Why three motors?

Hi Hiho, well - thanks for posting those three 3-motor-drive contenders. They all share the very same set-up - as far as geometry goes. All using a 3-side-symmetrical approach. Somehow logic and going along with the common sense of mechanics in providing a force-vector free bearing in the horizontal plane. I guess we still haven't found the true idea behind the Raven's 3-motor-drive.

I have read a thread in the past Clearaudio with 3 motors sounded best with only 1 belt. this guy has experimented with all possible configuration and found the sound to improve significantly with only 1 belt. his hypothesis was 3 motors + 3 belts variation is higher than 3 motors + 1 belt variation, therefore using 1 belt vs. 3 reduces the overall variation produced by the drivetrain. YMMV.

I really should have changed the titled question from "Why three motors?" to "Why such belt arrangement?"

I am less interested in why using three motors but in why they arrange the belt in a 3-motor design that only one side of the belt is touching the platter.

If they use four motors, the belt would not touch the platter at all! Perhaps that's the best sound in having the blackest background.

Syntax: "Simple answer: That's Higher End"

So far that's the best answer.

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When I first saw such a turntable, the arrangement of the belt struck me first, and I admit not particularly considering the motors. Now that the question has been properly framed, I don't really understand the principle of three motors, but I do get the belt arrangement. It does have something in common with an idler in that it mandates a smaller contact area with the platter, or footprint. This may in turn alleviate belt creep to some degree, and I have come to believe that belt creep affects micro dynamics by smearing the music at a subtle level. It is one workaround, but other belt drive makers have other ways of accomplishing the task.

A notable example is the Artemis Labs turntable that Frank Schroeder designed. It uses a spring loaded pulley to help control belt creep, and at the same time it serves as a noise canceling device of sorts. A less sophisticated solution was found on the 1962 Rek-O-Kut Rondine 2. Yet another solution can be found in the Spiral Groove turntable. Its drive is configured in an optimal way that helps isolate noise and reduces the effect of creep by various positioning maneuvers.

It has occurred to me that a single motor with two equidistant pulleys might be an improvement over traditional schemes, but I build idler turntables, so I'm not a candidate to try the idea. However, a lot of you have belt drives, and are handy enough to make the modification. If one of you actually does, it may be something interesting to others.

Thanks for your idea about the belt arrangement. But I seriously doubt the designer intended that way and if he did, that's a rather belabored effort to achieve small contact area by using THREE motors and not to mention belt slip. Oy! Why not just use an idler wheel? The manufacturer no longer has that model so I have to assume they have changed course.

There are formal reviews of the turntable and yet not one reviewer questioned the wisdom of the belt arrangement; they are the usual couple paragraphs describing the mechanics and they go straight to the epic flowery prose about the soundstage blah blah blah.

Your examples of combating belt creep is very interesting though. Thanks.

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