Getting good audio results on DVDs

I am having a hard time getting good audio results when using audio files ripped from cds as the audio tracks for slideshows and such. I am using TMPGEnc (trial)…haven’t bought it yet, although I do like it.
The audio has to be upsampled from 44 to 48 for dvd and it’s also 16 bit off the cd. I’ve tried both dolby digital (which is lossy and also applies some eq) and pcm (lossless?..sounds a bit better) options but it still sounds “edgy”, somewhere distorted, or crunchy. The audio on my video tracks sounds better than audio ripped from cds. Any tips here on how to get better audio quality, and what settings to use?
I’m making musician dvds so the audio has to be good.
Thanks for any help on this.

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