Re: [LAU] Focusrite Scarlett 18i8

On Wed, Jan 08, 2014 at 05:04:38PM +0100, Robin Gareus wrote:

> On 01/08/2014 04:43 PM, Fons Adriaensen wrote:
> > On Wed, Jan 08, 2014 at 03:51:41PM +0100, Robin Gareus wrote:
> >
> >> I had calibrated -18dBFS on all of them to the same source (a 1KHz sine,
> >> which I believe to be 0 dBu). That's how I found out about the rubber
> >> controls effect in the first place.
> >
> > O dBu ? So you measured the line inputs, not the mics ?
>
> I don't think I did. I used an unbalanced jack (out from a 4th
> soundcard) -> balanced XLR (pin 2,3) to calibrate.
>
> Then a XLR plug with a resistor between pin 2,3 for the noise measurement.

I just checked the calibration data for mu UA-5, which as far
as the analog part is concerned, is similar to the UA-25 (apart
from having separate line inputs which do not pass via the mic
preamps).

At max gain, the required input level for 0 dB digital is around
-42 dBu, fairly normal for a mic input. To produce -18 dB digital
with 0 dBu input you'd need 60 dB less gain. Maybe that's possible
with the gain pots just above the minimum, but anything measured
with that setting wouldn't be very representative.

Ciao,

-- 
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
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