Some different slice sizes and parameters to try and improve
JACK reliability.  YMMV depending on soundcard:

jackd -R -v -d alsa -d hw:0
jackd -R -d alsa -d hw:0
jackd -d alsa -p 4096 -n 3

I find with my SBLive the following setting works:

$ jackd -d alsa -p 4096 -n 2

Note that there is inline help for each driver but it's non-obvious
how to get at it.  For complete help on the alsa driver do this:

$ jackd -d alsa --help

