Very curious. I've not heard anything like this from mine, but I also never use DSP's. Could you maybe elaborate a little more on the problem? How did you determine it was digital distortion? Is it only when using a digital input? What does the distortion sound like? Is it a humming or a crackling or something else all together? Which surrounds? When I hear center and surrounds, that sounds like everything but the sub, is this correct? More detailed information on the problem and any troubleshooting you did may give some of the more experienced individuals around here what they need to solve your issue.