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I own a VARO FL-3D Flutter Meter designed circa 1958. It seems to have been the standard in the audio industry for making wow and flutter measurements. I obtained mine from a radio station (WVNJ AM) when it went out of business about 20 years ago. It is all miniature vacuum tube based and has a lot of tubes to perform it's function. Interesting, it was a standard used by the US Military for such measurements of audio recording and playback devices including tape, wire, optical, and disc recording. My unit still works, but the cal sticker is 1972. so who knows it's accuracy. It does work in that I have recorded a 3000 Hz signal on a known tape deck having a known specified wow and flutter and this VARO gives similar results to its spec.
Most interestingly is this statement from the product user's manual (from the Military)
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".....thus, two problems are interposed: (1) the difficulty of obtaining a disc or film record that is actually on 3000-cycles, and (2) isolating the flutter of the recording media from the flutter of the playback media. This is to say that it is extremely difficult to make a record in which the flutter recorded into the record is less than 0.1"%". Also, it is less difficult a problem to make a disc playback turntable with flutter less than 0.1% than it is to make a recording system with an equivalent flutter level; this is true simply because the variable force components of a disc recording system are much greater than in the equivalent disc playback system."
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Craig
Most interestingly is this statement from the product user's manual (from the Military)
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".....thus, two problems are interposed: (1) the difficulty of obtaining a disc or film record that is actually on 3000-cycles, and (2) isolating the flutter of the recording media from the flutter of the playback media. This is to say that it is extremely difficult to make a record in which the flutter recorded into the record is less than 0.1"%". Also, it is less difficult a problem to make a disc playback turntable with flutter less than 0.1% than it is to make a recording system with an equivalent flutter level; this is true simply because the variable force components of a disc recording system are much greater than in the equivalent disc playback system."
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Craig