From: "geoffjcarey" <>
>
> Can anybody help in understanding the attenuation function on my
> Portadisc. How does it work, what does it do and what is the optimum
> setting? I can hear how it works through my headphones, of course,
> but I'm not entirely sure whether I should be going for more or less
> attenuation.
This cuts the signal coming in the XLR inputs, by the amount specified.
I'm not sure, but I believe it does this before the preamp right at the
input end. There is no optimum setting, it depends on what you are
recording, what mic, or if you are using a pre. Most times you want to
set 0 attenuation. What you hear through the headphones is pretty much
what you get. Depending, of course on your headphone gain setting, and
the quality of your headphones. Note that the Portadisc's line setting
is probably just -45 dB attenuation fed into the pre. Bothers some folks
but not a problem to me. The Portadisc's pre is very good.
My rule is not to use it unless the gain setting I end up with on the
Portadisc is lower than 3-4 to obtain the headroom I want to see on the
meter. Then attenuation will get your preamp gain back up in it's best
performance area. 5-7 is it's best performance area.
On the same thought you will not get as good a recording if you have the
gain way up at the top end. Get closer, or, maybe, use a pre to get a
little more gain. Of course the pre also amplifies the mic self noise,
so you can't go very far that way.
Main place where I use attenuation is working with the Sound Devices MP2
pre. There I want both the MP2 and the Portadisc to be operating in the
sweet spot of their gain adjustments. For a lot of the time that results
in needing attenuation between the two. That's the way I get max gain
from the Sennheiser MKH mics. Noisier mics would not be worth it. Note
to get the attenuation correct I use a XLR link that provides 15dB
attenuation to start with. Sound Devices used to sell the link, but I
made my own. Then adjust the Portadisc, usually another 15dB attenuation
on it.
Walt
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