I'm working with rosegarden, ardour, qsynth recording my rakarrack output ,
but rosegarden, and ardour work now with 48000Hz
and rakarrack seem to work only with 44100 Hz
is there a way to use rakarrack with 48000Hz ?
This is strange. Rakarrack works with any arbitrary sampling frequency, and even recalculates all sampling-frequency-dependent parameters internally. Whatever the jack sample rate is, that is what Rakarrack uses.
Probably you will need to explain what happens when you attempt to use Rakarrack at 48kHz. I use Rakarrack at 48kHz all the time, so I know it works at least on my computers ;)
Are you changing the sampling frequency during your recording session?
As Ots says that he is using qsynth, maybe he got things mixed up? In qsynth, you need to set the same sample rate as in jack. It has nothing to do with Rackarrack but I chime in with this note, just in case.