I do that and I don't have room treatments or room correction. To get the bass right, a DBA does about 95%of the work; room correction and treatments do the remaining 5%.
Frequency response is everything!?...
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If its done properly, it won't matter.
At 80Hz the wavelength is 14 feet. Your ear needs to have the entire waveform pass by it in order to know the note exists, and a couple more to know the frequency of the note. In most rooms, by that time the 80Hz note has bounced off of every wall in the room. The lower the frequency of course the longer the wavelength. The take-away is that at this frequency or near it and at all frequencies below it, the bass is 100% reverberant.
This means that a mono signal will work as well as stereo.
Its the harmonics of the bass instruments that allow you to know their location; that information is supplied by the main speakers.
If the sub makes information above 80Hz or so it can attract attention to itself. So usually you want to cross them over well below 80Hz to avoid this issue.
I'm not using either. I'd like to be! If I do set one up it'll probably be stereo.
That seems right to me. DBA seems like the ultimate solution in the lower bass if you've got the room and speakers to pull it off, which is great because it's super hard to absorb enough energy down below 80 Hz. If you don't have DBA, then room correction and treatments can get you a long ways. I'm surprised at how well the room correction can work if you can get a plane wave launched off just one wall. The return wave can be effectively dealt with much better than I expected. I measured practically perfect impulse response below about 200 Hz down to 10 Hz in my previous arrangement. I'm now set up along the long wall in my room. This provides a wider sound stage but I can't get a plane wave started so there's reverberant energy in the room. With FIR filters I can get that down significantly at the cost of about 50ms latency. Surprisingly, even just minimum phase EQ can bring the decay times down and clarity up.
Well, I have tried mono and stereo subs and found that with digital I prefer stereo subs by a significant margin.
And according to Jim Smith mono subs for stereo should be avoided.
I once have considered the Gueddes distributed sub approach, but discarded it because I think that it is not a system compatibe with stereo subs.
According to David Geisinger we can detect phase difference across the head down to 40 Hz, and it gives us a different listening impression. I'm convinced it's true based on his headphone demonstration. It doesn't matter much to me because I've experienced both sensations in real listening environments so they both come across as realistic to me. If the bass is passing you front to back instead of side to side there is no phase difference. In any case you can't necessarily locate it but it feels different. A lot of recordings have mono bass, which he says does not sound like a real concert hall, which will almost invariably have bass that randomly creates phase differences across the head. He recommends running stereo subs 90 degrees out of phase, with one to the far left of you and one to the far right. No guarantee of frequency response with that, but just an increased likelyhood of some kind of phase shift across the head. A stereo double bass array could guarantee you smooth response and stereo bass when the recording has it.
Mono and stereo subs do not fix standing wave issues. I'm sure your impressions were correct. You don't get around this problem until the standing waves are eliminated.
Surely - I only managed to solve serious bass issues - the dips - with very large tuned membrane bass traps.
Using multiple distributed subs will function like an active Helmholtz resonator and will take care of both dips and standing waves. Used with group delay cancellation (GDC) that the best DRC programs offers, you have a winning combination.
The dips are caused by cancellation due to the outgoing wave bouncing and cancelling itself on the way back.
For bass traps to really be effective, due to the various frequencies involved in music, they would be most effective if dynamically able to move about the room with the music.
That is why a Distributed Bass Array is so effective. Standing waves are broken up, resulting in very even bass throughout the room. Its also insanely easy to set up compared to using DSP and bass traps.
My current room is a pretty good candidate for a stereo double bass array. It's a long room I'm playing sideways, so I could put an array on each sidewall. Four woofers per side should get things nice and smooth up to about 100 Hz.
How far up do you run your double bass array?
At 100Hz in most rooms the subs will attract attention to themselves. They must be placed assyemetrically to do their job. My main speakers are flat to 20Hz so I added two subs- one to my left and the other behind me and slightly to the right. They are crossed at about 50Hz.
So you're just doing the double bass array for the lowest bass? If so, then above 50Hz you're still going to need to deal with room issues, and that's where most of the music is. One good way is to make sure you are closer to your speakers than you are to any wall, and that they are closer to you than they are to any wall. It helps to have a big room. Unfortunately for me, I am closer to my back wall than I am to the speakers, which causes some pretty strong early cancelation between 100 and 200 Hz. That frequency range arrives later as two different reflection paths arrive at my listening position almost simultaneously after about 20 ms. I don't see any way around this for me other than to block or absorb that first cancellation path, and then absorb energy out of the longer paths as well. I experimented with absorbing the first cancelation path and had some success, but I need more. It's not the easiest thing to efficiently absorb 100Hz because the wave is over 10' long. If some of the energy can be taken out with room treatment, DSP can be pretty effective at cleaning it up further. The strong early cancelation is a problem for DSP because any correction signal also gets immediately canceled out. What it can do is just delay the entire rest of the audio spectrum by 20ms so that everything plays in sync, except you'll get a pre-echo of that early cancelation signal, which means you'll hear it loudly if you're not sitting where it cancels. I'd rather tackle a problem like that directly with room treatment rather than have DSP do something draconian.
The 1/2 wavelength cancelation is deadly. If you are further from a wall and get a 1 1/2 wavelength cancelation, it's likely not going to be as deep a cancelation, and that is pretty easy for dsp to fix effectively if needed because the correction signals can be significantly weaker than the original signal so it can sound natural.
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I have horns so I have controlled directivity. This allows me to minimize early reflections.
I found once I got the bass right that the mids and highs improved. This is because of how the ear/brain system has its own 'tone control'. That is why its so important to get the bass right.
I found once I got the bass right that the mids and highs improved. This is because of how the ear/brain system has its own 'tone control'. That is why its so important to get the bass right.
My lay opinion says taking the strain of off woofers and midrange drivers and oofers is essential.
I have horns too but I don't have directional control in the 100 to 200Hz range, except vertically because I've got line array horns. Vertically I can launch a flat wave but horizontally it goes wide coming out of the corner.
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