Axiom Home Page Forums General Discussion Home Theater Thoughts on multiple subwoofer placement

Well, hopefully I'll have two subwoofers soon. I'm still a little hazy on exactly how to optimally place two subwoofers. The popular recommendation of mid-wall front and rear or mid-wall on the sides applies mainly to closed, rectangular rooms, correct? Right now I am in a room with openings into other rooms, and it works out that the subwoofer crawl indicated nearly mid-wall on one side as a good place, but I don't think the opposite wall worked too well. However, I'm curious if you even want to place the second subwoofer according to the subwoofer crawl for the center seat. Will the bass be more even throughout the entire listening area simply by virtue of having two subwoofers placed in different parts of the room? I guess I'm asking a complicated question that probably won't have a clear-cut answer.

The layout for the basement area I'll have my system in (eventually) will be an odd shape, so I'm just trying to get a feel for what the general advice is. Place them both according to the single subwoofer crawl? Place them both mid-wall on the sides, even in the non-ideal layout? Try them all and graph them all and leave you all alone? Why would I even give you that last one as an option?

Charles, I don't know what the right answer is for an odd shaped room. . .

I have two of my subs about a third of the way on two walls and the third is tucked away in the front right corner.


I should add, if I was going to take one away, it would be the front right one.

Is that also your weakest sub?

Yes, it's one of the 10" sealed subs.

Man, now I'm hungry for a sub sandwich. I know about proper placement of those.

Wait, I shouldn't threadjack my own threads.

You're just making it easier for the rest of us. . .

I'd recommend if you get a party sub, to place it on the dining room table.. or if you have a long counter.

Now I need a foot long Sweet Onion Chicken Teriyaki.

CV, I think I would use the subcrawl to position the first sub and then I would try to graph out various placements and from different seating positions for the second sub, to see where the best position is for flatest response.

Charles, if you have any way to do so, I'd recommend you set up the REW software so that you can use it in your room to find the best positions for the new subs. The sub crawl is a good start, but since you're generally just estimating bass response of a single frequency while doing this, it's hard to know whether a given location provides the smoothest response or just the loudest response at the frequency you happen to be using for the sub crawl.

My (unconventional?) advice would be to start with placing both subs where they are most conveniently-placed in the room. In theory, with two subs, placement is going to be less important than with just one since the idea behind two is that they work to attenuate the effects of room peaks and nulls.

Based on that, I'd start where you want them and run a frequency response (FR) curve using REW from your main listening position and measure the results. Then without moving the subs, experiment by changing the phase on one, then the other, then both subs, and determine which combination gives you the smoothest response at your main listening position. This should be your benchmark against which you test any other placement options. (i.e. since this is the most convenient placement for your room, to move the subs to other locations which would look awkward or be less ideal than where they are, another position would have to have FAR better FR to justify making that move and dealing with subs sitting in the middle of the room, weirdly placed on sidewalls, etc.)

Once you've done this much, experiment with a couple of other options. Try the middle of two opposite walls if your room allows, or try opposite corners of the room (my current setup).

If/when my 800 arrives, I'm planning on moving both subs to the front corners outside of the M80s. That will be the "ideal" setup from which I create my benchmark readings. This choice is mainly for looks & balance. i.e. I think it'll look extremely odd to have an M80 and an 800 on one side of the room and just an M80 on the other side of the screen.

If I can't achieve the results I want from there (and using the BFD equalizer), I'll try going back to opposite corners or some other combination that produces flatter response than the way I'd prefer them to be set up in the front corners.

Just resign yourself to the fact that it's going to take some time to get right, and try to have fun in the process (it shouldn't be hard to have fun with it!). We'll look forward to hearing/seeing your results as you experiment.

Jason