VSTi MIDI timing inaccuracy when looping portions of a track

I've seen other threads stating the same thing your talking about. I've always had fairly descent results looping in Sonar. But I really think its the nature of computer recording to have all these sorts of problems never ending. Dedicated systems built with a specific intention never seem to have these problems. For instance the Korg M3 sequencer works 99.9% of the time and midi in general seems much tighter not dropping notes and timing seems much tighter etc. Anyways, and I don't mean to get off topic, just mentioning my observations. Computer interfaces are great. But with all the advantages offered by computer recording, it seems we put up with so many problems. It's seems to be the nature of it.

CRX... what sound card are you using and what driver mode?
 
Factory cards can do this. It tends to show up more when working with MIDI based stuff using softsynths. Factory cards can generally handle the audio stuff pretty well.... aka: using it as a tape recorder..... but the load placed on the sound card chips to process the softsynths in real time is often too much.
 
If this is the problem, a dedicated USB interface running ASIO will generally solve the issue.....
 
Check your midi settings..... latency, and buffers first though..... you can generally adjust them a bit to get improved performance to a certain point.  The best solution though is a dedicated interface.

Cheers, I'll try those tips. It's a Motu828 mk3 firewire card using the ASIO drivers and it's normally well behaved (has glitched out on me once or twice requiring me to quit SONAR and turn the card off and on again but for the most part has been a very good card).
 
I'd like to get MIDI sorted for softsynths, for my external gear I still mostly use my Atari (15 years solid use and still rock solid). When it's not looping the MIDI jitter in SONAR is pretty good compared to other DAWs (ahem cough Live is crap). If I could just get a bit more fluid in the PRV and sort the loop problem perhaps I'd go all in.

Try look if sonar make correct loop range. Sometimes if i select area for loop, it dont select properly and selection is not accurate. This make timing inaccuracy when looping. Solution is look closer to loop points and set it correct manually. Maybe help.

The loop boundaries are set to bar lines, no MIDI FX and it's the 64 bit version of the plug. What I mean by the timing slowly 'degenerates is' is the different channels (I have kick and snare on one, hats on another) seem to drift out of time with each other. It happens after the first loop and and gets steadily worse.

simpleman
You are using the drum machine 'D16 Nepheton'?
Is Sonar loosing sync with this external device. I will presume so, if that's the case.

I gather you Googled it and got fooled by that mock image of a hardware device.  D16 Group is a software company, and the Nepheton is strictly a plug-in.
 
Getting back to the issue, my considered opinion is... I dunno.   I can't say I've ever heard SONAR users complain of MIDI tracks sent to the same synth going out of sync with each other. Previous reports of looping issues have always been about soft synths going out of sync with audio tracks and the audio metronome or possibly with another soft synth.
 
Again, I would ask whether you can reproduce the issue with another drum synth. If not, I'd suggest you hit up the D-16 forum.
 
 
 
 

Definitely try the metronome thing. MIDI timing drift when looping is a known issue and someone from Cake told us about this workaround ages ago. I use it and have never experienced the problem since.

I was using 44.1 and the metronome tip seemed to fix it. So weird.