This reminded me that if the audio device is
communicating over the usb
bus it should perform better if the sample rate is divisible by the period
size.
So if you use 48000 try a period size of -p48 or -p96, etc...
Another possible assist is documented here:
http://alsa.opensrc.org/Usb-audio#Tuning_USB_devices_for_minimal_latencies