" ACCURATE AND HIGHLY CONSTANT SPEED ", ( where everything the same ) do the difference between a belt drive system against a DD system, where the DD system beats the belt drive system.
As I've followed Raul's arguments regarding DD versus belt drive turntables, I was reminded of a story Lloyd Walker tells:
At one of the CES shows, three gentlemen entered Walker Audio's room in which Lloyd was demo'ing his turntable and engaged Lloyd in a very sincere and very animated discussion about belt drive turntables not possibly being able to maintain the speed consistency needed for true state of the art performance. They raised all of the same theoretical arguments Raul presented (and rather than repeat all of these, I encourage you to read the various posts from Raul above). The substance of their point ultimately being that only a servo controlled direct drive turntable could maintain speed accuracy and resulting pitch consistency for true state of the art performance.
In the course of the discussion, all had agreed that sustained notes on a piano were one of the most revealing tests of speed consistency and consequent lack of pitch variation. So, Lloyd puts on a classical piano solo recording on his turntable and they begin to listen. Sounds pretty good, but the three gentlemen continue to argue that without servo control, no turntable can maintain pitch constancy.
At this point, Lloyd is getting a little frustrated. So, he pulls a pair of scissors out of his kit and, right in the middle of the music, CUTS the silk belt. The music continues to play. And for the next 30 seconds the piano performance continues without a motor driving it all and with perfect pitch stability.
(End of story)Personally, I'm a bit of a skeptic. So after hearing this story, I decided to test for myself on my Walker Proscenium turntable (after all, the belt is only a strip of silk tape and is easily replaced). Well..., Ivan Moravec continued to sound just luscious on some delicate Chopin for at least 35 seconds before I could detect any change in pitch here.
Cheers,