I have a sound file that I need to apply a notch filter to in Matlab.
comparing to original file I have two frequencies which are the noise. Applying a notch filter like this one:
wo = 1750/(44100/2); bw = wo/35; [b,a] = iirnotch(wo,bw); fvtool(b,a); f1 = filter(b, a, f);
This will atenuate the frequency at 1750 Hz. However there is one more frequency that is causing trouble at 820Hz. What I can do is reapply the same notch to the "new" version:
wo = 820/(44100/2); bw = wo/35; [b,a] = iirnotch(wo,bw); fvtool(b,a); f2 = filter(b, a, f1);
and f2 will be my clean file. However I need to have one vector "b" and one vector "a" that will clean all the noise at one go. Can I apply two notches simultaneously? I am very new to this kind of stuff. Thanks