[Solved] sync not working as expected when dealing with doubled bmp

@Max > Can you clarify how / when / where you doubled it? Was the track playing and you edited the grid?

Gladly.

 I edited it in performance mode on the deck with the controls on the skin, and then reloaded the song.

 Your question caused me to test this on a second PC with it's own library.  I edited the song in export mode last night but never tested it on that PC/library.  After reading your question I fired up the second PC, switched to performance mode without a controller, loaded the songs, set the master deck, hit sync on the other track and it worked properly.

I then fired up the first PC and tested again.  I have the problem with that PC still.  On that PC I am using a DDJ-RX, although I don't think that is relevant to the issue.

I will try moving the tracks from the working PC to the other to see if a export edited makes a difference than a performance edited.

@Max > Okay, so allow me to clarify...

- the track was loaded, but it was 71.8BPM
- using the DDJ-RX, you adjusted the grid with the 2X button to double it to 143.6BPM, then reloaded the track
- you tried to sync another track (original BPM of 95) but it jumped to 71.8 instead of 143.6

Where I'm a bit confused is you say that this is the first track -- were you not playing anything else at the time?

I just tried this using a track measured at 60bpm (which was wrong, it was supposed to be 120). I loaded a 170BPM track, and it matched the 60BPM at 120. When I doubled the 60 to 120, the other track immediately jumped to show 240 (it was paused), but when I hit play, it matched back at 120.

As far as I'm concerned, the doubling matching seems to be working, but I might ask that you check your setting in the Preferences > Controller > Deck:

First, thank you for your time trying to sort this out.  I appreciate it.

I verified that "Allow Beat Sync with double/half BPM" was checked.   I have not moved the tracks from the working PC to the non-working one.  I did try without the controller on the non-working one with no difference.

I have made a video of what I am experiencing.  The forum doesn't seem to like video uploads so I am putting it on youtube and will add the link.

https://youtu.be/BxIlZNUeQMI 

I think it's all about the math...

143.60 is 32.31% from 190BPM, but it's -33.84% to get to 95BPM.

The lower difference is to double it rather than halve it, so it automatically jumps to 190.

Okay, I verified that it is the "Allow Beat Sync with double/half BPM" that caused the issue.  My second PC did not have this checked... I removed the check on the first PC and sync now worked as expected. 

That raises a different issue.  I believe that if I leave that checked, and put Cupid Shuffle back at it's 71,8 bpm, then the sync would work as expected.  However, I would think the effects would not react to that track the way I would like.  To me that song sounds more like 143.6....   But, if I leave the BPM set doubled on Cupid, then other songs would not sync doubled/half with the check box unselected.

I wish there was an option to specify for the odd track that doesn't fit into the norm.

If your curious about the end goal, this is to make a transition setup faster.  Here is a link to a practice video that a manually set up the beginning of it.  As a mobile DJ I have frequent interruptions and such during my mixing.  So, while I am able to beatmatch, etc., the faster I can be set up for a busy transition, the better.

https://youtu.be/Dbbp09twmAs 

@Max > If you had Cupid Shuffle at 71.8BPM, to get to 95BPM is still a difference of 32.31%. It doesn't matter what the grid is, it's how it's going to affect the speed of the track.

I'm a mobile DJ myself and understand the benefits of being able to "GTD!" ;)

So, I experimented a little... I selected the Allow doubled/half again.  I loaded and started playing the 95bpm track.  Then I picked several songs with the 71.8bpm.

All of the songs I picked went to 95 when I hit sync.

Maybe I'm not understanding what you meant in your last response.

Okay, so you beat-gridded the track to be at 71.8 instead of 143.6; when it matched the track playing at 95BPM, it was increased by +32.31% in either case. The end result of case 1 was that it was at 190BPM, but case 2 was 95BPM.

It really doesn't matter either way, because if you wanted to mix a track at 100BPM, it would match by decreasing 5% to match the 95BPMs as a natrual tempo, or as half of 190.

I get the logic behind it.  It's picking the closest or smallest percentage change.

I wonder if it would be possible to add the ability  to specify an allowable BPM sync range in the track information.

Maybe, the more I think about it, I'm trying to solve a problem that doesn't really have an impact.  My thinking was on beat matching the effects there could still be an issue.  But, I can change the parameter for the effect to double or half the beat.

Thank you for taking the time to explain the logic of why it was doing it.

No worries. I come across tracks all the time which are BPM'd incorrectly (either 1/2 or 2x), and with the new setting to match those half or double tempo tracks, I'm less worried about the sync and more cheezed that I had to go find the track at the wrong end of the BPM scale!