Blu-Ray Sound Problems

Hi, hope I have the right forum!!

I have a Samsung Blu-Ray player connected to a Philips HD LCD via a HDMI cable. I have noticed a problem with sound. When watching an film where the shot has background music / Sounds, then the speech is barely audible.

I do not have any surround system installed, so if anyone has any hits for improving the quality, I would be very grateful.