How best to combat fluctuating bpm from viny recordings?

I have read alot of generic posts regarding fluctuating bpm's from vinyl recordings but none that categorically state the best solution. Before I write anything else please let me state now :- yes I fully understand the differences between and know how to perform both normal and dynamic analysis of tracks.

I recently starting transferring my vinyl collection to files (currently using WAV) to add them to my rekordbox collection. However I'm finding that around half the recording have bpm fluctuations. These fluctuations are small (usually no more than 0.1 - 0.2 bpm). They ocurr at various and random times during tracks.

So if my understanding is corect I'm faced with two options.

1) Analyse these tracks 'normally' and adjust the beat grid manually at regular intervals to keep the bpm of the track overall constant but KNOW that the beat grid will be drifting out constantly (on certain tunes)

2) Analyse these track 'dynamically' and have rekordbox reading the new bpm each time it fluctuates.

My questions:

1) If I analyse everything in normal mode but KNOW that the bpm does actually shift during the track, will the cdj bpm reading not be wrong during the record at certain points?

2) If that is the case is it not better to dynamically analyse the tracks so that the bpm reading is more acurate throughout?

I guess what I'm fundamentally asking is: is 0.1-0.2 bpm enough of a fluctuation to warrant dynamic analysis?

If anyone has any direct experience with experimenting as to which method is best (bearing in mind the small level of fluctuation) I'd be very interested in hearing about it!

Glen Gavin August 07, 2013 22:33

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What is your turntable setup for ripping your vinyl collection?

Many years ago when I first switched from vinyl to digital music, I had the exact same problem when I loaded vinyl rips into Ableton Live. The tempo always fluctuated up and down slightly. It was a bitch to warp the tracks as a result.

One very important tip I have learned from experience: When recording vinyl to digital format, it is best to use the rubber mat that comes with your turntable instead of a DJ slipmat. The rubber mat prevents the vinyl record from slipping as the platter spins, which helps maintain a consistent tempo on the final recording.

I know that some people are going to cry out that the slip[mat makes no difference.... and in theory I would agree with them. But in experience, I have personally witnessed exactly the tempo fluctuation you mentioned. The rubber mat made a huge difference for me.

Now.... as for how to best fix your tracks that are already recorded and have the fluctuating tempo. One suggestion would be to use Ableton Live to warp those tracks to a constant tempo and then export to a new audio file. When you import the new audio file into Rekordbox, it will be much easier to match the grid.

John Kiser August 09, 2013 19:36 0 votes

Also.... you can adjust the beat grid in Rekordbox in sections to compensate for changing tempo. It will just take more work, but it is definitely possible. If the tempo change is small, then this works pretty well.

If the tempo changes often, then I'd stick with the Ableton Live warp and export process I mentioned above.

John Kiser August 09, 2013 19:41 0 votes

@ Fuse - That's very interesting about your experience with rubber slipmats - I will definitely use those from now on so thanks.

With regards to the fixing of the existing tracks. i've done a bit of fiddling around with it since I originally posted. I've found that despite the bpm fluctuations being only a few decimals, it's still better to dynamically analyse said tracks and then manually adjust the tracks at intervals. On some I get lucky and the metronome stays constant for large chunks of the tunes and I only need a couple of adjustments. Some are a nightmare and require beat grid adjustments and slight bpm changes every 16/32 beats. I still prefer to do it this way as the deck will at least register and show me any fluctuations as the changes can be faster AND slower so it's helpful to have a rough visual guide even though you'll treat those tunes like vinyl and expect to be touching the platter more often than a digital track.

I've never used Ableton so might look into that warping function. Is there a free/cheap version that will allow me to do taht without buying the whole program so I can experiment before buying the full????

Glen Gavin August 09, 2013 21:18 0 votes

There should be a free trial for Ableton Live, but if my memory serves correctly they will not allow file exports to be saved on the trial. If so, that would basically negate the very purpose you are seeking to accomplish.

John Kiser August 10, 2013 11:11 0 votes

Since this topic has been brought up, I thought I would share some general tips for best practices when it comes to recording vinyl to digital format:

1. Use a Direct Drive turntable with the rubber platter mat, and be sure to set the pitch lock to the Zero Tempo position.

2. If you have the option available, use a moving coil stylus. DJ styli are built for durability. Moving coils are built for accuracy.

3. Use a high quality Phono preamp if you have one available. DJ mixers are not always the best choice, unless you have a really high-end mixer. Most DJ mixers will color the sound to a degree. A few years ago I would use my home stereo preamp when recording vinyl to digital. Now I have a Xone DB4, so I just use that because of the simplicity since the sound card is built in.

4. I prefer to record into a professional audio editor software. I'm still using Peak Audio 7 for Mac, even though the company is now out of business. I like to record in 24 bit 48k because that is the spec of the Xone DB4 sound card. If you want to reduce file size, then you can use the software to dither down to 16 bit. I always keep my audio files in AIFF format.

John Kiser August 10, 2013 11:31 0 votes