Axiom Home Page Forums General Discussion Advice from Axiom Owners Where to place additional subs?

Randy, one on the back wall and one on the side wall wouldn't generally be the idea. Middle of both side walls or front and back walls work to minimize the effect of room modes by being located at points where some modes are at a minimum(middle of the wall)and tending to cancel other modes by being opposite each other where those modes are in opposite phase.

Thanks JohnK,

Yes, I am planning on putting my 600 below my center screen on the front wall, and then get another sub for the rear wall next to the walk out door. What do you think would happen if I added a 3rd sub for the left wall? I would think 3 might be a little better than 2. Or I could put a 350 near each corner of the back wall.

Well Ian had said 4 subs is nearly ideal so 3 would be 3/4 to ideal. I would think the other 2 2/3 of the way down the side walls would work. You could also try one 1/2 way down and the the other all the way to the back just see which works better in your situation. After all it is about building up the low points so positioning is the key.

I think you are going to need to do some work once you get them. It is all just speculation until they are installed.

Although a third sub at that location would increase the overall sound level, it wouldn't have the mode minimizing effect that two at the middle of opposite walls have. I'd stay with two of the best possible(if you don't go to four....etc.).

While its true that the greatest change in flattening nodes occurs when adding the first sub, adding subsequent subs also contributes to smoothing nodes, as well as increasing headroom and lowering distortion. I found that going to 3 from 2 subs further improved FR but required tweaking placement and phase again in all the subs.

The Harman study does provide idealized locations but the exact location in Randy's room will be influenced by the location of his furniture and its slightly irregular shape. That's why the SMS-1 mic technique makes finding the ideal placement a snap.

It also seems to me that if there ever was a case to be made for colocating a pair of subs, its Randy's huge room. One alternative is to colocate a pair of 350v3s for an extra 6db output from coupling. A pair setup that way would provide max SPL of 113 anechoic, 124 db in room according to the Axiom stats. Along with the 600 that should give give you enough woofage for that 9000cf space and still give you some benefit of smoothing FR.

Can somebody refresh my memory, what is the difference between the EP350 and the new EP350v3?

I may be oversimplifying but if the main benefit of two subs on opposing walls is wave cancellation of the room modes caused by reflections resonating after the first direct sound was heard.... would this improvement be mostly negated by large items of furnature between two opposing subs. A couch for instance?

I think the answer is Yes as evidenced by the fact in these example rooms and graphs, the furniture was always shifted in the example pics to allow the subs to have line of sight to each other, when used in opposing configuration.

Hearing things is hard work....

Example rooms and graphs.

The new 350 now uses the EP500 cabinet and is 300 watts, up from 200(?). It also has a "nifty" circuit for extra bass output.

Thanks Mark, the reason for the question is that I had a ponder to drag the old 350 out and connect it up with the 600 ... don't know if that would work or not. Seems like somebody (Brent?) told me it would not be a good combination some time back.

I believe it was framer2180 who has both versions. Try PMing him as to the actual acoustical differences.