rs
Could it be that what you're hearing is the nyquist freq. foldover
from sounds in excess of 22kHz? I know that digital recorders employ
brickwall filters at around 20k, but maybe they're less than perfect
and the amplitude is in excess of the filter's capabilities? Hence
you would hear artifacts resulting from the difference of the
original frequency minus 1/2 the sampling freq. e.g., 24kHz-22050Hz
=3D 3500Hz. Add that to your original signal and you'd end up with some
interesting inter-modulation distortion.
I seem to remember experiencing this while recording an analog
synthesizer a few years back.
Paul
>Rob Danielson wrote:
>> Hello--
>> I don't believe its over mod. It can happen with one critter on both
>> DAT and MD and is of course more evident with multiple singers.
>> Marty, any chance those saturated, hi, Hz's could cause some sort of
>> phasing distortion? Veljo, I assume you're not getting this
>> distortion, what medium do you record onto? Thanks! Rob D.
>
>Is this a case of seeing multiple reflection paths from the environment?
>The higher the frequency, the more such effects would be evident.
>
>I once recorded some gray treefrogs that had located holes in a loose
>stone wall above a pool. They had obviously chosen the holes as natural
>megaphones. But there was a lot of odd phase effects there with all the
>possible paths, and they are not that high a frequency.
>
>The other part could be that at high frequencies the waveform is a very
>jagged sample. There could be interactions there as well. Which would be
>artifact.
>
>Digital over mod is fairly easy to find by sonogram as it spatters
>banding all over the frequency scale. Looks kind of like harmonics, but
>too close together and both up and down from the actual.
>
>Walt
>
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--
Paul Dickinson
Film/Video Teaching Associate
UIC School of Art and Design
Ph. 312-996-0767
Fax 312-413-2333
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