Sounds like the MSGEQ7 will be the way to go then (saves me a lot of coding hassle too). I'm pretty new to visual effects; I definitely want to do some frequency-related effects (spectrum analyzer, etc), but would loudness effects be possible through the MSGEQ7? I would think I can get absolute loudness by taking all of my frequency readings from the MSGEQ7 and summing them to get an overall loudness, correct?
tmd3:
This gizmo claims that it can operate as a limiter, and accommodate 60 dB on its inputs with only about 0.5 dB change on the outputs.http://www.onsemi.com//pub/Collateral/SA575-D.PDF
It's available in a through-hole mount for something around $5.50 from Mouser, though the through-hole version is marked "end-of-life." If that's true, you should be able to get the a flat output response over a voltage input range of 1000. Using the "+10 dB ~ twice as loud" rule of thumb, that's an apparent loudness range factor of 64. That might do it.
This looks promising. I was reading elsewhere about automatic gain control amplifiers, I assume this IC's advertised automatic level control is the same thing?
I'm not sure I understand "...voltage input range of 1000." Do you mean over a range of 1000dB, 1000V, 1000x, or what? I'd like to get the signal down to 0.5V peak to peak for optimal input to the MSGEQ7. Assuming a max range of ±17V (V = sqrt[50W * 6 ohms], overcompensating the internal resistance of the speakers a little), I should then be able to use this as input to the IC. The data sheet suggests that the output deviation for ALC mode is ±0.2dB about the nominal 0dB, which is about ±1V? If this is correct, then I should be able to do a simple voltage divider at the output to halve the output and have a safe input to the MSGEQ7.
I have drawn a schematic based on the diagram in the data sheet and attached. Does it look correct?
Thanks,
Shepard
