I've got two subs with nearly identical frequency response curves as measured by myself, the only difference is one is -3dB at 30hz and the other, larger one is -3dB at 18hz measured outdoors. Both subs utilize the exact same driver and cabinet design, just one is bigger, think of it like matching a pair of bookshelves to a set of tower speakers from the same brand and line of speakers.
If I place a single sub on the front wall near a corner I get the most even response as far as notches in the frequency response goes but I also get a 9dB peak at 56hz, which pushes the -3dB outdoor response up from 20hz to 35hz in room, since everything centering around 56hz is 6-12dB louder. If I place the sub at the back of the room about 3 feet away from the wall along the side wall the 56hz peak is eliminated and everything from 50hz-100hz is super flat, however, everything below 50hz behaves erratically with lots of cancellations. I have been able to EQ the response flatter with the single sub on the front wall but only cutting the problem frequency wasn't enough, I had to boost the sub 50hz frequencies in order to get them more level since they were buried as much as 12dB below the peak. Because I'm boosting the most power hungry frequencies as much as 6dB I am concerned with the amplifier running out of headroom or the driver running out of xmax at high volumes.
My idea is to place the smaller sub near the side wall and keep the larger sub on the front wall and utilize an external crossover at 50hz, sending everything above 50hz to the small sub and everything below 50hz to the big sub. Of course I would level match and EQ any significant aberrations between the subs.
Has anyone done something similar or have any thoughts on this?
