I went right through the motions of taking an AC3 file, putting it into goldwave and raising the volume, converting it to WAV and then back to AC3 with Softencode. However, when I put the completed DVD-R into my standalone player the audio was exactly the same.

I had checked it both after Goldwave had converted it to WAV and after I had encoded to AC3 with Softencode and at that point the volume had been maximised. Does anyone know what went wrong by the time I burned the files to DVD????