stereo subwoofers


I am considering buying two Velodyne DD10+ subwoofers to complement my fact 12s.  I gather that they come with a calibration system which allows the subs to "listen" to the main speakes and the room, and then tailor their output to this.

My local dealer said that he would normally calibrate one sub, then attach the second sub and calibrate that one.  My gut feeling is that this would create a setup that is not balanced. 

Has anyone done this kind of setup?  If so, did you calibrate both subs at the same time or one after the other?

Many thanks.
Calibrate each sub with its single, main speaker separately.

Bass traps such as the GIK Acoustics Soffit traps will improve the results if placed before EQ is done.


I am not sure this is right. The peaks are not peaks from one single speaker, but from both. Hence you want to benefit from the smoothness of the combination and equalize the joined output from the pair, I would think. Anyway, Dspeaker and others recommend playing dual subs in mono, and equalizing them together. However, I have no idea how to do that with two eq units. What does Velodyne say?