Oh great, another dither discussion
I NEVER found UV-22 to be a highly-resolved dither (in the sense of revealing the depth and dimension of the source). UV-22 was for me one of the biggest hypes ever made. I performed a "dither wars" comparison about 6 years ago that convinced me and the other half-dozen participants in the shootout of the inferiority of UV-22 to a decent noise-shaper. However, compared to an indecent noise shaper (earlier models), UV-22 made a lot of sense as it was pretty neutral tonally.
Today was a unique day when it came to dither; choice of dither really mattered. Most days it's just a plug and play thing and no one (including me) makes a fuss as long as it's a "name brand". But today I had a client over and a particular project where the flavor of the dither turned out to be VERY critical. It was a classical piece where a lot of attention had been made to the depth and the width, and was recorded and then mastered by me at 96 kHz. The reduction to 44/16 is a loss, and the choice of dither that we ended up with was always a compromise with no absolute winner. The four dithers under consideration were: POW-R 3, POW-R 2, and Waves Ultra (9th order) as implemented in the L2 (threshold set to 0 dB so no limiting action).
Tonally we liked the Waves dither best, it was pleasant and very pure, with POW-R 2 being second, and POW-R 3 being third. POW-R 3 sounded a bit grainy or a hair bright on the soft and delicate material, but on the large full orchestra, voice and organ it sounded fine and not bright to us. However, we settled on the POW-R 3 because it revealed the most space and depth overall and spatiality and depth was the client's priority. If spatiality were not the client's priority we would have settled on the Waves. And if it were not such a nuisance to switch dithers, we might have used the Waves on the soft material and the POWR-3 on the louder and more spacious material.
This judgment is VERY material dependent. You need to become familiar with how the dithers you are considering react with different material as they are all compromises compared with the 24 bit original. On some material you can hardly if at all hear a difference. But with this soprano singer whose sibilance and high frequency character had to remain pure, POW-R 3's tendency to be a bit bright became magnified with this material. Although with most material lately I've been choosing POWR-3 almost by rote, and if there is any question of whether the tonality is getting grainy or bright, switch to either POW-R 2 or the Waves Ultra, as either one is excellent.
With less critical material, I would say either POW-R 2 or Waves Ultra is your safest bet if you don't want to spend much time deciding if there is a downside. That's the newer, 9th order Waves, by the way.
I personally am not a fan of flat dither unless depth and dimension is not important to you. There are others who will argue that flat dither is all you need---but on critical material I do hear these difference------if you care about depth and dimension and ambience, then choice of noise shaping is critical. If you don't, or if you think that all noise-shaped dither sucks, then go ahead and use flat dither.
