Found my problem, so thought I’d share.
In DVD architect, under project properties, there is an audio default setting. in my DA 5.0 it was set to PCM, in the new 5.2 it was set to AC-3. Changing to PCM made all the difference.
Apparently AC-3 is a compressed format resulting is a less pleasing sound quality (I’m not an audiophile), whereas PCM is uncompressed and much clearer and louder. I’m fine for now.
Tom