Hitta en intressant grej av Tom Nousaine
"Yes I have but to a much smaller degree (fewer rooms.) In my original work I discovered that subwoofers at standard left and right stereo locations all had serious problems because apparently they failed to excite the width mode in the room causing a serious suck-out between 45-55 Hz (room size 22x12x8.)
In a similar fashion the placement of subwoofers in what is now known at the ITU multi-channel locations had even more serious problems, such that 5 subwoofers in that placement were worse in frequency response and SPL than a single subwoofer in the corner.
You might check out the Harman web-site and investigate the Todd Welti modelling work on multiple subwoofers. In that work he suggests that mulitple subwoofers can optimize in-room response over a fairly wide range of seating positions BUT serious adjustment balancing EQ, Level and Polarity is required at EACH subwoofer location...meaning that unless you have his model there is no way to figure location and individual sub set-up relative to level, EQ and polarity from scratch. And the 1/3, 1/4 rules of thumb don't work.
He also suggested that the most improvement is gained by using 4 subwoofers. He also suggested that one good approach is placing a subwoofer half way down each of the 4 walls as a good starting point in a shoebox shaped room.
I tried this approach in my new room (irregular shape with open foyer and staircase with 18-foot catherdral ceiling) with a 13x23 basic footprint and discovered that such placement was problematic (introduced significant frequency response errors at basic listening area) and if you evaluated maximum SPL at 1/3octave frequencies compared to a single (same model) subwoofer in the best corner of that room that you get a couple dB-SPL less output with the 4
subwoofers.
I'm looking for a 15 x 20 x 8 foot shoebox to conduct more experiments on this line. I chose thi ssize room because a study of 251 North American Listenin Rooms conducted by one speaker manufacturer shows that 15x20x8 is the modal and mean average room size. Therefore experiments can be expected to affect more users in a meaningful way.
So as far as I can tell as of today there seems to be little reason to use
multiple subwoofers until we have some more data on what might work and what might not.
If you check back from time to time I'll keep you updated but I must warn you that progress isn't speeding along at breakneck speed. It's hard to find an unfurnished room (conference room or lie) for rent which is that size. "
HärIno i32s*(med ES filter), pY-4, cr80s, Nad 208, Rotel 1090, Pioneer 668, Denon 2106.
