From: "jessehammons" <>
> My question: what are the disadvantages of filtering out unwanted bass
> frequencies in post-production? (err, post field recording) I would
> prefer to do this in post, because if I filter them out, I won't be
> able to play them on my friend's Udder Thump 2000:
> http://ontology.com/canton/projects/udderthump2000/index.html
>
> Now wouldn't that be a shame?
>
> Seriously, do low frequency sounds somehow introduce noise or other
> problems into the recording chain?
The only problem, and it's a weak argument, is that you might overload
the pre and clip. This sort of problem is from a misunderstanding of
digital recording. In analog recording you had a limited dynamic range
available and it was very important to use all you had. In digital you
have a dynamic range that's much greater than most environments you will
record, so you can allow the headroom for that bass and still get all
the high frequencies.
Note that consumer gear pre's can be more of a problem as they generally
overload a lot easier. Only experiment will tell you if it's a problem.
I hear far more recordings that are obviously missing the low end. So, I
don't set rolloff in the field and handle it in post as a general rule.
Mics don't record extra of the low frequencies, just what got to them.
As long as enough headroom was allowed I see no difference between using
a mic's rolloff and doing it in post. Except that the mic is a preset at
a specific frequency, and in post you can set that rolloff to the exact
frequency you need. That's rarely the one the mic uses. Post filtering a
recording that's got mic rolloff can make it a little harder you can't
undo that filter.
It's a very crude way to deal with man made noise. Careful filtering in
post will do better. Only set the rolloff when you have a specific need
that it takes care of, don't get in the habit of setting it and
forgetting it. And, even in post don't automatically remove that low end.
I'm of the opinion that a lot of mics do a poor job on the low end, but
that's a separate issue. A good mic should at least handle the low end
without creating problems.
Walt
________________________________________________________________________
________________________________________________________________________
|