[Alessio Degani]
With my sound card, is impossible to set jack to run
at 8 kHz.
[...]
What can I do to test my algorithm at 8 kHz in
realtime using jack?
Jack does not support multirate processing, so you'll have to do the
down- and upsampling in your client. For a C application I'd look at
libsamplerate first.
Cheers, Tim