Multisub: It's not just for multiple Rows!

[@poleepwka]

In a setup with multiple subwoofers and a processor equipped with Dirac Live Bass Control, is it better to let Dirac handle the alignment and EQ of the subwoofers from the start, or should I manually align and roughly EQ them first before running Dirac? I am already using a DSP for my DIY subs to apply a low shelf boost and also a LPF. Currently, I have 4 subwoofers but plan to add more. My processor has 5 subwoofer outputs. From what I’ve understood in Anthony Grimani’s videos, most professional calibrators align subwoofers manually and also EQ, using only one output from the processor. What approach would provide the most optimal bass performance?

[@ruvamsi]

Hopefully Matthew picks this question, but my understanding is it's best to manually time align the subs to each other and then let DLBC time align the subs to the mains. EQ seems to be trial and error based on preferences

[@johndaddabbo9383]

@@poleepwka If I may please: 1. If you have the means to Time align all the Subwoofers most definitely do so. 2. If you also have the means to then Phase align all of the subwoofers, again most definitely do so. 3. Lastly, if you have the means to EQ, do so judiciously. For example: A.) to address any significant dips - using above #s 1 & 2 and also Subwoofer placement / MLP placement in order to minimize any global Dips in the Bass frequencies. B.) Peaks, unless excessive I would leave those alone and IF excessive AND at least an octave below the Subwoofer's likely crossover point, bringing down any excessive peak only as much as to not cause any further Dips and also no impact to #s 1 and 2 above. OK, well that's just one man's opinion 😀

[@PoesAcoustics]

Thank you for supporting my channel! I'll be recording a video and answering your question shortly.

[@johndaddabbo9383]

@@PoesAcoustics Good morning Matt, feel free to use any portion of my above answer in your response video. Please note that I only charge $1 an hour with a minimum of 1 million hours per-session 😁

[@mdelcomyn]

I just went from 2 to 4 subs and found it to be well worth it. I wish I had done it sooner. And I base this comment only on my experience in the MLP! 4 > 2 all day. Great video as always. Thank you.

[@gjhunter9326]

Thank you very much Matthew, your answers were right on point for me. The term multiple spatial positions vs multiple rows clarifies my thought process. Since single row seating mostly differs in the lateral position (width) relative to the MLP, whereas 2nd row seats might differ from the MLP in depth, height and width I wasn't certain so thank you for explaining. Also your point about raising the subs off the floor causing room modes due to floor bounce is also helpful. I've had my subs 1/4 distance in from the side walls and 1/4 up from the floor on stands so I'll set them back on the floor and measure again. I hadn't thought about placing two subs in the midpoints of front/rear or side walls but that would be interesting to try. I ask these questions because I've been trying to decide whether to upgrade the two subs I have or to just add two more of them and sounds like the latter may provide the best result. It's very clear on the 1 vs. 2 sub advantage, but wasn't quite as clear to me in the 2 vs 4 in my medium-small space. This was very helpful. Regarding the acoustic treatment question, thanks again for the info. Sounds like I'll need to change things up a bit with less absorption. Until my current build, my space has been dual purpose for critical two channel listening and home theater with priority going to 2 channel optimization, so my comment about 1st reflection was for the front channel side walls and ceiling. I then had diffusion on the front wall behind them and then absorption behind the center channel, which was below a non-AT screen. Now I have a dedicated theater with LCRs behind an AT screen so needed some clarification. Would a absorpion/diffuser combo product be appropriate on the wall behind the LCR or would you suggest pure absorbers behind the speakers and then diffusers between the absorbers perhaps? Thank you again Matthew, really appreciate your efforts and insights. GJ

[@pauledwards8721]

Interesting about 2 sub placement and not using corner positions. I went with Front Left and Rear Right. Will think about front middle and rear middle if possible on my next build.

[@matta9316]

Love your channel!

[@gbye007]

Ed Mullen of SVS recommends front and rear diagonal corners for 2 subs.

[@FOH3663]

Acoustic polarity ... If only 2 subs are being implemented, splitting the center lines; front to back, side to side and above and below. So yes, that'd result in diagonal corners, top and bottom.

[@anoopk1771]

great video as always. could you please mention the issues of mounting the subs to the ceiling?

[@melraine919]

Thank you for the info 👏🏼👍🏼🏴󠁧󠁢󠁥󠁮󠁧󠁿🇬🇧

[@joshuamarble3518]

Hey Matthew, thanks for all the info on bass placement and acoustic challenges. You mentioned 2 sub placement at middle front/middle back or middle sides as well as quarter front or corner placement. How do you feel about 2 sub opposite corner placement. That being front left and back right corner. I have two Perlisten R18's and am limited where I can put these beasts.

[@andrewskaterrr]

You end up with a half and half good/bad. I actually tested this at my buddies house and as expected it gave us 1 good right seat, ok MLP, and terrible Left seat. It was better with both up front.

[@petermuwanula7142]

Good video. Thank you sir

[@PoesAcoustics]

Glad you found it useful!

[@satii24]

Awesome video!

[@PoesAcoustics]

Thanks!

[@bingdong8571]

for 2500 sq ft 2 or 4? 24 sounds more optimal to me, or maybe 30 if u can fit it

[@jamiet74]

He said cu ft ...cubic feet.. big difference,2500 cubic feet is a fairly small room

[@bingdong8571]

@@jamiet74 ohhhh, my bad, 2400 or 3000 if u can fit it than.

[@garyharper2943]

Remember when the woofer was built in to your two speakers , no placement issues then. My Cerwin Vega AT 15’s have plenty of bass.

[@paulgyro]

Ah Only if that were the case. Rarely can you place full range speakers in the ideal location for bass reproduction. Room modes are your enemy.

[@johndaddabbo9383]

Stated another way: almost invariably a full range tower speaker placed for optimum Stereo imaging and Soundstage will then have poor bass performance, even if only one server suckout (for which you will be unable to fix). If you instead place those full range Tower speakers for the best Bass performance, you for sure will not have them in the proper position for the best Stereo Imaging and Soundstage. Hence in many rooms, but not all rooms, crossing over the main tower speakers at 35, 40, 45 or even 50 hertz may be the best way to go.