Hi,

I have a Beovision 7-55 and two BL5 as frontspeakers and two BL4000 as rearspeakers. When I look at Cable-TV through my SET-TOP-BOX (using HDMI-cable) I have a soundproblem. 

Problem: When I swith channel from a DolbyDigital-channel to a non-DolbyDigital Channel I hear a humming noise from left speakers. What I mean is that when the the TV:s surroundmodule goes fron DolbyDigital 5.1 to PCM 2.0 then the humming noise will be heard for about 1-3 seconds. If you have the volume at high levels on the TV, the noise could be very high.

The problem occurs just when the surroundmodule goes FROM Dolbydigital 5.1 to a PCM-sound. You will not hear it when the module goes from PCM to Dolby Digital.

I had a Beovision 7-40 Mark III before and I did not have this humming noise.

I know that it is not a problem with the settop-box because I can hear it also when I am looking at DVD:s through my Bluray player. I can hear it when I swith soundtracks between DolbyDigital 5.1 to Stereo (2.0 PCM). The noise will only occur when I go from DD 5.1 to PCM, not the opposite way.

Can anyone try this on your BV 7-55 or your BV 7-40 Mark IV and see if you have the same humming noise in your left speakers. I suppose the 7-40 MarkIV has the same DSS-module inside (DSS module Mark 2.5).

Regards
Martin