Rules for matching subwoofers to room size

IMHO, If there is any stereo information below 70 Hz (and with an LP there won't be) the SW will be easily located.

I would stay away from 10" subwoofers which achieve their SPL by extreme cone excursion that results in distortion.

A quality 12" or 15" driver will have a much stronger magnet/voice coil than a 10" driver, and so can handle transients just fine.

This business about not being able to locate a subwoofer is simply untrue in my experience.

Perhaps it is based on experiments with pure sine waves. With the possible exception of a flute, musical instruments don't produce pure sine waves. A drum is often cited as an instrument that energizes a subwoofer, but a drum also produces percussive sounds at much higher frequency. These sounds should eminate from the same location as the deep thump.

Of course, you don't need to decide on a SW location until you get one, and when that happens you can try out various locations and decide for yourself.

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.

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.