I have Audacity 2.1.0 and I’m trying to find a specific filter, that I was able to find in Cool Edit Pro 2.1. In Cool Edit Pro, I went to Effects->Filters->Scientific Filters. If someone could help me find the 3 things that I have circled below, I would appreciate it:
Audacity 2.1.0 is an old version. If you download the current 2.1.2 version from us at http://www.audacityteam.org/download/windows there is a Classic Filters effect that may be what you are looking for.
Note that the effect is disabled by default, so you have to enable the effect first at Effect > Add / Remove Plugins… (not Effect > Manage… as it says on the page I link to). Also due to a bug, the effect has no dB scale in 2.1.2, although the image on the linked to page shows a dB scale.
Gale
Audacity has “High Pass” and “Low Pass” filters. These are “Butterworth” filters:
http://manual.audacityteam.org/man/high_pass_filter.html
http://manual.audacityteam.org/man/low_pass_filter.html
The “Rolloff” setting is equivalent to the “filter order” where:
6dB per octave ↔ 1st order
12dB per octave ↔ 2nd order ↔ 2 pole
18dB per octave ↔ 3rd order ↔ 4 pole
24dB per octave ↔ 4th order ↔ 8 pole
For higher order / steeper slop filters you can apply these filters multiple times.
If you really want a Band Stop in one step, you can try http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Band_Stop_Filter. See how to install a Nyquist plug-in.
Gale