I am working on trying to apply a low and high pass filter to an audio file that contains a set of exhalations over a microphone. The inhalations have been cut out of the file, and the exhalations are stitched together in the file. I am attempting to replicate this paper where they have set 10 and 150 Hz cutoffs on their microphone data. I have attached the relevant portion of the paper at the end of the post.
I am currently following the code linked at this DSP stack exchange post, but am unclear on what an appropriate measure for the 'order' parameter would be when using the Butterworth bandpass filter. Currently, with an order of 5, it seems to filter out all of the audio from the .wav file... what is the effect of the order on the input data?
The end goal is to perform a spectral analysis on the filtered data. The unfiltered file can be found here.