Distributed Bass Array configuration

Of course not. Especially not since I agree, at least in my disdain for experts, and credentialism in general.

What gets me is what I said- asking very specifically for the advice of people with a DBA. But then when you get it you go with the advice of someone who not only has no DBA, but knows nothing about them, and in fact runs around threads like this where his lack of knowledge is expressly not requested, and spreads his bad advice as if he actually knows what he's talking about. 

I had a friend, an expert fisherman. This guy knows everything about everything when it comes to fishing. When another friend was looking for advice on a boat I naturally referred him to my fisherman guy. Who said sorry Chuck, I am not gonna help him. Why, Larry? Nobody knows more about this than you. "Because I don't want to waste my time" and then proceeded to tell me all about people he advised who then ignored everything he said. So he doesn't do that any more.

Me, I am more selective. No hard feelings. No more help either. I'm sure you understand.

Its not just me by the way. Read the thread. You disrespect Tim as well. So basically the only two guys to give you what you ask for you disregard and disrespect. 

Duke- This is what I was talking about, and once you understand that, it will be clear why a small change in gain on the subwoofer amp typically results in a larger than expected change in perceived loudness. Or, to put it another way, why it takes a while to dial in the gain setting on a subwoofer amp.

MC- Gradually, over time, I make really small level adjustments. Really small. Like I turn the knob but about half the time not really sure it did anything. This works because the meaning of the equal loudness contours is we go from being relatively insensitive to bass at low volume to hyper sensitive to bass at high volume".

golfnutz- The difference between the two is: MDS.

golfnutz- You’re twisting it around MC, the whole purpose of level matching is to prevent you from trying to figure out what the volume on the subs should be. That’s why its called level matching.

If you say so. I prefer to say it is to achieve a seamless and pleasing presentation. Please read Duke’s posts above.

Why is there never any mention of level matching these DBA systems with the main speakers using an SPL meter?

There is. All over the place. I've never done it. I listen with ears, not meters. So why would I care what a meter wants?

Otherwise, wouldn’t it just be guessing what the volume level should be on the subs?

Is that really what you think? Do you "guess" what volume level you like? "I think I'll try 12 today. Wow that's way too loud! Guess I'll try 4?" Is that what you do? Of course not. You know perfectly well what volume you want. So why would subs be any different?

I'm almost always talking about my DBA in terms of music. But I have to say, the effect with movies is if anything even more impressive. A good movie soundtrack through a high end stereo with a DBA is really something.

I think that if the DBA system is integrated properly it affords one the ability to integrate bass effortlessly, no matter the listening level, which is highly appealing to me.

The beauty of DBA is the "integrated properly" happens almost automatically. With one sub it is impossible, the peaks and nulls are unavoidable and draw attention to the bass. With four they are so small and smooth the bass disappears, the subs disappear, and all you are left with to "integrate" is their level. 

When it comes to that, there is no escape from the reality of human hearing. Equal loudness contours are a thing. DBA is no magic bullet.  

It does however get a lot closer to what you described. With normal no, one, or two sub bass the really low bottom end either falls off to nothing, or else you have way too much above that. Either way you notice big changes with volume. With a DBA the contours are still there but nowhere near as big a problem due I think to the smoothness factor. 

What I did, once the initial phase is done, was listen to a lot of different music at my normal levels. I abhor meters. Most of the time I listen at a nice satisfying volume level. Sometimes not that loud. Occasionally I listen Supertramp Loud. Gradually, over time, I make really small level adjustments. Really small. Like I turn the knob but about half the time not really sure it did anything. This works because the meaning of the equal loudness contours is we go from being relatively insensitive to bass at low volume to hyper sensitive to bass at high volume. The same 2dB change in other words seems completely different (a lot more) from 98 to 100dB than from 88 to 90.   

Took a while, but most of the tweaking was in the first few weeks and now it is pretty close to what you said, effortless no matter the listening level. Never quite gets there, but close enough I never give it any thought any more- until it comes up like this. 

Big room + big DBA = killer bass!

By Jove, I think he's got it! 

