Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[hylics]

Default HPF and LPF in DSP chain has Butterworth slope approximation. As far as I know, this approximation should have Q factor ~0.707, -3dB point at crossover frequency.
But JRiver default HPF and LPF give this slope with Q = 1, that's confusing. How to interpret JRiver filter Q and order?
How to setup second order Bessel, other custom alignments with given traditional Q, there is some formula like for Shelving filters?

[mattkhan]

https://gist.github.com/endolith/4982787 might help for emulating Bessel filters or use convolution. However if the Q values are unconventional then it will probably be tricky to get right. I think you will need a developer to tell you exactly how it uses that value, I know a shelf filter is defined using S (but labelled as Q) but haven't looked into variable Q low/high pass.

[hylics]

Thanks for this general topic. I agreed that I definitely need developer help to know what exactly Q mean for variable Q passfilters. And I believe this information would help other users prevent confusing mistakes. For example I did subwoofer intended to use with advanced analog correction, which I approximated in CAD by general 1,2-order pass filters with variable Q, but didn't achieved expected result.

How to raise this question to developers?

[mattkhan]

Just by posting here and hoping they answer