Rob Danielson wrote:
> I can predict that the
> trim knob setting will be closer to the clockwise (-50dBU) end of the
> range.
Yep.
> But, as to finding the trim setting "sweet spot," for this
> mic, the calibration procedure isn't quite clear to me working from
> Marc's directions or the Fostex's manual. Can someone describe this
> procedure again and perhaps some of the principle(s) involved?
Try this: make a 64dBA diffuse sound field with 200-2KHz band filtered
pink noise on monitor speakers. Put your mics at the measuring point.
Set the record level to 2:00. Set the trims so that meters read -6dBFS.
If you can't get that level with the trims at max, try 3:00 as your
record level setting.
Mark the positions of the trims and record level. That setting would
be a good starting point for most soundscapes. You've got extra gain
by turning up the main knob, and vice versa. Bonus is you can
determine the SPL of what you're recording.
> Once determined, is this trim knob position essentially,"unity" or
> _the_ optimal setting for the particular mic no matter the sound
> levels encountered (as I believe Marc was alluding to)? Rob D.
I'd say you'd be good in most situations with those particular mics.
If it's so loud that you have to turn down below 10:00 or so, you'll
probably have to lower the trims to avoid preamp clipping. Experiment
with the machine in louder sound fields to find out just where that
danger point is.
-Dan Dugan
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