Only what you should do is add 3 subs to your REL to make 4. The number of subs is far more important than what kind. I thought, according to the research, each additional sub adds proportionately less. So my plan was to build 4 to replace my one Talon Roc, which would then be sold. My plan was going fine. Removed the Roc from the room, put the 4 subs in, heard the vast improvement.

But then before selling the Roc I thought what it would be like, put it back in, and there it stays! Either it was more than the predicted 25% improvement, or 25% is more than you'd think. Either way it was big enough to keep me running 5. Granted the Roc is two 12" monster magnet woofers in a ported isobaric cabinet. A much better quality sub than the ones I built. So quality does count for something. But numbers count even more.

A lot of the challenge is that while there is no stereo bass in the bottom octave or two, it does sound as if it is stereo. The drum whacks in Bird on a Wire, each one has a definite location. The hall ambience and cannon on Tchaikovsky 1812 are all incredibly precise. When people think of mono they think of Beatle's and other mono records where the sound all seems to be coming from a sphere in between the speakers. That is NOT what we are talking about! This bass does not sound as if it is mono. Not at all.  

However, rest assured, it most certainly IS mono! Anyone harboring any doubt whatsoever is welcome to come and hear, I am happy to demo, and you will hear absolutely zero difference when my DBA is run mono vs stereo. Zero. Nada. Zip. None. Because it is all mono! 

This actually even makes sense, because when you think about it, how else could it be? The wavelength of these low frequencies are so long, that in order to be picked up as stereo the microphones would have to be located a hundred feet or more apart. Even then, our hearing simply is not sensitive to timing at this degree of precision at this low a frequency. We don't even hear less than a full wave! Don't even hear it! 

This is where I think a lot of this comes from. Everyone is familiar with midrange and treble. Everyone knows the importance of phase, timing, etc. This is all goes right out the window with low bass.  

Also by the way with ultra-sonics. Super-tweeters, 40kHz, 60kHz, we cannot even hear. Yet they affect the sound in such a big way it changes our perception of even low bass!  

The mind is a strange and endlessly fascinating thing. Hearing is not just mechanical. We like to use a microphone as a metaphor for how we hear. But that is not all there is to it. The phenomenon of hearing is far more complex. The mind plays a vital role. Try and get your mind around it. 

That is a great quote and relevant Tim, and thanks for saving me the time of reading the whole interview. Your last comment is one of the clues that helped convince me DBA was the way to go.   
The only times we experience truly low bass in normal life is in very large to wide open spaces. For me it was always one of the coolest parts of going to a rock concert, that vast space feeling of bottomless bass. This was always missing, particularly in orchestral works, because even if it is on the recording the system simply cannot reproduce it at home. Even if the system response measurements look good still there is always the room that ruins this.   

I'm sure you know where I'm going with this. One of the more surprising things with a DBA is the enhanced feeling of envelopment. People have commented on it with my system. It is very deceptive. First, because no sound whatsoever appears to be coming from the subs at all. But also because the low bass that triggers this feeling isn't even heard or sensed as bass at all. It has no pitch, nor location. It has no attack or slam, no harmonic, no tone at all. Yet somehow it creates this ineffable feeling of being in a huge space.  

Nothing else does this, at least not to this extent, and I have heard some pretty awesome gear in some damn fine rooms. Yours as I recall are one per corner. Another one has this plus one way up high near the ceiling. Mine are along 3 of the 4 walls. It seems to work well almost regardless of how the subs are laid out.

So in spite of terrific testimony you asked for- actual experience- you are playing around with the advice of one who has no actual experience. Par for the course. Oh well.

Moving along... In the interest of helping others following along, here is why crossing over the mains is self-defeating and a bad idea.

The key to excellent low bass is lots of sources of low bass. To the extent they put out low bass this includes the mains. Also more different locations helps, and while subs are almost always very near walls the mains are almost always several feet out. So crossing them over eliminates two very beneficial bass sources. In a realm where numbers matter far more than anything else this is known as a own goal.

