Dear @gavman : That does not happens in my system due that the speaker woofers are not field coil design,my subs are integrated through a HP crossover filter and third the speaker woofersand my Velodyne buildmaterial are the same kind.
In the other side my room is different from yours, the standing waves occur at different places and the subs positions are different too. For example:my pair of sub's are firing not to rhe seat position but side to side each sub in front of the other sub. A unique sub's position.
So each one of us ahve towork according each one of us room/system chain.
R.

