I’ve always thought that any ‘automatic’ setup of a subwoofer is a difficult thing. The equipment can’t use too short a burst sample because the frequencies of interest are low. On the other hand, once the sampling time becomes long enough, room effects will be measured as well. Of course the listener is immersed in room effects while listening, and most frequencies of interest in playback material last long enough to involve room effects, so taking room effects into account while measuring is definitely worth doing.

Most rooms are sensitive to various standing waves in the lower bass region, and this presents another difficulty. I’ve sometimes seen great variances by starting a test signal and walking around the room with an SPL meter. Just placing the test microphone in a slightly different place can yield varied results. If the device you’re using doesn’t take into account multiple measuring points, and you’re not going to go with TrueRTA or a similar approach, it may be helpful to run any testing procedure several times, moving the microphone between each test and writing down the result. Afterward, ignore the very highest and lowest result, and manually enter an average or median value of the rest of the results.

By the way, welcome back Altec!