From: Dan Dugan <>
>
> Rich Peet wrote,
>
>
>> > 1. When there is no audio that is important above 15,000 cycles I
>>
>>> drop the gain in this region by 50% to 75% (6db to 10db) on a slope.
>>> It does not effect the overall recording and hides the ragged
>>> compression of this area that can be seen on a spectral display which
>>> is the signature to many that the recording was a MD. It really does
>>> not change the heard audio any, but for those that pay attention it
>>> fools a few of them into thinking they may be looking at a 24 bit
>>> recording with >100db s/n. I use it with restraint but hey if it
>>> makes someone think that I am better and have higher tech equipment
>>> then I do then it was worth the effort. This part of the edit is
>>> vanity.
>
>
> And Walt commented:
>
>
>>Unless they use sonograms, few would find the MD effect you speak of.
>>Nor is it consistently there. If it is in your equipment, then there may
>>be some other fault with the equipment. It is certainly not consistently
>>there in all the sonograms I've done on MD recordings.
>
>
> I monitor my work with Spectrafoo instruments, and the effect that
> Rich mentions is quite apparent in spectrum analyzer displays of
> perceptual coded stuff. It doesn't show on sonagrams. It's a
> sure-fire indicator that you're listening to a perceptually-coded
> recording, even though you usually can't hear anything strange. I'm
> going to play with the rolloffs as Rich suggests, but there isn't any
> audible need for it--as he says, he does it just to clean up the
> appearance on an analyzer.
One could hardly call such equipment common. Pretty rare person who will
have access to such.
If you could hear the perceptual coded stuff, that is a failure. A good
coder will do the work and not be heard. I don't think they ever claimed
to do nothing, only to not be heard.
I suppose it depends on your sonogram software. I do see the effect of
coding in the high frequency end of some MD recordings. Mostly if there
is something of fairly high intensity in that area. You do have to have
sonograms that are fairly well resolved, and have to understand what the
sonogram software itself puts in there.
I would be more interested in what specifically you are seeing in your
spectrum analyzer. I've got some spectrum analysis software, but it does
not appear to give me as good a look as a good sonogram.
I note in my reading of Ken Pohlmann's book that he's gone to triple
blind listening tests, preferably with trained listeners. He's pretty
down on hardware type tests, saying they miss the point. He also notes
it's getting harder and harder, and that the unencoded sample does not
necessarily come out on top in that work. They are doing the tests to
improve encoders and evaluate one against another. They realize we will
be working with such things.
He also has some ideas in how perceptual encoding can make systems
better than without the encoding.
> Because I work in theater, I often have to do noise removal
> processing, and I keep buying expensive software that does that. Even
> the best is problematic, and I rarely do more than plain vanilla
> equalization/filtering to my nature recordings. I would only use
> dynamic noise filters on nature sounds if I was composing, mixing
> cleaned-up specific sounds over a natural bed.
>
> -Dan Dugan
I mostly don't filter either, the scientists I deal with could care less
as long as they can make out the calls. I did use considerable filtering
in the ID clips for the CD. Particularly in some cases where our choice
of material was very limited. There you are not really trying to
preserve the other sounds. You are trying to get the call isolated so
people can learn it.
If I use a dynamic noise filter, it's the last thing in line. After all
other cleanup is done. Even there it can only be used lightly. Very
annoying filter to use.
I cannot afford to continue to buy different software, though SparkXL is
a pretty expensive package in my thinking. Got lucky and got it off
ebay. So only have to keep it upgraded. Having the support to experiment
with expensive software would be nice.
Walt
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