I noticed recently that I had to keep raising and lowering the volume because the dialogue in movies was coming through softer than the additional audio tracks. Nothing has changed on my setup. The audio source is 5.1. If I run a simple 5.1 channel test (for L/C/R as this is a 3.0 soundbar of course) I hear the audio in each respective speaker just fine, however the center channel is about 50% quieter than the L/R. I've tested this on multiple audio sources including a proper 5.1 reference disc. The soundbar is a year old.