Posted by: "Raimund Specht"
> I agree that a stereo recording is probably always more pleasant for
> listening than a mono recording. However, if you are interested in the
> scientific analysis of the recorded sounds, I would always prefer mono
> over stereo.
>
> It is true that certain stereo recordings (employing the M/S
> technique) can be converted without any loss of quality into mono.
> Unfortunately, the additionally required figure-8 microphone would
> make the recording system more complicated, which often cannot be
> justified.
>
> However, other common stereo techniques such as XY, AB, ORTF or any of
> the head-based or baffled set-ups can introduce unwanted artifacts.
> Among the potential problems are comb filter effects or simply the
> fact that none of the two microphones are pointing exactly at the
> sound source. Due to physical limitations, there is no microphone that
> exhibits a perfect omnidirectional pick-up pattern for all signal
> frequencies. At least at frequencies above 10 kHz, the frequency
> response is no longer flat for off-axis sounds, which means that high
> frequency components will NOT be recorded properly.
All of this assumes you are in a nice acoustically perfect test
facility. The effect of polar variation on the incoming sound is as
nothing compared to the effect of the environment around the sound
source. Record with mono and you have no clue about that, record in
stereo and you have at least a little chance to analize the complex
soundfield of natural situations.
The biologists I work with have no trouble at all doing scientific
analysis on calls recorded in stereo, nor do I. Sonograms, the primary
tool for birds and frogs are just as useful if not more useful done from
stereo recordings. I think I'll stick with the opinions of the
biologists, which is they strongly prefer stereo for their scientific
work if they can get it.
It's is not just a matter of more pleasant at all. It's a matter of
gaining a lot more information. Which can, of course, make analysis
more complex as there is more information to gain.
Walt
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