How do I "compromise" speaker placement

Yes Bob, very similar to that, but not exactly. With phase you can have speakers literally pushing a pulling against each other. With IMD it's more about timing of the direct signals arriving in-phase but not at the same time. It's easiest to imagine thinking of a mono signal through a stereo system. It'll come equally out of each speaker, so time alignment of the two speakers must be precise or you hear an inbalance and/or a smearing.

In an anechoeic environment that would be simply time alignment, but then you add the room interaction and the nodes and you do get cancellation, emphasis and timing all rolled together. In my experience, you perceive it as added harshness and loudness. When it's minimized (I doubt that it can be eliminated) the loudess measured with an SPL meter is the same, but your perception is that the loudness declined. It's amazing. You find yourself comfortably listening to music 12dB or so louder.

My understanding is only as a layman and from the little I've been told by Rod Thomson based on his training by Sumiko.

Dave

Hi Dave, you said, " It's easiest to imagine thinking of a mono signal through a stereo system. It'll come equally out of each speaker, so time alignment of the two speakers must be precise or you hear an inbalance and/or a smearing."

You you are saying then, that the first issue to address is exact measurement of speaker to ear distance and extrapolating that out, probably exact placement of speakers and listener within the room? To avoid odd arrival time of the original sound and reflected sound.

Is that correct?

Bob

No Bob, it's sound pressure level instead of distance. With the sumiko Master Set the distances are rarely equal, because of the room annomalies. The Master Set takes into account multiple interactions at once.

Dave