Rules for matching subwoofers to room size

One other situation that would allow you to hear the location of a subwoofer would be if the system was poorly designed, such that the subwoofer had high harmonic distortion (or a buzz or rattle) or port noises. Drew Eckhardt mentioned this in his post above, and he is absolutely correct.

Thanks, helpful.

Audiokinesis...I think it "really does matter" that the thump of the drum and the higher frequency percussive sounds come fromn the same location...for phase coherency if nothing else. Contrary to what you said I think that most subwoofers have 24 dB crossovers, not 12. Mine do.

Of course I have heard all your theoretical arguments before, but perhaps others have not. My bottom line is that Knownothing can decide for himself when he gets the SW.

Eldarford, one of the problems here may be in our definitions of terms. For example, you use the term "thump of the drum", and to me that implies harmonic content sufficient to allow pitch to be discerned. The pitch of bass instruments can be difficult to discern without the harmonics; try listening to a properly low-passed subwoofer with the mains off. Anyway if "thump of the drum" includes harmonics in the region where the ear is good at judging directions, then yes where those harmonics originate from does matter.

Phase coherence has become a buzzword, but is actually a relatively low priority from a perceptual standpoint. You see, the ear does not hear waveforms; rather, the inner ear deconstructs and processes incoming sound energy in a complex way that changes with frequency. The ear is especially poor at resolving phase in the bass region, as can be inferred from one of my previous posts. But the ear is pretty good at hearing
certain types of variation in frequency response, so I would argue that there's where our attention should be focused if high quality is the goal.

My bottom line is that acoustics and psychoacoustics can be highly non-intuitive, but quite a bit of real-world applicable research has been done.

Audiokinesis...You are correct about phase coherency being overrated by audiophiles. I threw that out as one plausible explanation of what I personally hear even if you don't :-)

Many years ago I read an interesting observation about an experiment involving phase. An irregular waveform like a steady audio signal can be subjected to Fourier analysis and represented by a collection of sine waves with different frequencies and amplitudes, and phases. If enough of these frequencies are used the original time domain waveform is very accurately reproduced. You can play back the collection of Fourier components (sine waves) and listen to them. They sound like the original irregular waveform.

Now comes the interesting part. Arbitrarily change the phases of the Fourier sine waves. Although the same frequencies and amplitudes are present the reconstructed time domain waveform is now quite unlike the original, but the sound does not change. This implies that our sense of hearing functions in a rather complex and unexpected way.

As I said, I read about this experiment, and did not hear it for myself. I would sure like to.