I am using Sonar Artist.
I have armed a track for audio record  and am playing back several midi tracks
that I will record on the audio track.
The playback  and hence the recording  keeps changing speed, even though I have a constant tempo
set in the program.
I have set the recording master and playback master to be the soundcard   (Echo IO)
 
thanks for any info
Richard

Are you sure the project is not changing tempos (I.e., no data in the tempo map)?

If you launch a MIDI file with SONAR it will retain tempo from the MIDI file. If you import MIDI, it will not.

A tempo drift, sans actual tempo changes, can easily occur if you import a MIDI file.

no there is no data in the tempo map...
I created the midi information... its meant to be a constant tempo..
but it is drifting , slower and faster
 
 

Had to log onto a computer quick, typing on a phone is terrible.
 
Can you explain what you are doing in more detail? I am "assuming" based on your last post that you imported a song and are adding MIDI to it?
 
If so... only MIDI data will follow a tempo map, audio data does not, so in the above case you need to assign a tempo map to the underlying audio so that the beats line up with the timeline. Easiest method to do this is scoot the audio file right to align the first beat with the timeline, then place the now cursor on that first beat (snap to grid OFF), and hit Shift-M (Assign Measure/Beat at Now) and assign it exactly to the beat. You can then TAB to just transients (with the audio clip active) and continue to use Shift-M to create a tempo map that is accurate to your audio file. After that is completed, MIDI data will align correctly.
 
Audio data requires a tempo map to align MIDI data to. If that audio was not recorded to a click and is wandering tempo, the MIDI will drift in and out with it for timing.
 

ok.. I'll try to explain in more detail.
 
I first created some midi data.  In fact 4 tracks. I use that to play my multi timbral synth, playing the 4 tracks
via the external synth through a separate amp and speakers.  When I know that the midi data is good
I then want to record the 4 tracks back onto a 5th audio track in Sonar.
I add an audio track... set the record master  to the audio sound card .. connect the output of the synth
to the sound card input (Echo IOx)  and arm the audio track,
play/record  the 4 tracks  and the audio track records what is playing.
This has worked fine in the past... I have occasionally got the situation that I am getting now
that the tempo wobbles around.. sometimes getting slower and sometimes speeding up.
 
I can not remember how I fixed it in the past (hence the post :)  )
 

No worries. Thank you for the clarification. I have never used external gear, so hopefully others can chime in. If sending MIDI data only to an external synth and recording the audio back into SONAR, I would try disabling all plugins (E) first and turn off internal input echo on any soft synths. Is your MIDI clock set to internal? I wonder if you have it set to the keyboard which may not talk back well to SONAR.

OK... thanks for the suggestions.
I think the trick was to use  clock set to internal.
It was set to audio... When I set it to internal the problem has gone away
thanks again
Richard