We always put a -30dB reference tone at the head of every recording
followed by signal that is recorded at a known pre-set input level
setting. That way, if we do decide to normalize, we can always go back
to the reference tone and reset the track to a -30 setting. Then the
track can always be re-calibrated should that be needed.
This works only as long as both the reference tone and the recorded
signal remain part of the same contiguous clip and haven't been fussed
with separately.
Bernie
On Jan 18, 2012, at 12:22 PM, Curt Olson wrote:
> Robin Parmar has already given helpful replies to your questions,
> Pete, but I'll add a few thoughts of my own...
>
>> I've started to accumulate a bit of a collection of recordings, and
>> I have a few basic questions about processing them ready for others
>> to listen to.
>>
>> 1. How do I decide how much to increase the volume by? It seems to
>> me that normalising to a particular level will have haphazard
>> results because it all depends on the loudest sound in the
>> recording. Should I pick a typical piece and adjust till its peaks
>> are at some particular level? If so, what level? Or should I be
>> listening to some sort of reference track and doing it by ear? What
>> I'd like to avoid is the listener having to dive for the volume
>> control because it's too loud or soft.
>
> Good instincts about normalizing, Peter. It is rarely ever good
> idea, IMO. That said, I almost always boost my nature tracks in
> steps with a combination of compressor and level-maximizing peak
> limiter. Not always to full scale, however. Exactly how much is a
> matter of artistic judgment.
>
> For individual tracks, I tend to think in terms of the loudest peak
> event in the track, and decide how loud it should be based on where
> it sits in the overall spectrum of quiet to loud events in real
> life. I might allow a Blue Jay calling from ten feet above the
> microphone to peak at -.3dbfs (db relative to full scale), where the
> same bird calling from across a small lake might not even hit -30
> dbfs. It might well be appropriate for a beaver splashing its tail
> 30 feet away from a microphone on the water's edge to peak at -.
> 3dbfs, where the same event 100 yards across the beaver pond might
> want to hit only -18dbfs. It's all relative, and it's all up to you.
>
>> 2. If the above will result in clipping of the loudest parts, what
>> should I do about them? Audacity has a Compress function which
>> looks like it might help bring them down a little without affecting
>> the quieter parts. Is there a better way? (An example of the
>> problem would be where for a few seconds a bird sings just a couple
>> of metres from the microphone.)
>
> I use ProTools for all my editing, so I can't speak with much
> authority about Audacity. But in general, I like using a small
> amount of compression (2-3 db) on loud events and also a small
> amount of peak limiting (another 2-3 db) on the loudest events. But
> keep in mind that some soundscape recordings don't contain
> individual events loud enough to qualify. Again, it's all relative.
> And a lot of this comes only by experience, which means potentially
> a lot of trial and error before you've figured it out for yourself.
>
>> 3. Is there a standard length for fade in times? I randomly picked
>> about 10 seconds for one, then discovered that too long a fade in
>> tricks the listener into turning up the volume, only to discover in
>> a few seconds that it has to be turned down again.
>
> There is no standard fade length, as far as I'm concerned. Some
> material seems to want shorter fades, other material seems to want
> longer fades. I'd suggest maybe starting with 10 - 12 seconds and
> adjust form there as needed. I agree with Robin that linear fades
> are usually less interesting than logarithmic fade curves.
>
>> 4. I've noticed that the default vertical scale in Audacity runs
>> from -1 to +1 (linear?) whereas in Sound Forge it's in dB. Is there
>> any reason to pick one or the other?
>
> Can't help with that one. Sorry.
>
> Curt Olson
> http://minnesotasoundscapes.com
>
> ------------------------------------
>
> "While a picture is worth a thousand words, a
> sound is worth a thousand pictures." R. Murray Schafer via Bernie
> Krause.
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