Keta- I hear ya , but I would have some questions. You say you have full range speakers. -3 dB point is 20 Hz? *And*, you have tested that with a calibrated microphone and a software package something like ETF so that you know that you are only getting direct, and not reflected (bass augmented) sound? I know that a lot of manufacturers put forth the claim that they have "useable" output down to 20 Hz, but that is something like - 10 dB, not - 3dB. -3 dB at 20 Hz speakers do exist, but they are rare and do cost some denaro.

Even if you do have full range speakers, crossing them over *will* help them sound even better because driving low freqs is not easy. (I bet BoB and SH can phrase this better than I can. Better dynamic range in the the midrange.)



Ahhh, but you are balancing the valleys of 1 channel with the peaks from another? That's not right. The goal should be flat response with *each* sub, and not with all three going. Otherwise for example, you're filling in the valleys from say the left channel speaker with bass from the right channel. That's different content!

The best rule of thumb I ever came across for multiple subs? Stack them all in the same place. Whether it's a corner, or along a wall.