[pulseaudio-discuss] R: New equalizer module (module-eqpro-sink), some questions

[Alexander E. Patrakov]

пн, 8 апр. 2019 г. в 13:08, Alexander E. Patrakov <patrakov at gmail.com>:

> I have looked again at the paper, and have a DSP question.
>
> The thesis starts with designing a shelf filter. That is, a filter
> that contains a flat area at low frequencies, a flat area at high
> frequencies (but with a different gain), and some transition in
> between. Then, for some unknown reason, it is transformed into a
> band-pass shelving filter. Then there is some talk how to "stitch"
> together several band-pass shelving filters.
>
> Why would one need to do this at all? I.e., why can't one just cascade
> several shelf filters, designed according to the correct transition
> frequencies, with the height of the shelf being the dB difference of
> the desired gains of the neighboring bands?

Just for some context: the reason why I asked is the ripple on Figure
2.5 that seems to be avoidable in my approach.


-- 
Alexander E. Patrakov