Re: Normalize samples?
Re: Normalize samples?
- Subject: Re: Normalize samples?
- From: Tim Omernick <email@hidden>
- Date: Tue, 16 Nov 2004 22:26:05 -0800
I've been getting a lot of off-list replies which state that predicting
a microphone's input level is practically impossible. I have an
alternate solution to my problem, which I will share for the benefit of
everyone on the list who might be attempting the same sort of thing.
Instead of hard-coding a "minimum volume" threshold, I measure the
average volume of the ambient noise coming through the microphone over
a period of a few seconds. From that average volume, I can then derive
a gain value such that when the gain is applied, the signal is at or
near zero. Then, I allow any samples with a volume greater than zero
to be further processed.
It's sort of like calibrating a scale. :-)
Thanks,
-Tim Omernick
Engineer, The Omni Group
On Nov 16, 2004, at 6:15 PM, Tim Omernick wrote:
Hi,
I searched through the list archives and could not find an answer to
this seemingly simple question. The application I'm working on needs
to perform some processing on samples from a microphone, but only if
the volume level of those samples exceeds some threshold.
Is there a way to normalize the samples passed to my IOProc so that
that every amplitude value lies within the range {-1.0, 1.0}? I get
different amplitude ranges for different microphones, even with
identical volume settings.
Am I missing something?
Thanks,
-Tim Omernick
Engineer, The Omni Group
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