Searching for matching(?) Subwoofer solution

Dear @audiokinesis : " I agree ".

I don’t know from where you take that " I agree ". I think that you can make some tests with two of your subwoofers crossed at 30hz and with different SPL on each test. Position at a normal one seat position and play music ( digital or analog ) with very low bass recorded information and then through several tests/evaluations lest us know if you can or can’t detect from where comes the sound you are listening.

Tests using first one subs at a time and then the same with the other and you can follow with both at the same time. Main speakers off(no sound.).

I already dit it and I think that only true personal tests we can have an answer. Every one with subs can do it. Please don’t ask my conclusions, we have to make our work/job.

R.

Btw, this is what I posted here about mono/stereo:


"""   Atmasphere that has first hand experiences on the overall recording proccess posted in other thread what oput true ligth on that mono/stereo subs issue:

""" Its not so much the limitations of the format as it costs a lot of money to pay an engineer to work a way around "out of phase bass". If you spend the time with the recording, you can usually find a way to master it without having to process it. But that takes time and at $500/hour most often bass processing is used. This is a simple circuit that senses when bass is out of phase and makes it mono below about 80Hz for a few milliseconds until the event has passed. This makes mastering LPs less expensive!
But CDs do exist where out of phase bass exists. This can happen because a microphone is out of phase with the rest of the recording when a bass guitar or bass drum is recorded. For this reason, the recording engineer has a phase inversion switch on every channel of his mixer but he may not have thought to use them.

If the recording is done in its entirety with only two mics, out of phase bass will not exist. """

@rauliruegas wrote:
"Position at a normal one seat position and play music ( digital or analog ) with very low bass recorded information and then through several tests/evaluations lest us know if you can or can’t detect from where comes the sound you are listening... Main speakers off(no sound.)."  

Well of course under those conditions (playing music through the subs with the main speakers OFF) you can hear where the subs are! This is because the lowpass filter on the subs are not brick walls.

But with the main speakers on, the output of the mains will be so much louder than the output of the subs that it will effectively mask the location of the subs, even if the subs are letting a little bit of upper bass/lower energy leak through.

The point is not whether there is an unrealistic test condition in which a distrubuted multisub system falls short. The point is, how does it perform when used under normal conditions?

Duke

audiokinesis:
"The point is not whether there is an unrealistic test condition in which a distrubuted multisub system falls short. The point is, how does it perform when used under normal conditions?

Duke"
Hello Duke,

     Yes, I believe that's the goal of most of us if not all of us: 
"How does it perform when used under normal conditions?"

Rauliruegas,

     As I've stated, the AK Swarm/Debra 4-sub DBA system performs exceptionally well in my 23'x16'x8' room and seamlessly integrates with my fast and detailed Magnepan main speakers (which for years have been infamous for being difficult to integrate well with conventional subs) for both 2-ch music and HT.  
     My main concern is music and I don't think I can overstate how well it performs on all of my CDs and it performs even better on my high-resolution 24bit/96KHz direct to digital FLAC music files.  
     This combination transports me to a fairly wide and deep 3D soundstage in my living room of the musicians and the recording venue, usually jazz or blues in a small club or Sound Liason's larger European direct to digital recording studio,  that's ultra-realist sound quality, I believe, can be largely attributed to the bass quality, impact and dynamics that's normally only experienced with music heard live and in person.  Thank you, Duke.
     I consider this state of the art bass performance but I understand that similar results can be achieved at a single dedicated listening position utilizing two high quality subs that are properly positioned and configured, like the approach you chose.  Here's a link to a Todd Welti, of Harman International, that confirms this:

https://www.harman.com/sites/default/files/multsubs_0.pdf

Later,
Tim  

@bdp24 asked:
"Is for the subs to be wired/operated in mono mandatory in a swarm sub system?"

Not at all.

"In other words, does the swarm not "work" (reduce/minimize bass peaks and nulls in the room) if the subs are run stereo?"

Works just fine in stereo. The only reason my commercial Swarm system is normally mono is, I can hit a more attractive price point by driving all four units with a single amplifier. As an option the Swarm can be supplied with a second amplifier.

"Or is it just a matter of that with a steep enough filter (say 4th-order, 24dB/octave), there is nothing to be gained by running the subs stereo?"  

If the bass is summed to mono on the recording anyway, which I believe to almost always be the case, then imo there is nothing to be gained by running the subs in stereo. But imo there is something to be gained (greater sense of envelopment) by using introducing a roughly 90 degree phase difference between the subs on the left-hand side of the room and the subs on the right-hand side of the room, and doing so requires two amplifiers, in which case you might as well do stereo. That way if you know you have a recording with true stereo separation all the way down, you can quickly dial back in normal phase using the phase controls on the amps.

"Is running two subs at the front of the room (in the neighborhood of the loudspeakers) in stereo, and the third and fourth in mono, a viable option? THAT would make using a shallower low-pass x/o filter on the subs (for whatever reason) possible." 

You can do that, but imo it doesn’t really make a shallower low-pass filter more feasible. Imo the main reason for using a steep low-pass filter is to prevent the subs from passing upper bass and lower midrange energy loud enough to betray their locations.   

If your subs have fairly shallow (12 dB/octave) built-in lowpass filters, you might try this: Use a lower low-pass filter frequency for the subs that are closer to the listening area, since these are the ones most likely to be heard as separate sound sources in the upper bass/lower midrange region. 

Duke