> David, I am using a microphone pream with two channel in the mytec 196 =
adc conveter wich have AES/32 digital output and I would like to have four =
channels.
> The nagra seven has AES/32 digital input I could mix the two channels in=
the nagra with the two channels from the AES stereo digital output from th=
e Mytek.
> In the field I could record with parabola and with two mics in stereo m=
s, blumlein etc.. And I could monitor in the field the mix in the Nagra.
Jos=C3=A9,
Yes, I guess, but you can't adjust the mix later as you could with a four
track recorder. Before anyone asks: Could you use two stereo recorders
running together?
If they are completely different sounds, you could do this. The problem is=
if you mix two recordings of the same sound source with a time difference.=
Even a tiny time difference could be audible.
The Nagra has a time code function accurate to better than one video frame=
or 33 milliseconds, but that is not nearly accurate enough when mixing
shared sounds. There are two possible problems, flanging and a shifting
stereo effect.
The time difference when mixing two tracks from the same sound source which=
have a 1 ms difference will give a peaks at 1KHz, 3KHz, 5Khz, and so on, an=
d
troughs at even frequencies, producing "flanging" or a "comb effect filter"=
.
1 ms corresponds to only 44 samples at low resolution.
The other effect would be a stereo shift produced by a time difference. My=
ears detect a shift of 1 degree per sample, or roughly 30 degrees per 30
samples. These are the time differences used by blumlein and SASS rigs and=
other mics spaced at a nominal 170 mm - the width of a head. That's 22
samples max and still in the same ball park for numbers. You won't find
clean mixing possible with two different digital recorders.
Now someone write in and say that they have done this successfully. :-) I
would reply "always experiment", but not if it is going to cost money.
David Brinicombe
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