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The distance between the human ears is half a wavelength of a sound having a frequency of 700Hz. At frequencies appreciably below this, the head offers no obstacle to sound waves, and so the amplitude of sound reaching the two ears is virtually identical11, 17-19.

Does anybody NOT spatialize lower frequencies? Seems kind of strange.

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You mean to tell me that you think it's not possible to localize a saxophone or a trumpet? How about a flute? 700Hz is right around F5 on the musical scale; near the upper registers of the former two, and right in the middle of the latter.

There is far more that goes into acoustic localization than merely wavelength. One of the biggest factors is timing, which the human ear is extremely sensitive to. Let's not forget how reflections and reverberation contribute to that element of auditory perception. The body is also extremely sensitive to pressure acting upon it, and acoustic sound is nothing more than cycles of pressure changes around us. Let's not forget harmonics, because pure tones don't exist oustide of an electrical/digital environment...including after they go through transduction to be turned into acoustic waves.

While it's true that localization becomes more difficult as the frequency of a sound is lowered, you need to get WAY down there for there to be an appreciable effect. Maybe this would be true in an anechoic chamber, but this question is a little too narrow minded in it's consideration.

I don't mean to sound condescending in this response, but, practically speaking...without supplying a specific context...this is a silly idea.

yes, i edited that last line...stupid omission on my part.

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Perhaps you guys should brush up your physics (after wiping the egg from your faces and apologising to the OP) and have a look at Lord Rayleigh's papers on sound localisation (over 100 years old and still worth reading.) What with the Nobel Prize and the professorship at Cambridge I think he knew what he was talking about.

If you're interested in the subject then look up more recent material by Michael Gerzon and Dave Griesinger - easily discoverable on the web.

Better yet, take a look at something like "Stereoplacer" - a VST which can do frequency dependent panning. Draw your own conclusions........

  • Gerzon and Strutt (Rayleig) both talk about mechanisms that allow for localization below 700Hz, specifically inter-aural time differences. Does our ability to localize decrease through certain mechanisms under 700Hz? Certainly, but there are mechanisms that lose their efficiency above 1500Hz as well...and 5kHz too. There's also a marked effect based on the number of channels in a playback system. I just think that it's irresponsible to make a blanket statement that it's pointless to pan when frequencies are below 700Hz. Context needs to be attached to that statement. – Shaun Farley Oct 29 '11 at 20:34
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I think it's generally accepted that frequencies sub ~80Hz are difficult to localise, hence the need for only one subwoofer in a consumer 5.1 setup. As Shaun states above though, there's a lot of clever stuff that the human ear / brain does to localise audio, so I think it'd be strange not to pan low frequency material.

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Shaun's answer looks pretty good, but just to pick on you a bit more: I don't understand your reasoning about the size of someone's head vs the wavelength of sound-waves.

I expect it's related to misunderstanding the nature of sound-waves as being something that looks like a sine wave, instead of being a series of pulses?

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The common wisdom is that we can't localize. However, while I may not be able to hear directionality in low frequencies, I am able to sense directionality from subwoofers. As a result, the classic offset single-sub design is uncomfortable to me. Following Bob Hodas' thought process described HERE (last sub-heading on the page), I've dual-subwoofed my home system with a subwoofer on each side, in line with the stereo mains. With the single offset config, what I sense is differential pressure on the tympanies, much like you feel when you've only got one window open in the car, the one next to you, and drive at speed, turning the interior of the car into a VLF whistle. You can feel that on one side as well. It's also a little like when you have a cold and one Eustachian tube is clogged. It kind of turns the head into a dual pressure-gradient receiver rather than a binaural receptor. ;)

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BTW you may be interested in another VST by the makers of Stereoplacer which does EXACTLY this - i.e. monos the low end of a mix

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Everything below 700Hz should appear in front of us in stereo? That's not how my ears work. I think that would sound very strange and would make mixing extremely cumbersome.

In music mastering I often widen the highs and narrow the lows (below about 80Hz) using Ozone 4.

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It doesn't have to appear in stereo and probably shouldn't. In fact, my point was that when placed to one side, low frequencies are uncomfortable to me. You can experience this with some early stereo pop albums where the engineers really had no idea what to do with the sound field so they panned the bass to one side and the guitar to the other. Yuk.

However, there is at least one mastering format where panned bass is a problem and that is vinyl. Conflicting panned bass sources can cause some really wonky issues with, for instance dual drummers and outboard kick drums In fact, loud, out of phase bass in the two grooves will neatly eject the needle!

Bob

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