1. Microphones don't hear any more than amps are emotional. You answered your own question when you mentioned the frequency deviations in various angles of their polar patterns. People have frequency deviations when objects are not equidistant from both ears. STop thinking in Mono Tim unless you've got only one ear and it's on your forehead.
Ha! Quite the comic.
So Jack, please explain how microphones are NOT mono? One microphone is a recorder of ONE POINT. Mono. There is no consideration of height or width -- all sound arrives at the microphone at one point, and that is the mics perspective. Polar patterns have absolutely nothing to do with it.
Two microphones spaced apart are two mono recording sources that record what is presented to them at their location. There is no sense of direction. It's all summed at each microphones point placement.
When those two points are played back to speakers, and assuming the mics are horizontal to each other, the L & R channels reproduce exactly what each mic heard at its single reference point, respectively. The sum and difference of signals received in that space, when presented on two channels, gives the spatial characteristics we call a sound stage. Its point of reference can be only the two mono points received by the mics, one recording channel each. The sum and differences of the waveforms in time presented at each mic can only be significant to the plane they are in relative to each other.
That means that the only thing that can be preserved in two mics placed horizontally, is the horizontal space between the mics. Nothing vertical, since all information from any direction is summed by each mic individually to mono. Do you get that?
If the mics were spaced vertically, but your speakers were horizontal like normal, your 'soundstage' L to R would be equivalent to the vertical information received by the mics (top to bottom) and would sound pretty odd because there would be no real lateral information from the mics. Of course, if your speakers were placed as the mics were, above one another, then there would be real height information, but nothing horizontal.
If you can tell me how a mono point source receiver such as a microphone can record all positions around it uniquely into one channel, and then be presented with another mono point source next to it horizontally, and magically produce vertical (and presumably 360 degree) positional detail, I'd certainly love to hear it. Show me in science and math, not anecdotal accounts.
And in the studio, there is no mixing or modifying convention for vertical height of a horizontal pair of microphones on two channels. You can play with phase and stretching the distance between the microphones (by subtracting mathematically the L-R signal from the L+R signal), or reducing the distance by summing the L & R channels, but that's it. You can play with Doppler effects, comb filters and fine time delays to produce some unusual effects between the speakers but they have no bearing to reality, just as an effect.
Oh, I received my Chesky test record and evaluated the LEDR test. I DO hear movement vertically above the speaker in that particular test. As the image rises I also hear considerable out of phase 'pressure' between channels and between LF and HF transducers. Looking at spectrum and phase analysis of the sound they are using to produce that movement, it's a combination of balance between channels and balance between HF and LF drivers and some sharp notch filtering and a certain amount of time shifting one channel from the other going on to produce that effect. It is limited to the particular type of 'grating' sound they used to produce it, and those operations create the effect of synthesized vertical movement. But, with out of phase audio content as a side effect of it.
So my speakers and system are perfectly capable of producing the LEDR effect, yet there is absolutely no height information other than distance between drivers when playing well recorded music (or even not well recorded music).
I don't doubt that some folks have heard the height artifacts in music, only that however it was perceived, it had nothing to do with the original recording and instrument/mic placement.
If someone could volunteer some particular recorded tracks where this effect appears to be repeatable, (preferably in jazz recordings) I'd like to see what happens on playback here.
--Bill
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