If you simply want to get a bit-stream representation, it does not matter in any way, if the data are a wav file or a jpeg. A WAV file contains additional header information compared to the pure signal. Getting a bit-stream from it:
fid = fopen(FileName, 'r');
data = fread(fid, [1, Inf], 'uint8');
bit = uint8(rem(floor((1 ./ [128, 64, 32, 16, 8, 4, 2, 1].') * data), 2));
bit = bit(:);
Now you have a bit stream of 1s and 0s stored in an UINT8 vector. This contains the complete data of the file and does not care in any way about the contents or format.