In the recent discussion about digital recording a lot of attention
was spend towards normalizing. I just want to say somethings about it.
I guess most of us know what it is; the loudest peak of a selected
part of sound is found, the total selection is then boosted, or cut
so that this one peak has a new value.
Most of the time normalizing is meant to boost the peak level to a
value close to the digital max : zero dBFS.
This is a operation most often done right before publication of the
sounds (either on CD or as a MP3).
When editing wav files I always first run statistics on the file, I
first remove DC offset (if it is there at all).
After all kinds of trimming, fades and filtering I save the file and
if it is a single file not meant to be a part of a group of files, I
just normalize it to -0.25 dBFS.
If it is part of a series of files, I will set the RMS volume of the
file relative to the other files.
I think that most editing software don't do normalizing before and
after edits. What they do is when you mix / past or add stuff you get
a popup window asking you what the volume of the edit is; this is not
normalizing, this is simply a user choice in how loud the added
signal is in relation to the already existing signal.
If I mix 2 signals, and put both at 100%, then both signals are
equally loud. This does not mean that both signals are normalized
towards 100%, it just means they were neither cut nor boosted, they
were mixed together with unity gain.
So in this case the percentage is a volume change instead of a
normalize function.
In general, while editing files I prefer to do volume changes of -10,
+10 or 20dB; this case it is far easier to go back to the original
sound level then in the case of normalizing. After all, when you do
normalize; do you have any idea whether the signal was cut or
boosted? You probably will, because you can hear it is louder then
before, but HOW much louder? Do you know exactly how many dB's?
If the answer is no, you are no longer in control.
That is why - when I am in the editing stage - I rather do discrete
volume changes then normalizing.
Regards, Evert
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