"Alex Polite" <notmyprivateemail@xxxxxxxxx> writes: > Are there any tools that will help me define the notch filter by > looking at the my audio? Jamin's actually quite good for doing this, since it's got a nice spectrum display and interactive EQ settings. Failing that, you could use a LADSPA filter (like "Single band parametric") and a spectrum analyser (like Jaaa) and just tweak the filter settings until the peak you see on the analyser disappears. [player] -> [JACK Rack with SBP] -----+----> [recorder] | v [Jaaa] If it's really mains hum, then you can probably just cut the frequencies below 130Hz or so. -- Adam Sampson <ats@xxxxxxxxx> <http://offog.org/>