If I select Bass as the default music engine, the mediaportal appl crashes when I try to play 5.1ch M4A music. If I try the "internal Dshow" player, it works as it should. But then I loose the benefits of using the Bass engine(DSP etc)
SOLVED! I downloaded the latest aac plugin from the Bass site: http://www.un4seen.com/ Renamed the org one in the MP folder "Audio Decoders" and placed the new one from Bass. And now all my M4A files plays like a charm!