Convolving Room Impulse Response with a Wav File (python)
The way you read the files is a little odd.  The method used here is clearer with respect to the sampling rate and the signal.
You will note that the above example calls pcm2float after reading.  This may be the cause of your problem.  The wave reader returns an array of ints.  Processing those (quite large) values may well cause problems.  Try converting your wave data to floats before doing the convolution.