Would you mind explaining how the vumeterdsp.cc from jmeters works?
In particular how you arrive at the filter-constant:
_w = 11.1f / fsamp;
With the DSP using a 2nd order low-pass filter, and since VU should have
an integration-time of 300ms, I'd have though it should rather be:
_w = (1.0 - exp(-2.0 * M_PI / 0.3 / fsamp)) / 2.0;
for large values this can be approximated by _w = 10.468 / fsamp;
What am I missing?
I suppose the gain is arbitrary, seeing as it is mapped to a GUI element
without any numeric display, anyway. But is there something special about:
_g = 1.5f * 1.571f;
1.5 * M_PI/2 ?? ie 90 degree deflection? But why the 1.5?
The context of all this is re-using your code to implement a VU meter in
Ardour3. For reference, the source-code is at
Some experienced beta-testers contested the ballistics of the meter and
I'm trying to get to the bottom of it...
Since this might be of general interest, I'm CCing LAD.
thanks in advance,
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