. My neighbor considerately lent me his sub to pair with mine, and the reponse was better - smoother, more toneful, more texture, less nodes. Multiple subs placed symetrically minimize room nodes effects. Multiple subs are NOT about more bass. Also, subs are NOT omni-directional. Try turning off your mains and running tones through your sub. Believe it or not, you will hear the sub above 200 Hz! And mine is an active 24dB/octave crossover at 60Hz.

There is so much BS on the Internet passed off as fact, by punters who never bother to learn for themselves. Warning - too much time in these discussion forums is dangerous to your audio health ;-)

scott

Dear Spacekadet: I'm not against your advisors that convince you to one sub instead of your original and correct idea of two subs in a stereo fashion.

The integration of subwoofers in an audio system is not only for abetter low bass performance: far from this, please read these links about:

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&27&4#27

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&31&4#31

Regards and enjoy the music.
Raul.