I have a Creative Ensoniq ES1371 sound card; loading the module fixed the problem :)
dur, I shoulda thought to check this at the beginning :) Thanks everyone, for all your responses. I figured this out by reading the documentation several people suggested. Aaron yomama[57]% play ~/delay/delay-ss1.au playing /home/amaxwell/delay/delay-ss1.au sox: Can't open output file '/dev/dsp': No such device yomama[58]% su -c 'modprobe es1371' Password: yomama[59]% play ~/delay/delay-ss1.au playing /home/amaxwell/delay/delay-ss1.au <speaker vibrates appropriately> yomama[60]%