Install SOX from brew and use the following
cat /dev/urandom | sox -traw -r44100 -b16 -e unsigned-integer - -d
-traw Tells sox to consider incoming data as raw, uncompressed audio.
-r44100 Sets the input sampling rate to 44.1 Kiloherz.
-b16 Tells sox the bit-depth for this audio stream is 16 bits.
-e unsigned-integer Says that the raw data should be considere an unsigned integer. (Which are the kind of numbers /dev/urandom outputs.)
– This stray minus sign is very important! It tells sox to take the stream that was piped to it as a source.
-d tells sox to use the ‘default’ device for output.