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Re: Question re MP 3 compression; Kherz; and Digital Recording Basic

Subject: Re: Question re MP 3 compression; Kherz; and Digital Recording Basic
From: "John Lundsten" lundsten_john
Date: Tue Apr 3, 2007 3:41 pm ((PDT))
> Lou Judson wrote:
>
>> 3. As far as I know you can only make MP3s from 16 bit audio.

I use Adobe Audition for this job, which can produce Mp3's from any format.=

I tend to be going from 32bit float or poss 24 Integer and sometimes 16 bit=
.
I've not done critical listenening comparisons recently (about 5 years ago=

actually) but comparing the LAME encoder to Fraunhofer one in Cool Edit Pro=

V1.2  (an earlier version of Audition) the Fraunhofer one was the clear
winner also at the time LAME didn't do variable bit rate encoding which can=

be VERY useful IMO.

>> dither 24 to 16 and save as a new files before compression.

Yes this is the conventional wisdom but IMO an oversimplification:-
Dither is great, makes digital audio linier rather than steppy, a possible=

issue is it does this by adding a small amount of noise - typically noise
will be added at about -95dB on a 16 bit dither.
Almost all recordings will have courtesy of Ambient noise, mic & mic amp
noise rather greater than that anyway so:--
In practice most "nature" recordings will self dither without any extra
help.
So IMO in these cases only dither if:--
1) in post production you fade to zero or otherwise create sound files with=

sound levels below about 90dB below max level.
2) you are recording very loud stuff

On the other hand the ambient/mic/amp noise will likely be so much louder
than the dither signal that whilst it may do no good the harm is very
minimal - but hey if it's not needed why add it?

To paraphrase others comments good advice
Use highest quality for the original record [you will need headroom and you=

may need to drag some very quiet stuff up in level]
This can be very successfully squeezed into a lesser format for listening
enjoyment
John L






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