Turn table speed variation question


I've always found that tracks containing sustained piano notes (chords mainly) seem to highlight the smallest variation in platter speed.

However, I do not notice the same speed variations with sustained notes played on any other instruments.

Works well when auditioning turntables, but a PITA when you hit those older, less than stellar recordings, where the tape machine cause the issue.

Wondered if anyone else had the same experience with a different instrument, or is this specific to the piano.

Thanks
williewonka
Dougdeacon, you are correct in your description of the harmonic
characteristics of period vs modern instruments. The opposite is believed
to be true by some (including some musicians) because modern
instruments' apparent brilliance is sometimes assumed to be the result of
increased harmonics (relative to the fundamental), when what is often the
case is the absence (or decrease) of specific harmonics due to
manipulation in design giving the sound a less complete harmonic
structure. This less complete harmonic structure can highlight upper
partials and give the modern instrument an edgy or "brilliant"
sound. The denser, sweeter sound of many period instruments is the result
of a more complete harmonic content.

I am not so sure about your contention that this more complete harmonic
structure would make the sound of period instruments more susceptible to
a tt's speed inaccuracies as all frequencies would suffer to the same
degree. However, you are quite correct about original instrument
recordings being an "acid test" for speed stability. But, IMO, the
main reason for this is what I pointed out in my previous post; the presence
or absence of vibrato. Music performed on period instruments normally is
played with very little or no vibrato. When this music was composed,
performance practice dictated very very sparse use of vibrato; only as an
occasional color as opposed to the constant use of vibrato that is common
today. The reason for this is that, for instance, a modern violin played with
no vibrato will sound louder than an original one, but dry and lifeless
because of (as you pointed
out) the diminished overtone content.
Thanks everyone for the input - I now have a very good understanding of possible causes - never thought about the off-centre hole - good one :-)

I had always thought it was due to the tape ,machine used in the recording process.

I can see how the pure pitch of a long note and the associated harmonics would contribute to the immediate identification of speed variations - to these ears anyway.

Thanks again for the input - very enlightening.
"Lew's right.
Any stringed instrument is particularly sensitive to minute speed deviations.
When I listen to acoustic guitar on my Victor TT-101 DD turntable with unequalled speed accuracy......an off-centre record hole will be mercilessly exposed. :-(" - Halcro

Not to digress too far, but since the thread is about speed accuracy, I do believe the word "unequaled" may be a contentious one. I doubt if the Victor is unequaled, however. What measure of accuracy is it?
How about "rarely equalled"?
But it was not I who made the claim re the Victor, altho I am sure it is excellent in respect of speed stability.

I do believe the word “unequalled” may be a contentious one.
Perhaps I should have elaborated….but this has been discussed in other Threads on turntable speed accuracy and I did not wish to complicate this one?
The JVC/Victor TT-101 has pretty good specs….
Wow and Flutter- within 0.02% WRMS
Speed deviation- 0.002%
Load characteristics- 0% (with a 120g total tracking force)
Drift- 0.0004%
But to me….printed specifications are meaningless when it comes to ‘actual’ performance in relation to speed accuracy and consistency?

Until recently…the concept of ‘stylus drag’ on the speed performance of a turntable…was treated with scepticism.
Then Ron Sutherland introduced the Timeline….a laser-flashing ‘puck’ which sits over the turntable spindle and has a time-base accuracy of 2 parts per million.
With this device installed………..it provided scientific evidence of the phenomenon of ‘stylus drag’ as the laser spot was seen to drift the moment the cartridge hit the record with most turntables….especially belt-drive ones.
The very best belt-drive turntables have reportedly been able to
maintain the stability of the laser dot of the Timeline…..when the speed has been adjusted with the cartridge already tracking the record. But then it is ‘out’ of adjustment when no record is being tracked?
I have not witnessed any visual evidence of these accomplishments…..they are merely empirical claims.
I have not seen nor heard of any claims regarding the speed accuracy of Idler or Rim Drive turntables using the Timeline under ‘stylus drag’ conditions.
I have tested the TT-101 under all conditions…..with and without ‘stylus drag’….and the laser dot of the Timeline does not deviate.
TT-101
This test has not been reproduced successfully with 3 arms and cartridges on and off…..with any other turntable to my knowledge?
Hence my statement?
If your turntable can match this performance…..please upload the evidence to YouTube and I will revise my statement to ‘equalled but not exceeded’……:-)