Vintage DD turntables. Are we living dangerously?

Halcro.

Perhaps you misinterpreted my last post.
When I said "perfect speed" I did not mean "perfectly centered".

A real world test record, which is off centre, produces the sine wave. Speed errors are superimposed on this sine wave, as Markus says.

So with a real world test record running at perfect speed, we would get the results I described.

cheers.

Go the ABs!

Perfect Speed?
Perfect Speed?

Just a note from the peanut gallery:
Halcro, you and Richard are actually in agreement. The statement from Feickert (or whatever was the outside source) was that record eccentricity will produce a regular irregularity in the frequency, forming a sine wave around the center frequency. Since one is interested in wow and flutter due only to tt platter speed variations, that sine wave must be filtered out or subtracted from whatever is the actual wave form. The remainder would constitute w and f due to the tt only. Ideally, that would leave a straight line, if wow and flutter due to the tt were zero. I think we can all agree on that, including you and Richard.

Lewm -
No they are not in agreement. Halcro does not accept that the deviations in the sine wave are wow and flutter ( as explained by Feickert ). Richardkrebs argued that the spikes were speed corrections generated by the TT error correction, but they could be caused by many things, all we know is that they are speed deviations.

Other than eccentricity wow and flutter can be caused by imperfections in the record surface ( you must have heard of warp wow ) and tonearm/cartridge issues. So your statement that "The remainder would constitute w and f due to the tt only" is not correct.

Dover, No one can be absolutely correct, except you. I should have remembered that from past experience. Not that I would argue with your obvious point here, your condescending attitude notwithstanding. Instead of "due to the tt only", I obviously should have written "due to factors other than LP eccentricity" or words to that effect. The point was subtracting out the sinusiodal noise due to LP eccentricity. Serenity now!