Where can I find good tutorials on writing audio DSP filters (lowpass, etc)?
By : Adil Jadoon
Date : March 29 2020, 07:55 AM
I hope this helps . The link you really want from MusicDSP is http://www.musicdsp.org/files/AudioEQCookbook.txtI also recommend getting Lyon's Understanding Digital Signal Processing. I am a bit biased, though, since I was a reviewer for the second edition (but I think a third edition came out recently).

Matlab 3 dB 12 hertz lowpass filter
By : Henke van den Boer
Date : March 29 2020, 07:55 AM
With these it helps For your application I would strongly recommend trying a plain butterworth filter, the Matlab syntax is: code :
[b,a]=butter(n,Wn)
% assume x is time and y is speed
Ts = mean(diff(x));
Fs = 1/Ts;
% for butter, we need Wn, which is the cutoff frequency
% where 0.0 < Wn < 1.0, where 1.0 is half the sample rate
% The cutoff is the 3 dB point of the filter
% Wn = fCutOff/(Fs/2)
% for a cutoff of 12 Hz
fCutOff = 12/(Fs/2);
% we'll start with an order of 1 which should give us about 20 db/decade attenuation
[b,a] = butter(1,fCutoff);
% plot the filter frequency response to see what it looks like
% use 512 points to plot it
freqz(b,a,512,Fs)

Equivalent function in python for MATLAB's lowpass() function?
By : user3422657
Date : March 29 2020, 07:55 AM
wish help you to fix your issue Scipy is probably the best tool for this. You can use scipy's signal processing libraries. From their docs, they even offer matlab style filter desing.

what is the theory behind matlab butter function?
By : pavan kumarSp
Date : March 29 2020, 07:55 AM
like below fixes the issue I assume you've looked at the Matlab help page. Background

Issues with MATLAB butter
By : P.Gaur
Date : March 29 2020, 07:55 AM
I wish did fix the issue. Just a guess but is there any chance you've defined your own poly function? which('poly') should point to some Matlab directory unless you've defined it elsewhere, potentially as a variable?. For me on a newer version that path is something like $MATLAB/toolbox/matlab/polyfun/poly.m You can also edit the poly function edit poly and verify that there is one output argument for the function. Also, I'd advise against ever writing decimal numbers without a leading zero. It took me way to long to figure out what [.15,.3] was. Instead write [0.15,0.3] or even just [0.15 0.3] Edit: I just realized that is an example in Matlab ... my point stands but the toolbox author should know better ...

