frequency multiplier (x10) in EQ - how is it done?

[Family Hoof]

Forgive me if the answer is obvious, but I have not seen any schematics of comercial units with this 'freq times 10' feature and cannot imagine how it's done. My knowlege of EQ circuitry is limited to passive RLC. Must frequency multiplication be active? DSP? How do A*val*on or Mill*enn*ia Media accomplish this in their products? And while we're on the topic, would it be possible to have a 'frequency divide by 10' function on an equalizer instead?

Thanks for enlightening an EQ newbie! :thumb:

 

[PRR]

> (x10) in EQ - how is it done?

Switch in a cap 1/10th the size.

 

[Family Hoof]

[quote author="PRR"]> (x10) in EQ - how is it done?

Switch in a cap 1/10th the size.[/quote]
Well duh! I thought for sure it was something more clever than that!

Thanks, PRR

 

[bcarso]

In general, for a two-pole active filter the Cs both change by the same ratio, or the resistors that determine frequency change by the reciprocal ratio. Or, you can split up the duties among the Rs and Cs. If the fine freq adjustment is made with a dual pot, then changing the Cs alone is usually the easiest.