Tried using Jammr as a master clock to my DSI REV2 via USB and it was pretty erratic, like +/- 20 BPM.

I also experience problems with the midi clock. I have a Korg KROME EX, which I tell to take midi clock info over USB, jammr also sees my Korg fine, it also transmits the clock to it, bpm changes are well reflected in my Korg's sequencer, BUT if you stay on the same bpm for a longer period >1 minute, both the jammr's metronome clock and my Korg's get out of sync - still correct bpm but out of sync.

My idea was to program loops in the Korg to have a chord progression going all the time in the background while still being able to stick to jammr's metronome - this seems impossible.

Any ideas ?

cjacoby
I also experience problems with the midi clock. I have a Korg KROME EX, which I tell to take midi clock info over USB, jammr also sees my Korg fine, it also transmits the clock to it, bpm changes are well reflected in my Korg's sequencer, BUT if you stay on the same bpm for a longer period >1 minute, both the jammr's metronome clock and my Korg's get out of sync - still correct bpm but out of sync.My idea was to program loops in the Korg to have a chord progression going all the time in the background while still being able to stick to jammr's metronome - this seems impossible.Any ideas ?

I just set my master clock to be my REV2 and set the BPM and BPI the same as what I had going on. Obviously not clock-synced, but at least those entering the room would hear something rock solid to play along to.

I think it was successful: the other players seemed to be playing along on time.

But yeah, we need a stable clock. I think it's coming from their servers, so susceptible to network latency/jitter.

What we need is a distributed master/slave clock like Network Time Protocol so that drift/lag can be compensated by periodically syncing with master… and looks like some boffins have already proposed that:
https://www.nime.org/proceedings/2016/nime2016_paper0006.pdf

One thing I have found is that if you join an empty room at BPM 120 then i seem to get a lock. No drift. However once I change the BPM the midi clock getting sent to my drum machine does change and its synced for a couple of minutes then it starts to drift. I try to put a drum machine into a jam to keep people on track as no one appears to follow the metronome. But have found i spend more time disconnecting and reconnecting trying to hunt down the elusive sweet spot of soundcard settings and inputs.
Feels like witchcraft. The only thing i can think is its at the Jammr end as opposed to mine. As I have 3 midi devices that all stay locked together once they get the clock. Its the Jammr metronome that is actually drifiting. Which is fine when people just follow the metronome as everyone drifts together.
Kinda weird.

I don't think for a second it's your setup leeastone. Introducing a network into the mix just makes a few new problems to overcome.

It would also be sufficient if somehow a re-sync could be triggered after every interval … Somehow my sequencer only syncs after a bpm change.

leeastone
One thing I have found is that if you join an empty room at BPM 120 then i seem to get a lock. No drift. However once I change the BPM the midi clock getting sent to my drum machine does change and its synced for a couple of minutes then it starts to drift. I try to put a drum machine into a jam to keep people on track as no one appears to follow the metronome. But have found i spend more time disconnecting and reconnecting trying to hunt down the elusive sweet spot of soundcard settings and inputs. Feels like witchcraft. The only thing i can think is its at the Jammr end as opposed to mine. As I have 3 midi devices that all stay locked together once they get the clock. Its the Jammr metronome that is actually drifiting. Which is fine when people just follow the metronome as everyone drifts together.Kinda weird.

I'm going to play around with a clock/MIDI router VST and load that into the Jammr (which can operate as a VST host). Someone said that the Jammr “send clock to applications…” checkbox doesn't actually send out clock, but it does… kind of: I ran MidiOx to monitor my Mio output (which is what I selected in Jammr as my MIDI output) and it saw nothing.

Which was weird.

Somehow it is sending clock though.

It does initially pick up my Jammr clock, but flips out eventually. My REV2 has a BPM indicator (and has a really stable clock itself, so trust it) and it was picking up 96 BPM from Jammr (while Jammr was set to 95), but then it would periodically show 108 or 121 every ~20 seconds, flipping everything out.

I'm 100% dedicated to getting this to work. I'm even going to comb through the source code and see how it works.

I'll keep you guys posted on the MIDI clock/router/patchbay VST route too.

I'm finally connected and getting MIDI messages on tempo change, but it's not changing my tempo whatsoever. I'll keep hammering.

The Jammr app is running a metronome that doesn’t drift. Have the app divide that clock into 24 pulses per beat and send a MIDI clock (248) every pulse.

eb_liveDrums
The Jammr app is running a metronome that doesn’t drift. Have the app divide that clock into 24 pulses per beat and send a MIDI clock (248) every pulse.

Can you elaborate?