I'm not sure I understand. Which sounds better? The DTS? I agree it is strange if the compressed DTS sounds better. What was the original hi-res source? 24bit/96k? My guess it is the conversion from 96k that is the culprit. Converting from 96k to 48k is a much easier conversion than to 44.1. Perhaps try converting to both 24/48k and 16/48k. I expect you won't notice a difference unless dithering is poorly implemented in your DAC.
Don't misunderstand my previous comments. I prefer all my music hi-resolution and uncompressed if it was handled correctly from recording through mastering. I was just trying to explain that 24 bit isn't necessarily better, and a 24 bit sample size isn't necessary with most modern music which is absent of dynamic range. However, if it was recorded, mixed and mastered at 24bit, then I'd prefer to avoid the conversion and have it delivered to me at 24bit too.
Sadly, I've bought too much music from hdtracks that sounds no better, and many times way worse, than CDs I already own. High res does not always equals better sound quality.
Again, sorry for being off topic.