[wdfifteen]

I've had a surround sound home theater set-up for 6 years that has worked OK until recently. Now the sound from every speaker is slightly garbled, like the people talking have something in their throats. Sometimes the distortion is so slight you can barely hear it, sometimes it's so annoying we just turn the damn thing off. Our system has cable, dvd, and Apple TV inputs and the sound problem is the same on all of them. This system runs the sound&picture from the amp to the TV via HDMI cable and then the sound comes back to the amp via an optical cable (why do they do that?). We never operate it at high volumes, almost always around 25% and never more than 50%. Jiggling cable connections doesn't help. Any idea what the problem could be? I've googled the question and other people have the same problem, but no one seems to have a definitive answer.