Have you put a CC7 or CC1 event at the very beginning of your piece? That will set the modwheel so it is not zero. you need to put in the CC event, AND a value for it. Try 80-100. Do this for each inst.

Thanks for your attempts to help me. However, this is still absolutely doing my head in. I am now using Omnisphere, and I am still getting what seem to be randomized, unexplained drops in volume on playback. I say random because I can be playing back a section and sometimes the volume drops and sometimes it doesn't at exactly the same place in the timeline. 
 
In an effort to control this (and it wasn't what I wanted to do), I bounced the track to audio. And the same thing happens in the audio track. In my project I have "Zero Controllers When Play Stops" deselected. 
 
I don't understand how to insert CC events so that this does not occur (I think this is what I have to do) - can someone tell me click by click? I have tried searching. Also, please see my response to promidi's post above. 

Marshall
Thanks for your attempts to help me. However, this is still absolutely doing my head in. I am now using Omnisphere, and I am still getting what seem to be randomized, unexplained drops in volume on playback. I say random because I can be playing back a section and sometimes the volume drops and sometimes it doesn't at exactly the same place in the timeline. 
 
In an effort to control this (and it wasn't what I wanted to do), I bounced the track to audio. And the same thing happens in the audio track. In my project I have "Zero Controllers When Play Stops" deselected. 
 
I don't understand how to insert CC events so that this does not occur (I think this is what I have to do) - can someone tell me click by click? I have tried searching. Also, please see my response to promidi's post above. 

This might help: https://www.cakewalk.com/Documentation?product=SONAR&language=3&help=EditingMIDI.44.html
 
After you do it once or twice, it will make a lot more sense.
 
Regards,
Dan
 

To use Event List for CC events: Go to Event List. Hit "insert" on your (typing) keyboard. A box will come up. Choose type of event (it could be a note, text or, what you need, a CC event. Put in channel number, type of CC event (use CC1 or CC7 - volume). Next, add the Value for the CC event. This is a midi event, so it ranges from 0-127. That should it. Make sure you do it at the very start of the piece, so the modwheel will set permanently to that value. Then, use CC11 for on-the-fly adjustments.

michael diemer
To use Event List for CC events: Go to Event List. Hit "insert" on your (typing) keyboard. A box will come up. Choose type of event (it could be a note, text or, what you need, a CC event. Put in channel number, type of CC event (use CC1 or CC7 - volume). Next, add the Value for the CC event. This is a midi event, so it ranges from 0-127. That should it. Make sure you do it at the very start of the piece, so the modwheel will set permanently to that value. Then, use CC11 for on-the-fly adjustments.

Thanks - I must have a mental block - After I hit insert on my typing keyboard, under the "Kind" header I get the option of "Controller". I select that but there is no option to select CC1 or CC7, i.e., the type of CC event. 

Sorry Marshall, I was winging it: here's what to do: Go to Event List. Double click at the point in the music where you want to insert a controller event.  For example, to insert one at the start of the piece, double click on the first row. In the box that comes up, choose Controller from the list on the left. Hit "OK." In the column immediately to the right of the word "control," change the number to CC1 or CC7. There is some argument about which to use, but I have always used 7, and it works. Then, in the next column over, adjust the value. 80 is a good starting point, but you can always change it. Do the same process to put in CC11 events. You need to put one in immediately. The CC7 will set your modwheel in Aria and keep it there. You use CC11 after that for volume adjustments.
 
I've been using another DAW for awhile. I had to go back into Sonar (8.5) to refresh my memory!

Michael - thank you, I have got that.
 
So, if I am inputting midi data from my controller keyboard I have my right hand playing the notes and my left hand on the mod wheel. That works fine, so far so good.
 
However, if I let go of the mod wheel completely, then I find that the volume is so low I can hardly hear it when I am playing the notes, but on playback, the same notes are easily loud enough.
 
I often use MIDI Guitar II to input notes. So having my left hand on the mod wheel is not an option, and therefore the volume whilst inputting is too low. On playback however, the volume is much louder.
 
I tried inputting CC1 = 127 rather than 80, but whilst inputting, it is still not loud enough.  
 
How can I increase the volume on input so I can her it properly? 

Marshall
Michael - thank you, I have got that.
 
So, if I am inputting midi data from my controller keyboard I have my right hand playing the notes and my left hand on the mod wheel. That works fine, so far so good.
 
However, if I let go of the mod wheel completely, then I find that the volume is so low I can hardly hear it when I am playing the notes, but on playback, the same notes are easily loud enough.
 
I often use MIDI Guitar II to input notes. So having my left hand on the mod wheel is not an option, and therefore the volume whilst inputting is too low. On playback however, the volume is much louder.
 
I tried inputting CC1 = 127 rather than 80, but whilst inputting, it is still not loud enough.  
 
How can I increase the volume on input so I can her it properly? 

Gaffer tape on the mod wheel also works...
 
Dan

Yep, I can see that gaffer tape would be a solution! Any slightly more high tech suggestions would also be welcome 😀

Unforunately, my suggestion is only for midi. Can't help with audio as I don't do it, only midi!