Wow/Flutter Dampening (1200 control)

Discussion in 'Feature Suggestions' started by scoobycarolan, Apr 28, 2010.

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  1. scoobycarolan

    scoobycarolan NI Product Owner

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    A turntable, while very steady, does introduce wow & flutter into the speed of a track that a digital source like a CDJ will not. TSP should have a feature to dampen the wow & flutter in the tempo that is sent from control vinyl. An adjustable preference like the pitch bend sensitivity that effectively ignores the first 1/100 of a BPM change.

    I'm not sure if this already exists, if so please allow me to adjust it in the preferences. I'd be ok with giving up a small amount of touch sensitivity (the first millisecond of tempo adjustment via the vinyl) to help help keep my 1200 mixes on lock.
     
  2. lethal_pizzle

    lethal_pizzle NI Product Owner

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    So if Traktor is ignoring the actual position of the needle on the record, when it is supposed to 'catch up'?
     
  3. scoobycarolan

    scoobycarolan NI Product Owner

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    The idea isn't to ignore the position on the record. Traktor does this in relative mode. The idea is to detect the Audio 8 is set to "Control Vinyl" and the dampen, or smooth out, the very minute fluctuations in the turntables speed that prevent a tempo lock.

    If you set your pitch control to zero and play the control vinyl you'll notice that the BPM of your track will fluctuate. Say it's a 125 bpm track. It may go from 124.98 to 125.02 and waver in between. It's because a turntable isn't perfect. Allow the user select in the prefs a small amount of non-responsiveness or even disable the feature.
     
  4. DiscoNova

    DiscoNova NI Product Owner

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    Actually... even the CDs have the fluctuation the original poster described - usually it is just not as "bad" as with turntables, but can easily be within a range of +-0.05% (which in Traktor amounts to changing of the digit immediately after the comma) ... the reason for this is that the DA-converters in the CD-players are not actually running at exactly 44.1kHz (even when the pitch is reset to 0) and thus they need to keep correcting their timing constantly.

    What I'm a bit confused is; what would having the proposed feature actually achieve? I once did the math (wasn't too hard, really) ... a tempo difference of 0.04 (as stated) on a track amounts to a drift of 0.04 beats after a minute. This means that even if you're playing them on top of each other, no-one will notice anything - and this is without doing any correction during this time (ie. you don't touch either of the platters for a full minute). Of course, if you happen to be playing exactly matching beats (for example, two copies of the same song) there will appear to be a flanger-effect from the beginning, but honestly - how many songs actually have exactly matching beats anyway...

    I do think that it might be beneficial to dampen the display changes - after all, this all boils down to psychology... "because Traktor shows the speeds with such a high precision, of course there must be something wrong if the numbers don't match". Dampening the display changes could easily be accomplished by showing a running mean (average) of the last n times the timecode speed was sampled. This would - if not entirely eradicate the perceived fluctuation - at least minimise it's influence without sacrificing the actual precision.
     
  5. lethal_pizzle

    lethal_pizzle NI Product Owner

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    Yeah, just have an option to smooth the display. If your turntable is wowing and fluttering around a certain bpm then your mix will go out of time just as quickly as if you averaged out to that same bpm. Plus then you can keep your zero sticker drift.

    Traktor isn't going to be able to calculate the wow-and-flutter of your record in 1ms anyway.
     
  6. TeLLy

    TeLLy NI Product Owner Extraordinaire

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    Not sure I understand this request. If you want dead-on-no-fluctuation mixes, mix using internal play with MIDI or hotkeys. If you want to simulate turntable action, use timecode.

    With timecode vinyl I can lock up a mix and hold it for the duration of the two playing tracks. The fluctuations exist and are annoying as f*ck, but overall it does average out and like DiscoNova says, even if there is a drift of 0.04bpm, it's 0.04 beats per minute off - not noticeable to anyone.

    What I would REALLY like is for Traktor to quantize the master clock's translation of the bpm of the track being controlled. Say I'm mixing at 126.90bpm, and my turntable on the only playing deck (thus the master) is varying in tempo between 126.80 and 126.99 (I'm making those numbers up). While Traktor's bpm display for that deck shows steady at 126.89/126.90, if I load up a track in deck B or C, and using MIDI mode hit sync (I set mine for momentary, not toggle), it will grab the bpm from the master clock at that exact moment, which will be anywhere from 126.80 and 126.99. It doesn't hurt, and by the time I've got the tracks mixed out, no one will have noticed. But the fact that sync grabs a momentary tempo that is "obsolete" by the time I've let go of the button irks me. I'd prefer it grab a quantized value, which Traktor can "average out" over, say, 2 seconds' worth of play time on the timecode-controlled deck.
     
