I've been having the following problem with my TV for a long time now & I've upgraded several times to new firmware, expecting it to get fixed but it never did.
I have a HTS5591/12 hooked up to my 46PFL7605H/12 through HDMI. Whenever I insert a DVD or Blu-ray disc, it takes about 5 seconds before any sound comes through. This also happens when for example I go to the disc menu & select the Bonus features. When it starts, again 5 seconds before I get the sound. Going back & forth through chapters gives the same problem, when starting a chapter I need to wait 5 seconds before I get audio. I have to rewind the 5 seconds every time to hear the dialogue. This is also pretty annoying when I eject a disc & want to look to the rest of a movie a bit later.
This also occurs with my digital tuner & my XBOX so it's not HTS related. They are all on different HDMI ports, using different brands of HDMI cables. I've tried hooking up my equipment to my older television & there I get sound immediately with all of my equipment.
I really hope Philips will resolve this problem soon, it's been a day one annoyance & contacting Philips by phone or mail never provided me a solution...
Please see your PM from me.