[sdiy] Understanding Q in filters

[Dan Snazelle]

So i have been trying to find and or (modify) a low pass filter with variable Q that only uses one or 2 opamps (at most a TL074).
I have tons of books that get into filters but most of them are NOT aimed at using them for music.

Don Lancasters book is excellent but one problem i have with almost all of them is figuring out WHERE in the schematic to add a pot to control the level of Q (or damping). often Q is mentioned, but is described as being changed with capacitor choice, NOT resistor value, which would obviously make it hard to control with a pot.

SVF desings seem to be a bit too complex for what i am making right now, which is something with ideally very low parts count.

heck even a link to a datasheet that explains changing Q would be great


filters seem to be an area that a man could spend his life on.....

thanks

and happy holidays




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