Have you tried to use the names for your alsa devices,
f.i. pd -alsa -inchannels 24 - outchannels 24 -alsadev rme9652 For this you probably need to fiddle with buffer sizes.
or -alsadev plughw:1,0 combined with different number of channels.
Or from looking at your asoundrc just use -alsadev dsp1
It seems that using the number in stead of the name means pd tries to access the hw instead of the plugin layer for rate and format conversion.
Hope this works, it works for my rme96 card.
Gerard