cocoabaroque wrote:Trackside: Yes, exactly-- although I do not agree with the definition "high frequency pitch oscillation". Flutter may be within the audio band too. Anyone who has seen their Grado cartridge "wiggle" in the groove can also hear flutter in the low frequency range with oscillations about 10-20hz. Presumably, a 300rpm motor may flutter at 300hz, or multiple thereof (1200 in a 4-pole motor). If the flutter or motor cogging is mild enough, such as with the low-torque but smoother running Rega motors, the flutter is less audible.
Flutter is any pitch variation >4hz
Wow is pitch variation <4hz
Sorry but I don't believe in your theory of it masking wow however 'vibrato' is a known phenomena which some like in instruments and voices which may make the sound of a TT sweeter. A significant flaw in this theory is that a large rotating mass like an LP12 platter would need a lot of torque in the drive system to alter the speed of it's rotation at these frequencies. In short a low torque AC motor connected to the platter with a stretchy rubber belt cannot accelerate and decelerate the plater that fast. The main aim of a high mass platter is to prevent flutter. WOW however can be induced easily by any number of factors which change the speed of the stylus through the groove over a longer time frame - off centre record, uneven drag in the main bearing, loose tolerances and/or wrong viscosity in the oil causing the spindle to roll around the journal and not rotate on it's axis, uneven elasticity in the belt or belt slip, an unbalanced platter causing the suspension to rock , unbalanced suspension springs which introduce lateral movement when damping vertical input from structural or acoustic feedback. There is also dynamic stylus drag when loud or complex passages are traced. Direct drive and idler drive TT's however do have enough torque in their drives to create flutter but are conversely unaffected by most of the problems that create WOW in suspended subchassis and belt driven TT's. Flutter is not inevitable in the design though and is symptomatic of a fault. Likley a low level of constant flutter is more acceptable than wow if it creates a subtle vibrato within a tone rather than varying the tone like wow.