Turntable speed accuracy


There is another thread (about the NVS table) which has a subordinate discussion about turntable speed accuracy and different methods of checking. Some suggest using the Timeline laser, others use a strobe disk.

I assume everyone agrees that speed accuracy is of utmost importance. What is the best way to verify results? What is the most speed-accurate drive method? And is speed accuracy really the most important consideration for proper turntable design or are there some compromises with certain drive types that make others still viable?
peterayer
A point was stumbled upon here, but no one followed through with the observation.

Halcro noted, "...you would have seen.......about half way through the video......where he drops the cartridge on the record and immediately.....the speed decreases?
And this is only the beginning of the record. Not a heavily modulated passage?
Can you imagine what happens with a really heavily modulated passage? And that turntable in the video has a very heavy platter."

Of interest to me isn't that the speed controller, assuming there was one, is inaccurate. It may be perfectly designed; we don't know. So, what basic principle would cause the speed drop? It isn't electronics, so it must be mechanical. If that is the case, all the electronics in the world cannot fix a fault because of a faulty design in the parts that make the turntable. My point is that inertia has to be addressed at the outset of a turntable's design, and that electronic speed control merely augments it. I strongly believe that 100% success is not found unless the all the pieces work in unison.

Sure, you can improve a turntable by adding an electronic speed control. The true nature of the recording is best exemplified when inertia is a major consideration to the basic design, in my honest opinion.
Tonywinsc,
interesting what you experienced during your test measurements. on all my TTs I experience a change in speed when the needle hits the record. Regarding the different carts and weights of the headshells I usually adjust speed by my speed controllers. Belt drive not necessarily needs to be a disadvantage (thread). I usually measure my wow & flutter with a test tone of 3150 Hz and on the EMT by 5000 Hz (J60s).

You are so right on the Influence of the exact spindle position of the record. Most turntable designs don't refer to this issue. I know one design which does optimise the center of rotation - the Nakamichi TX 1000.

Best @ Fun Only

Tonywinsc -- excellent post!

I was thinking of the Nak TX 1000 as I contemplated your thoughts...Thuchan knows a thing or two -- about audio, I mean, hehe :-)

It would be fascinating to run those tests with the TX 1000 as the DUT.

Best regards,
Sam
on all my TTs I experience a change in speed when the needle hits the record.
Thuchan,
On my TT-101 there is zero speed change when the cartridge hits the record. Even with the low compliance heavy tracking XV-1s and FR-7f.
Halcro,

do you have an inbuilt realigning control unit which brings the speed always to 33 or 45?

best @ fun only