what tool preforms best downmix conversion. I have noticed many DVDs have dual mono, simply downmixing the audio sounds bit mettalic or robotic, perhaqps because the channels are slightly phased.
I need to preserve the quality of original track, what do you recommend me?
You want to downmix from 2-channel stereo (or Dolby surround) to mono?
...perhaps because the channels are slightly phased.
If it's truly dual-mono there shouldn't be any phase differences.
If there are only
phase differences, you don't need to downmix... Just choose one channel and use that as your mono channel.
If it's stereo and there is "phase weirdness" (i.e. comb flitering) when you downmix, there is no solution.