So it was an usual day. I booted the Yakuza 4 and realizied that voices sound... robotic in some way. Test gave me a hint: When its silent (in XMB for example) there is a small noise on background (like series of mini pops-like-sound) and that noise get louder with loud sounds, so it twisted all BGM and SE making it unpleasant to hear.
Problem is takes place only in HDMI mode (I have tried another two HDMI ports and another HDMI cable. Didn't tried another TV so far, but my current one is working okay with TV signal and Wii). I tried a composite cable form-the-box and sound was clear (But image, predictably, horrible.)
Can somebody throw me idea or two? I dont wanna can this baby to sony's service. Warranty should be gone now + they can update my FW. PS3 fat, 3,55 waninkoko V2
Thanks for the reply kind sir. The solution was unexpected, thought. I was about to test PS on another TV, but accidentally found a solution. Multichannel output should be on, when native HDMI sound should be off. TV need cooldown time too. I posted in case that someone will encounter same problem.