Frankly and with all due respect you have no way of saying you got from 90 to 95% for the simple reason you have no idea what 100% sounds like. For sure the one you are taking advice from has no idea, he has never done this.

Once again I am perplexed and vexed at one who specifically asks for one thing- "those who use a DBA"- then turns around and follows one who not only does not use a DBA, but talks down anyone who does.

https://youtu.be/0t2pWUWE1Y8?t=8

Oh well, plenty of others willing to listen and learn. No point wasting any more time here.

hleeid-

@mike_in_nc  -

Firstly, heed the advice from MC/Noble101/and especially Duke LeJeune.

Secondly, I will divert from phase, crossover frequencies, gain, etc. and instead share my experience regarding subwoofer placement.

I am running four subwoofers (yes, the AudioKinesis Swarm). Two are mounted up high facing the ceiling. Their heights vary with one 12 '' and the other 18 '' below the ceiling.

Duke mentioned in an earlier thread that any subwoofers mounted above the room mid height contribute to the vertical plane, thus further reducing standing bass nodes.

My A/B testing (4 on the floor vs. 2 on the floor with 2 up high) in 2 rooms (10 x 12 minus closets and 12 x 16 living room) at my previous house along with over a year at my new house (also A/B testing between a 13 x 16 vs. a 15 x 19 room) all clearly confirm a noticeable all around improvement.

Hope this is helpful to you!

mike_in_nc, Hope you are paying attention (to the whole thread) because this is typical of what happens every time. A small number of us have experience and knowledge. A whole bunch more talk as if they do. Sift though the chaff to sort out the wheat and you will be fine.

Thanks b_limo it is very clear, yet evidently still not clear enough on one point: there is no such thing as stereo subs! Because, there is no such thing as stereo bass, at least not below 80.

This will be like, I don’t know how many times clarifying I am losing count. And apologies in advance for shouting. But when everything is done right it SOUNDS AS IF the bass is stereo, BUT IT IS NOT!

If I have one weakness it is not bothering to keep track and being able to reference every tiny little thing. So times like this I forget where it comes from. But some big engineer paid a lot of money did an in-depth study of a wide range of recordings and found none of them had stereo bass, and anyone interested can look it up.

Another good one to look up is my mega DBA review. Mine uses two Dayton amps partly because at the time I wasn’t sure and thought two might be better. Just in case. Once I had them though some of the first things I did was to try running my new DBA in all possible configurations. I went through the gamut. 4, 8, 16 ohms. One amp mono. One amp stereo. Two amps mono. Two amps stereo. Played with phase. Tried all the time waster put the sub in a chair while you crawl around on the floor. About the only thing I did not try is the even worse stuff that requires a microphone. When the day comes a mic is better than my ears, take me out and put a bullet in the head, I’m already dead.

BUT, and this is a very big important BUT, it sounds as if it is. Why? The answer can only be that information above the low bass is somehow integrated into one seamless whole. This happens in the brain. Not in the ears, but between them. For proof look no further than the Supertweeter thread where everyone who tries them says two things: 1. they can’t hear them- too high frequency- and 2. they improve the bass. So how does ultrasonic 60kHz improve bass way down below 60Hz? You tell me. But it does.

1. Doesn't matter. It is all mono. Proved it by running both ways. No difference. There is a lot of BS around subs. Stereo bass, for example.

2. This one is a misunderstanding of phase. The phase of the subs in relation to the mains doesn't matter. Timing does not matter. The importance of phase is in that the output of all the subs with the room, it all interacts. Each sub has its own set of room modes. These room modes move around when the sub is moved around- or when the phase of the sub is moved around. 

If you do your sub setup, place the subs asymmetrically at different distances from the corners, set crossover 80 or lower, and then set level, you are basically done. These are the big ones. Phase, I have it on my Dayton amps, as well as on my Talon Roc, and it is easily the lest significant of all the things you can do. 

All my subs by the way fire into the wall from about 2" away. They are asymmetrical, and I never have any idea where they are or indeed if they even are on at all! No one does! Yet the bass is beautifully 3D and seamless with everything else.