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Help me better understand Noise Gates
In article
(Scott Soderlund) writes:
Hi,
I recently started working on a project where the computer captures
samples of someones's speech. Each of these samples is run through a
noise gate to improve the quality of the sample. I've done a lot of
reading to figure out how noise gates work and have pretty much come
up with that they help to lower the perceived background noise. Is
this correct? In my case, I've got a checkbox that is checked to
start running the samples through the noise gate. There is also a
slider bar that adjusts the threshold from 0 to 100. The comments
I've found inside the program indicate that the "0 to 100" is supposed
to represent the percentage of total signal strength. Is this likely
correct? What does this mean? I understand that when I change the
threshold that everything above the threshold is supposed to get
louder, but how does this relate to the total signal strength (and the
threshold being somewhere in between 0 and 100)?
Thanks in advance for any advice!
Scott
A noise gate works by sensing the signal amplitude and comparing it with a
threshold value: if the signal exceeds the threshold, it is passed through; if
it drops below the threshold it is not passed. This has the effect of turning
off low-level sounds, like background noise, as long as they are quieter than
the threshold level. Signals above the threshold don't get louder (unless the
gate also adds gain), but signals softer get turned off.
There are many approaches to gating and some are more complicated in terms of
the time course of the signal switching on and off and the amount of
attenuation below the threshold, but they all do essentially the same thing.
-Jay
--
x------- Jay Kadis ------- x---- Jay's Attic Studio ----x
x Lecturer, Audio Engineer x Dexter Records x
x CCRMA, Stanford University x http://www.offbeats.com/ x
x-------- http://ccrma-www.stanford.edu/~jay/ ----------x
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