Re: [SoX-users] sox is muffling the track if a small frequency range is muted

[Ulrich K. <ul...@ch...>]

Jan Stary <ha...@st...>:

> On Dec 01 22:34:22, Paul Hemans wrote:
>> Hi, I am trying to notch out a frequency from a sound track
>> using the equalizer. It is working, but it is also affecting
>> the dB levels of the other frequencies in the track.
> That is strange.

No, I don't think so. :-)  "the bandwidth in octaves (between -3 dB  
frequencies for BPF and notch or between midpoint (dBgain/2) gain  
frequencies for peaking EQ)"  
(http://musicdsp.org/files/Audio-EQ-Cookbook.txt)

> equalizer 6775 0.125o -90

As this is peaking EQ, the attenuation is still -45 dB at the edges of  
the given bandwidth.

To notch out something, better try a notch filter ("bandreject"),  
where it is -3 dB only at the edges. "sinc" can also be used.

> Use the --plot option to view the transfer function of your equalizer.

That's very good to see the difference.

Ulrich