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1.02.2009

Blu-Ray Audio Crackle

I got a Blu-ray player for Christmas, a Sony BDP-S350. Everything seemed to be working fine, but I noticed that the audio didn't sound great. Last night we watched "Wanted", and the auction sequences were almost unwatchable because of a frequent crackle or static noise that was happening on top of all the louder effects. I spend a while fiddling with all of the settings on the player before I figured it out.

I was routing audio from the Blu-Ray player to my LG TV via HDMI. This is the first HDMI device I've owned. I guess I assumed that as long as my settings were right on the TV and player, that the TV would pass digital audio out of it's optical output to my Sony surround receiver. Well...I was only partially right. What I didn't realize is that the TV can only output Stereo PCM on the optical port. It isn't capable of passing surround. So what was happening was that the TV was receiving surround from the Blu-ray player, the TV has it's speakers turned off in the options, because I use the receiver for everything. The TV then apparently sends out a Dolby Pro Logic II stereo signal over optical. This downmixing was causing the noise. I'm guessing it was either phase cancellation between the right, left, and center channels, when they mixed, or the subwoofer effect trying to be mixed down into stereo. The fix I found was to hook the Blu-Ray player's digital audio output direct to the receiver via coaxial cable. I then went into the audio options on the player and set Coax instead of HDMI as the preferred audio output. Now everything works right and the audio sounds great. I'm pretty sure the noise I was hearing was supposed to be the subwoofer effects, but they were coming across the front channels of my surround speakers.

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