  7. scoobycarolan

    scoobycarolan NI Product Owner

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    Telly, I'm with you as an expanded function of what I'm describing.

    A CDJ shouldn't vary at all. The output is buffered before released so the tempo is mathematically equal to source. I'm guessing that the person experiencing this is playing MP3s ripped from vinyl or has a short/malfunction in their pitch slider. All of my tracks are bounced straight from the masters or control vinyl. I've never seen bpm flutter on a cdj. Any cdj.

    I understand the points about using MIDI to control tempo. Personally, I prefer the feel of a 1200 and like the sound of a scracth drop from a 12, more than a cue drop on a cdj. I use a midi controller for effects, but prefer the "old school" feel of a mixer & 12s. Just want the best of both worlds.

    An inherant problem with using analog 12s with a digital system is the wow & flutter of
    the deck. Traktor has addressed signal quality, control issues, etc. It just lacks the ability to lock the source tempo.
     
  8. DiscoNova

    DiscoNova NI Product Owner

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    You know - I, on the the other hand, haven't seen a single CDJ that doesn't fluctuate - at least occasionally. And since I see quite a number of them, I'm pretty sure I'm right on this one. During the last few months alone, I've been playing on at least ten different pairs of players ... pretty hard to swallow that all of them would have been broken.

    Shouldn't ... but does. Not actually the CD-player's fault, though. For example, the new 900/2000's have rather good DAC's ... while all the Pioneer's previous ones from entry level players to top-of-the-line 1000 mk3s were equipped with the same converter chips as far as I know. Unfortunately I so far have no personal experience on the new species, so I can't say whether they suffer from this.

    You need to remember that for a short while, the signal is analogue (between the player and Audio8). Therefore, there are two conversions; one D/A (in the player) and one A/D (in Audio8). Both of these run based on their own timing. Since the timings are not synchronized with each other, there is an occasional hitch. Since the samplings in both ends take place tens of thousands of times a second, the hitches in themself already cause a certain amount of fluctuation.
     
  9. scoobycarolan

    scoobycarolan NI Product Owner

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    Ok Disco. I'll agree on your last point and I won't get into a who plays on more cdjs argument with you either. Nobody will win. There may be a miniscule amount of wow & flutter in the cdj.

    All I was originally saying was it would be nice if Traktor could help smooth the much worse symptom on a 1200. This way we could spend more time working loops & effects than driving.
    ---
    Oh yeah, Telly. What your seeing is kind of what I'm talking about. If Traktor smoothed the bpm out on the source those values would be way more accurate & less arbitrary.
     
  10. DiscoNova

    DiscoNova NI Product Owner

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    I guess you missed my original point also; the problem you're having is more a psychological one than a real one. Even if the tracks are not "snap on synced", you don't actually need to correct it (though, because you can see that they are not exactly in sync, you want to make corrections ... as said, it's psychological).

    The way this could be "fixed" is to smooth out the display, not the speed detection. If you attempt to smooth the detection, as lethal_pizzle wrote, the application will actually need to disregard the position of the timecode signal or introduce an arbitrary amount of "delay" to buffer out the fluctuations. If, on the other hand, the displaying of values is smoothed, the psychological effect will vanish; out of sight, out of mind.
     
  11. TeLLy

    TeLLy NI Product Owner Extraordinaire

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    ^^I've been requesting this for a while. Maybe NI will now heed my pleas (and also send me a free Maschine).
     
  12. scoobycarolan

    scoobycarolan NI Product Owner

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    Wow. First you say I'm not as experienced as a DJ as you. Your comment about how many cdjs you use compared to me is condemnable as a case for this being untrue. Now you say I have psychological issues. Stay classy Disco.
     
  13. DiscoNova

    DiscoNova NI Product Owner

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    Just as an example, using a pair of CDJs does not mean using 14 distinct CDJs during a week when you have residency... nor do I count them as such.

    Well, as long as it's the truth... everyone does. Even I don't actually like it when I see that things are not in perfect sync. But I know that they don't need to be (just so we're clear; even knowing about it doesn't stop me from sometimes kicking a little more speed on the platter).
     
  14. Pixel 6

    Pixel 6 Forum Member

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    72
    The Technics 1200's have a frequency generating servo that helps minimize this. Based on a brushless DC motor, it uses a frequency reference (262.08 kHz, basically the key of C) to adjust for drag from the needle on the record.

    My 2 pennies

    - Pixel -
     
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