ground loop would cause a 60hz hum. 60hz is the rate that AC "switches" so thats why its that.

The hiss your experiencing sounds like just plain fact that your reciever isint a top of the line model and its got some hiss noise. As alan stated, most good amps and preamps wont have this, unless you put your ear literally right up to a tweeter for example. I had a hiss which was audible in my old cheap reciever, its a way of life.

I dont see any reason whatsoever why your cables and their lengths etc would be causing this, but i would also think that you would be hearing the hiss from all of the channels if it were as bad as it sounds. Good speakers will reveal lesser equipment upstream, lesser media for that matter too. Ive been noticing distortion in movie soundtracks which is somewhat annoying.

In reply to:

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I've been noticing distortion in movie soundtracks which is somewhat annoying.

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We watched a movie last night and I noticed distortion in the center speaker. This was a scene where a lot of police cars came in with the sirens wailing. My wife didn't notice it but I sure did.

The only level adjustment I made during calibration on my speakers were Front Right +2db, Left Rear -4db and the sub I dropped to -6db per instructions that came with my SVS.

I do remember when I was calibrating and had my master volume at +13db on the readout (this was 75db on my SPL using DVE) I had a very bad hissing noise in the rears that sounded like a VERY large snake. I mean it was almost overbearing which I know affected the calibration levels of the other speakers since it was so loud.

I think I just have a noisy/underpowered amp that needs to be replaced.

Thanks guys for all your suggestions and help. Guess it's time to spend another $500 for a newer Onkyo 601.

Rick