Comment 6 for bug 849464
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| Owen Williams (ywwg) wrote Re: Vynil control Issue, pitch stability | #6 |
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1b1ed1a
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One thing that doesn't quite make sense in your analysis is that the pitch is varying above nominal, but the sine output is measuring low. If the pitch were being interpreted as too fast, it should sound higher, not lower, than 1Khz.
But just in case, I did the same tests you describe. On my turntable (in quartz-lock mode), I do get pitch variation, but it's on the order of ~.20%. Not 20%, 0.20%. So the pitch is hovering in a range of .9990 and 1.001 -- this seems acceptable to me, and makes sense considering the analog and always-warped nature of vinyl. (In the Mixxx UI, this shows up as -0.10 and +0.10.) I get my peak frequency at 998.99Hz -- again, perfectly acceptable.
Looking at your screenshot, I see that the signal shape is warped. It should be a perfect circle, but I'm seeing a lopsided oval. This usually indicates a needle that isn't hitting the record in a level fashion. See if you can get your signal to be circular and see if that helps the problem.