Question on Perceived LF

[wkhanna]

At what point does low/lower frequency become directional?
IOW, at what frequency can you begin to recognize the location of a LF sound/source?

[mazurek]

I'll tell you the complication before other people tell you the answer. Crossover slope, high frequency breakups, and higher order distortion prevent a uniform guideline.

I'd say the best answer is to put infinite subwoofers everywhere.

[jdybnis]

The answer I like best is the point where 1/4 the wavelength is shorter than the distance between your ears, or about 300Hz.

[littlesaint]

Below 1KHz, wavelengths are large enough to diffuse around the head, so there is no perceived difference in pressure levels between the two ears. Your head is no longer in the way. At this point, phase difference is used to localize sound. The sound wave would arrive at each ear at different times and slightly out of phase. The point at which the sound becomes non-localized is the wavelength at which the brain can no longer perceive a difference in phase.

[wkhanna]

I'd say the best answer is to put infinite subwoofers everywhere.

OK. So all I need is thirteen subs.

Then let me rephrase my question.

Has anyone installed a sub, and then sat down to listen to … say……some acoustical jazz, only to discover to their utter disappointment, that the sound of the stand-up bass was coming from the location where the sub was located, or worse yet, floating between the appropriate position within the sound stage that was produced when simply using the original 2.0 configuration and the current location of the sub, depending on the frequency?

[Bent]

Yes.
My As-15 clone was fabulous at y old house withjout much tweaking at all
It is moderately less so at my new house. I'm quite sure it's placement related though.

[Kevin Haskins]

There isn't a good answer for this. The answer is "it depends".

Some subs have a fair amount of output above the low pass filter. The filters used in typical plate amps are SUPPOSED to be 12db/Oct up to sometimes 24db/oct variable low-pass filters. They don't always work as designed. For one, sometimes the sub has a rising or falling acoustical response and you get other the a true LP behavior out of the combination. Also... the simple pots in a opamp filter circuit often interact with the other parts of the circuit. You change gain AND the LP function when you change one or the other. They also rarely have anything like the true displayed electrical transfer function.

Second factor... you get harmonics of the bass signal in the cone output even though its filtered. Depending on the levels of those harmonics, they may be audible and since they are above the theoretic LP filter they give directional cues.

If subs worked as they should (the analog single processing section) and the driver is low distortion, then you should be relatively unable to locate it under say 50-60Hz. You would still be best off positioning between the front two speakers though if you want to be 100% confident in not getting localization cues.