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Article Index
Adjust+ Part II
Speed accuracy / Wow & Flutter
Arm Low Frequency resonance
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SPEED ACCURACY / W&F

Speed accuracy is a fairly straightforward measurement, where a 3,150Hz tone is read from a track on the test LP. If it reads 3181Hz then the player is running 1% fast and Adjust clearly displays error in large numerals. Turntables usually have an error of less than 0.5%; anything greater indicates there is a problem.


wfplc5901


Wow and flutter of the Pioneer measured 0.11% according to the Adjust analyser and disc.

Speed error was negligible at 0.005%, because this is a quartz-locked Direct Drive.



Wow and Flutter refer to variations of speed, Wow being slow variations below 10Hz and Flutter fast ones above 10Hz. Interestingly, Flutter is analogous to digital Jitter, both being variations of frequency, or frequency modulation. Adjust+ gave a reading of 0.11% with our Pioneer PLC-590, a little higher than our Rohde & Schwarz UPL audio analyser with DIN weighting selected, playing test LP DIN 45 545 Gleichlauf-Mess-Shallplatte ('synchronisation measuring record', Babelfish says) that recorded 0.07%. So the Adjust+ result is close to professional test equipment. Adjust+ say the result is weighted and the disc has a residual wow and flutter value of 0.03%.


adjustwfofplc590

Wow and flutter of our Pioneer PLC-590 test turntable measured 0.108% according to our Rohde & Schwarz UPL analyser, using the Adjust disc.



To get a meaningful reading, the LP must be centred so the arm isn't swinging in and out and professional test discs usually have an outer locked groove for this purpose. The Adjust+ disc lacks this so it has to be centred visually in an ad-hoc manner. When I placed the disc off-centre deliberately, the 0.11% result rose to 0.2%, illustrating how a large wow component at 0.55Hz due to disc eccentricity will affect the result. Even without a locked groove, the Adjust system has sufficient resolution and accuracy to give a meaningful result, showing just how well a turntable is holding speed and whether maintenance is needed. Again, this is an impressive result, because cutting lathes in themselves can suffer speed variations that will affect any disc that is cut, but the Adjust+ disc avoids this problem.



 

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