Home Theater Multiple Subwoofer Set-Up & Calibration Guide

R

Reginald Wallace

Enthusiast
I got the minidsp today, I took great care to watch the video of you and Hugo discussing how to use the dsp to balance my subwoofer setup. I also reviewed the instructions carefully on how to use the product beforehand. It came with the setting for gain control at 2.0 volts rms. I opened it up and changed the setting to .9vrms. I was able to change the sound of two of the subs by boosting the lower bass and cutting the upper bass through parametric eq. I also set all 6 subs at a Low pass filter of 80hz, and a high pass of 18hz. The Minidsp is amazing, powerful, and well worth the cost.
 
M

memanuel70

Enthusiast
Good question. For years, I always measured at the listening area for each sub. It was a pain to match levels that way. Then it occurred to me when reading Dr. Floyd Toole's book that what matters is how the subs balance with respect to the room NOT the listening area. Remember in order to take full advantage of standing wave reduction, all subs must:
  • be level matched with respect to each other
  • be properly placed
  • play exact same mono signal (LFE + all speakers set small)

The easiest way to measure each sub is to place the mic on the floor nearfield to the sub (within a few inches). If all your subs are single driver, then you can measure the SPL at the cone for each. You don't need to turn off the other subs if you do a nearfield measurement b/c the sound from that sub will dominate all others.

After you level match each sub, then go to the listening area and level match the main channels to the combined sub output. Once you flatten the bass of the subs, you can even boost their combined output a few dB over the main channels if you like.

Alternatively you can pick an equadistant point from all subs to measure their SPL individually but that can be difficult if they aren't all symmetrically placed in the room.
can we get a video on this process in the future?
 
Wellz

Wellz

Enthusiast
Hello, Gene.
I'm wondering what your thoughts are on using 3 subs (SVS SB12-NSD) versus just keeping 2 facing each other on opposite walls per the Welti suggestion? Trying to figure out what the benefit would be and if it's worth the added expense?
 
P

Pat Ted

Enthusiast
Hi,Gene.

Great article you wrote! I have a questions. I have a Denon X6400H and I am setting up a 7.4.4 dolby atmos (4 subwoofers). But the problem is that denon only have 2 subwoofers out (yes I can connect my sub with Y splitter). But still the AVR independent subwoofer setting is only for 2 subs. I have umik-1 mic dan REW, but no minidsp. my room is pretty much seal rectangular shape. My question is what do you suggest the placement/ setup for the subwoofers to get the best sound for 1 row seating (seating position around 1/3 from the back wall).

thanks,
Pat
 
lovinthehd

lovinthehd

Audioholic Slumlord
Hi,Gene.

Great article you wrote! I have a questions. I have a Denon X6400H and I am setting up a 7.4.4 dolby atmos (4 subwoofers). But the problem is that denon only have 2 subwoofers out (yes I can connect my sub with Y splitter). But still the AVR independent subwoofer setting is only for 2 subs. I have umik-1 mic dan REW, but no minidsp. my room is pretty much seal rectangular shape. My question is what do you suggest the placement/ setup for the subwoofers to get the best sound for 1 row seating (seating position around 1/3 from the back wall).

thanks,
Pat
Your avr can handle two subs (or two sets of) for independent setting of level/delay. So if four at least set each pair of subs that are equidistant together on the same pre-out. Some prefer mid-wall positions, some 1/4 wall position, some like corners for a bit more reinforcement. Very room specific. Might use the room sim feature in your REW software for mapping out nulls with subs in your particular room....
 
P

Pat Ted

Enthusiast
Your avr can handle two subs (or two sets of) for independent setting of level/delay. So if four at least set each pair of subs that are equidistant together on the same pre-out. Some prefer mid-wall positions, some 1/4 wall position, some like corners for a bit more reinforcement. Very room specific. Might use the room sim feature in your REW software for mapping out nulls with subs in your particular room....
thanks for the info. for corner placement dan 1/4 wall placement, I can get equal distant. But for midwall placement I don't think I can get equal distant from my listening position. And this is one of my concern if some how I check that corner placement or 1/4 wall position is not good, is there any other way around to set these subwoofers? since the AVR only able to set 2 independent subwoofers such as delay,etc.
 
lovinthehd

lovinthehd

Audioholic Slumlord
thanks for the info. for corner placement dan 1/4 wall placement, I can get equal distant. But for midwall placement I don't think I can get equal distant from my listening position. And this is one of my concern if some how I check that corner placement or 1/4 wall position is not good, is there any other way around to set these subwoofers? since the AVR only able to set 2 independent subwoofers such as delay,etc.
Well there's good ol' trial and error, what works aesthetically/where there's room for the subs, or even using REW (did you try the room sim, you don't need to measure for that, just play around with placement options).
 
P

Pat Ted

Enthusiast
Well there's good ol' trial and error, what works aesthetically/where there's room for the subs, or even using REW (did you try the room sim, you don't need to measure for that, just play around with placement options).
I will try the REW room sim. thank you for your suggestion.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Ninja
I think I would corner load all of them. Split the signals from the AVR. Sub out 1 to the front two. Sub out 2 to the back two. Audyssey will treat the front pair as sub one and the back pair as sub two.
 
P

Pat Ted

Enthusiast
I think I would corner load all of them. Split the signals from the AVR. Sub out 1 to the front two. Sub out 2 to the back two. Audyssey will treat the front pair as sub one and the back pair as sub two.
My sub is Yamaha SW NS300, it is a ported sub. and the port is on the right side. Is it possible to put in the corner, especially the right side corner, since the port will be directly facing to the right side wall.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Ninja
My sub is Yamaha SW NS300, it is a ported sub. and the port is on the right side. Is it possible to put in the corner, especially the right side corner, since the port will be directly facing to the right side wall.
Yes. It can go fairly close. 6” would be fine. Maybe I misunderstood. I thought you were implementing 4 subs?
 
lovinthehd

lovinthehd

Audioholic Slumlord
Yes. It can go fairly close. 6” would be fine. Maybe I misunderstood. I thought you were implementing 4 subs?
Or simply arrange the sub so both port and driver aren't wall facing....orientation probably won't make much difference, tho. Rule of thumb for distance I've seen most often for a port from a boundary is at least twice the diameter of the port....
 
P

Pat Ted

Enthusiast
Yes. It can go fairly close. 6” would be fine. Maybe I misunderstood. I thought you were implementing 4 subs?
Yes, I am using 4 subs. because of ported sub I cannot go to close too the wall on the right side of the sub ,because the port on the right side of the sub. Also I have a question, for 1/4 placement, how close is the rear of the sub from the wall usually?
 
William Lemmerhirt

William Lemmerhirt

Audioholic Ninja
Or simply arrange the sub so both port and driver aren't wall facing....orientation probably won't make much difference, tho. Rule of thumb for distance I've seen most often for a port from a boundary is at least twice the diameter of the port....
I always remembered 1.5xDiameter. Could very well be X2 though. I agree, that orientation won’t matter.
 

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