bpm fluctuation

[Gyorgy Sagi]

I use MixVibes DVS v2 vinyl with Mixxx and the pitch goes up and down randomly.
This way it's really hard to use Mixxx, without accurate bpm display.(about +/- 0.15 - 0.20 flutter)
I tried Mixvibes Cross, and it displays bpm right, so vinyl and vinyl player is ok.
I found a forum topic, that others have the same issue under OSX, with other types vinyls also.
http://mixxx.org/forums/viewtopic.php?f=3&t=5331&hilit=bpm

I also made a video:
http://djdue.com/other/bugreport.mov

System:
Mac OSX Maveriks 10.9.2
Intel Core i5 2.3Ghz
8GB RAM
2 simple USB soundcards(used with default 11ms latency)

[Gyorgy Sagi (due)]

I forgot to mention, I used the latest Mixxx 1.11.

[Gyorgy Sagi (due)]

another thing: only the displaying fluctuating, the music itself doesn't.

[jus (jus)]

Other software might just smooth out the fluctuation in the timecoded signal coming from your turntable, and update BPM display less often as we did.

We slowed down the bpm display update rate to only 4 times per second for the next version.
Marking fixed for now.
Please test once we have the v1.12beta available and report back.

Follow the fix & the interesting discussion @https://github.com/mixxxdj/mixxx/pull/149

[Owen Williams (ywwg)]

We already smooth out the signal and update the display less often. any more smoothing and the vinyl becomes very unresponsive. Your other software is lying to you. I can even see the dots on your turntable gently moving back and forth -- welcome to analog!

Also your signal looks really dirty, the ovals should be nice and round. Clean your needles and adjust the incoming gain until they are round.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/7475