Ok, so you're starting with original Blu-ray discs. Do the original discs have any issues playing in the PS3, or are you having the sound cut out on backups you have made, or on media files (mp4, avi, mkv) that you might have made from the originals?
If you are converting Blu-ray with the AVS program you mentioned, which decrypter are you using? There are only three that are reliable enough for me to recommend, those being AnyDVD HD, DVDFab Blu-ray Copy and MakeMKV. Of those, only MakeMKV is free.
So, we need to know the process you are using. Feel free to hit us with a long post this time, with details of what you are doing.