Output cap to control bass response?

[Blair]

Is there a good calculator to find the coupling cap cutoff frequencies for the bottom end?

I can use my scope and a meter, but it is trial and error. I have a guy that wants a preamp for his mids and highs, so I assume around 200hz or so?

Thanks!

Blair

[DeathRex]

This would be my best guess:

1/2πFC
2 X 3.14 X 100Hz X 0.00000001 (10nf) = 159kohms.
2 X 3.14 X 250Hz X 0.00000001 = 63.7Kohms.
2 X 3.14 X 250Hz X 0.0000000001 (100pf) = 6.37Mohms.

Alot of my German radios have a BASS switch, that bypasses a 200 to 500pf cap. The resistor after the cap is usually the volume pot of about 1.3Mohm. So you're basically making a resistor divider with the resistance through the cap increasing with lower frequencies.