How important is low W & F performance anyway?
I recently completed work on a direct drive motor controller for a turntable mfr with IMHO, rather impressive results (0.004% 2 sigma method, 0.002% RMS). In measuring other tables actual performance (vs published specs) I was shocked at the rave reviews two tables received that have rather lousy measured performance (but impressive specs). It made me wonder whether the goal of ultra low W&F performance was really necessary? I trust the measurements as they were verified by several methods and software tools and they correlated rather closely, yet the reviewers almost universally praise these tables. It made me wonder if the reviewers even know what they are hearing or listening for and not to put to fine a point on it, does it even matter?
Dear @phoenixengr : " It made me wonder whether the goal of ultra low W&F performance was really necessary? " Whi asking for that goal? along the title of your thread and what you posted in your answer to my question makes me to think why are you asking those questions?
No ofense but makes to me no nosense.
R. |
Because having spent a great deal of time and effort to achieve that goal seems to be all for naught if tables that measure much worse are perceived as desirable and receive universal praise; it makes me wonder if we were chasing the wrong goal. I likened it to the specification wars of the late 70’s and 80’s for ultra low distortion figures in amplifiers that turned out to be a false beacon in the night. Apparently engineers and audiophiles think very differently about things. |
Fascinating topic I have a venerable idler-wheel Garrard 301 and a new belt-drive Holbo air-bearing system. I don’t have pitch perfect hearing and I’ve never noticed wow or flutter on either of these decks. The Garrard's speed increases very slightly from cold over about 10 minutes before attaining its stable speed - something noted in the original manual for pitch sensitive applications. Garrard specifies wow and flutter separately - wow less than 0.2% and flutter less than 0.05%. Furthermore, Garrard specifies exactly how these have been measured - using a Gaumont-Kalce Wow and Flutter meter Type 564 with 3000 cycle constant frequency records at 33.3, 45 and 78 rpm. Very much an analogue device, one of these meters popped up for sale recently for $400, but how would you know if the meter itself is correctly calibrated? Each Garrard was delivered with individual hand-written test results for wow and flutter at each of the three speeds - six numbers in all. On the other hand, the Holbo does not seem to include wow and flutter in its specifications at all. With a 5-kg platter and an air bearing, it is pretty free-running. If the belt is removed, it takes about three minutes to come to a stop from 33 rpm. A review of the Holbo Holbo Mk2 Airbearing Turntable System | Tracking Angle includes so many speed stability measurements that my head is also spinning - from 0,116% peak W&F to 0.016% WRMS (weighted root mean squared). Here is the nub: what weighting curve is used? It varies depending on the particular standard you choose. Most of the European-centric standards seem about the same, but the Japanese are quite different. Couple this with the wide variety of averaging methods - peak, standard deviation, two standard deviations, root mean square, average and simple numbers could mean almost anything. From what I’ve read, wow and flutter is most likely to become apparent on solo piano recordings. A reverberant listening space might allow the decay from a note to interfere (beat) with a reflection of the same note emanating at a slightly different speed. I’ve never noticed this, but have not been listening for it either. |
