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Just got a Little Phatty (woo-hoo, btw), and I expected the legendary MOOG 24db 4-pole LP filter to be the one I would use, but find that the 1-pole seems to cut cleaner through the sound. My analogue 101 is escaping me right now, and google isn't any help. Anyone able to post a primer on poles?

Please no 'do what sounds good'...I plan to, but am also the curious type.

pushre wrote:Just got a Little Phatty (woo-hoo, btw), and I expected the legendary MOOG 24db 4-pole LP filter to be the one I would use, but find that the 1-pole seems to cut cleaner through the sound. My analogue 101 is escaping me right now, and google isn't any help. Anyone able to post a primer on poles?

Please no 'do what sounds good'...I plan to, but am also the curious type.

Basically every pole cuts the volume by 6 decibels for every octave you move away from the cutoff point, its a slope. So a 4 pole Low pass filter cuts 24 dbs from each frequency octave above the cutoff and sounds "darker" or fatter than a 1 pole LPF which will sound brighter because it leaves more of the frequencies above the cutoff through.

The more poles the more effective or precise the filter. Soundsystem crossovers would use filters with 4-8 poles (I'm guessing) to ensure the subs are just getting subs for example.

With synths what number of poles to use is just down to taste.

Your 1 pole filter cuts through the mix probably because it's got more high end coming through (if its a LPF).

Just FYI, on most (decent) crossovers you can select the roll-off with a knob or whatever.

Ahhhh, yes..thanks so much.