Thanks for the information on attenuation Walt.
A couple weeks ago, I was attempting to record the ocean at a
place called Devil's Cauldron, and even with my recording levels
down around 3, I still ended up with clipping. Now I'm thinking I
might get better results trying it again with the -20dB mic
attenuation switch on my PMD-670 switched on.
Also, you mentioned:
> 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.
Does the 5-7 best performance range apply specifically to the
Portadisc ? If so, do you know of an easy way to determine the
best performance range for other recorders?
-John Hartog
--- In Walter Knapp
<> wrote:
> 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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