How would i convert a bandwidth of say 30kHz to bps if I only know the number of bits per sample (4)? (and I was using a two chanel system). I am assuming it is simply 30KHz * 2 * 4 but this may be wrong
You haven't mentioned what the sampling rate is. According to the Nyquist Rate, you'll need to sample at twice the analog bandwidth to achieve alias-free sampling.
So assuming you want 60 kHz sampling, your total data rate will be:
60 kSamples/sec * 2 channels * 4 bits per sample = 480 kbps.