Why does the right front speaker on my Sony home theater system hum?

There could be other reasons, but I would go simple first. I suspect you have a bad cable leading from your DVD player to your processor. Try switching the left and right outputs from the dvd player. If your hum switches sides, you have located the problem. Buy new cables. Here’s a hint: the cables that come with most gear are not very good. Spend a little money on your interconnects. You’ll get better performance.

Now, if the cable swap does not isolate your problem, the issue is probably more complicated. Sometimes this “hum” is caused by interference between cables that are too close together. Try separating your cables. Sorry to be repetitive, but this problem might still be solved by buying some better quality cables. There is something known as shielding in sound transmitting cables. You might eliminate the problem with better cables.

You could try switching your dvd outputs to a different input on your processor. If that fixes the problem, your Sony HT processor is the problem. Sony puts out some OK gear, but it also sells a lot of mid-fi trash to gain market share. If you bought a $500 HT-in-a-box, well. . . .you get what you pay for. This might be covered by your warranty.

If swapping inputs on your processor/receiver doesn’t fix the hum issue, the problem is probably in the DVD player’s output stage. You won’t be able to fix that yourself. Bring the player back to where you bought it. These players have gotten very cheap. Again, you get what you pay for.