question about technics pitch fader with traktor

[Raver Ste]

Is it normal for my bpm to always jump around 0.20 for example it will be at 125.40 to 125.60 and just jump between them. this is really annoying

does cdjs just lock at 125?

[Irrational Fear]

Isn't this simply because the software is attempting a digital (Traktor) interpretation of an analogue (Technics pitch fader) signal?

Also as the bpm is calculated based on the speed of the playback of the record, it is going to be sensitive to any slight variations in the rotation speed etc. This is noticeable in the software as the continual bpm fluctuations you mention.

With CDJs, the pitch is digital and so if you select 125bpm on the CDJ the track will be playing at a constant 125bpm until you move the fader to another position. Consequently, if the CDJs are hooked up to Traktor there will also be no bpm variation.

Another difference worth pointing out is the response time to BPM adjustments within Traktor. When using CDJs, the pitch fader on the CDJs is mapped directly to the pitch within Traktor- so as you move the fader there is absolutely minimal delay (particularly in HID mode) therefore;

-The BPM display in Traktor is seen to be 'driving' the speed of the track.

With analogue turntables, there is no 'midi' signal being sent from the turntable's pitch fader to the software. The only signal comes from the speed of the record playback itself, therefore;

-The speed of the track is seen to be 'driving' the BPM display in Traktor.

Therefore when using turntables, the visual BPM display in Traktor changes AFTER the actual BPM has changed. Obviously this delay is minimal, but it took me a bit of getting used to when I first started using DVS.

When using CDJs with Traktor you don't get this and so any adjustments to the pitch fader feel much more 'instant'. And obviously with a digital pitch you get a constant read-out with no fluctuations.

That is my understanding of it all anyway!

If someone can find a more concise/technical way of explaining what I have basically vomited onto the page above then that would be appreciated!

[Patch]

Wow and flutter.

[DJAdeSands]

Irrational Fear's detail is pretty in depth there! To add to Patch's answer too, the problem with analog(ue) signal with digital tech is apparent. The software takes the soundwave on the record, uses this tone to determine the pace of the track, so if you speed it up, the pitch increases, etc..The software detects this change in pitch, and adjusts the pace of the track accordingly. The 'wow and flutter' are small variations in the speed/pitch of a vinyl record, and it changes the pitch ever so slightly. This isn't a problem with your deck.. this issue has been apparent with analog(ue) media since day one.

[3heads]

0.2 bpm does sound like a rather large amount of wow and flutter, though, especially for 1210s. My memory might deceive me, but what I'm used to is more in the range of 0.05 or something like that.

[Hippie]

Have you got Stable BPM enabled in the deck preferences?

[djrickdawson]

I have always had the BPM from timecodes running on my technics 1210mk2 decks to always show .02 BPM less than the track actually is.
138 shows 137.98
140 shows 139.98
145 will be 144.98
and so on.

anyone know why?

and yes my decks are calibrated.

[Raver Ste]

thanks for the replys