There are several different low pass filters, and as many high pass, band pass, band stop… filters. In Audio toolkit, there are different usual implementation available:
- Chebyshev type 1
- Chebyshev type 2
- Second order
and it is possible to implement other, different orders as well…
Here is a display of the behaviors of these filters (for order 2 for those who can have different orders), amplitude and phase:
What is interesting is that for low pass filters, the Butterworth filter is the same as the second order filter implementation. Linkwitz-Riley filters have a lower amplitude than the others, and Chebyshev type 2 has definitely a different behavior than all the others (which is due to the fact that its prototype is different than for the others, it’s not based on band pass, but band stop).
With all these options, I think Audio Toolkit can cover any basis.