Sunflowermanuk wrote:
Thanks Scott, sounds like a no-brainer solution then - I'm going
shopping for a clutch of inline attenuators to put between mic and pre.
For what it's worth, AKG used to make an attenuator for the C451 that
screwed between the capsule and body. Nowadays if you want one, you
have to pay about as much for it as a halfway decent preamp to some
greedy eBay seller. An outboard attenuator is fine, and there's no
appreciable difference between them. At least there shouldn't be - but
they used fixed resistors, and I doubt that any of them use better than
1% tolerance resistors. This could unbalance the input to the preamp
and reduce the common mode noise rejection, but if you're feeding a
huge signal voltage to the preamp, this isn't likely to be a concern.
But isn't it nice to have one more thing to worry about?
I believe Rich Chinn's web page
http://www.uneeda-audio.com has a
section about building your own pads. If you care, you could build your
own out of 0.1% tolerance resistors. We got into this discussion not
too long ago and one of the Google wizards found at least one
attenuator's spec sheet that actually mentioned the tolerance or
matching of the resistors. It's most likely Shure since they're the
kind of company that would care to put that sort of data on their
sheets.
As long as the preamp isn't clipping, you might want to use it to get
whatever sound it imparts to the mic (putting a pad between the mic and
the preamp will change the loading of the preamp on the mic, which may
change the sound), and put the attenuator between the preamp output and
A/D converter input. Note that "change" does not necessarily mean
"degrade" unless you consider that any change, good or bad, is
degration.
But most A/D converters have input level controls unless yours is one
of those boxes that hooks to a computer and doesn't have any controls.
If you have knobs, use them before putting anything else in the signal
path.