Problem With Midi Sync When Changing Bpm

hi, I’m trying to MIDI sync Renoise with other applications, but I have faced with a strange issue when trying to change BPM: the BPM change happens instantly on the MIDI master, but happens progressively on the MIDI slave: suppose you have to go from 60 to 120BPM, this is what happens:

# master slave  
00 60 60  
01 120 60 <= here the master tells the slave that the change happened  
02 120 80   
03 120 100   
04 120 110  
05 120 115  
06 120 118  
07 120 119  
08 120 120  

what am I doing wrong? this happens in all scenarios: when synching two instances of Renoise, an instance of Renoise with an instance of another program, both on the same PC or on different PC’s. When operating on a single PC, MIDI Yoke is used, otherwise my M-Audio Delta 2496 MIDI port is used.

is it really this like MIDI synch works?

Yes, unfortunately. Renoise progresses to new BPMs, to compensate MIDI timing jitter. MIDI clock timing is quite worse in general, so if we would instantly jump to new tempi, the BPM would jump around all the time in Renoise.
Theres an option to control this smoothing, progress though → Preferences → MIDI → MIDI Clock Slave → Smoothing

argh, then I’m f***ed… so is Rewire the only alternative? could Rewire be used between two PC’s in some way?

What are you trying to achieve?
What applications are you trying to sync?

There are applications for using vst/vstis over lan if that helps…

on my PC there are Renoise and Plogue Bidule, on my mate’s Mac there is Ableton Live.

the thing I was trying to achieve is a jump from 64BPM to 128BPM in a song which gets played by Renoise and Live. when we tried it yesterday night, we encountered this problem, and then noticed that the problem was more general.

I actually hope that my mate will get rid of Live and use something more capable of doing music rather than just turning knobs and triggering loops (he is a very talented guitarist, after all), so we could have a more VST-based approach and your tip would be helpful then.

I see…

Perhaps a vst that send midi clock data could help you then.