Best regards,
Mattias

Another important question is, what is audible? Low Q peaks are much more audible than high Q ones - Im not sure if this is the same vs frequency or different.

Must be some AES with data on this?I noticed last time I looked it was hard to find info on the

If the subs are placed within 1/4λ of the mains at the crossover point, then they will sum very well. They'll effectively be the same acoustic source. If not, then there will be some lobes that form in the room.

The thing is, wall reflections act as sound sources too. Each subwoofer in the room and each (wall, ceiling or floor) reflector acts as a sound source and they aren't going to be within 1/4λ of each other through the subwoofer band (or any other band, for that matter). Interaction between acoustically distant sound sources is nonminimum phase.

The only indoor solution that presents itself is dense interference. Use multiple point sources to average the sound field. CARA is room modeling software that can help you find what positions are best to place your subs.

Large bass response peaks typically occuring due to room interactions are interpreted by the ear as "fat" or "slow" bass, and the averaging-out effect of multiple displaced low-frequency sources smooths the in-room response significantly. The subjective result is better pitch definition because we can hear the notes in their proper relationship, and we might well interpret that as faster decay.

I have some experience in blending subwoofer systems with dipole speakers, and in that application multiple subs works very well. I can go into some detail about why if you'd like.

Duke

I ran into a production problem. A mistake was made in manufacturing the boxes, and that has delayed things.

My two beta-testers were happy and want sets, and one will be getting his next week. I did sell one completed set to a customer as I had just enough correct boxes on hand to put together one set.

Duke