I'm confident this most likely has to do with a sample rate issue, but I can't seem figure it out.  I know some probably think I'm crazy, but I do my tracking on my Alesis HD24 recorder (old school I know) then transfer the tracks and mix in the box.

I have a new song set up at 94 bpm and have programmed my drums using Superior Drummer 2.0.  I have tried several ways to get a scratch drum track onto a track of the Alesis HD24...so I can lay down my acoustic tracks without having to sync up Sonar every time...ie monitor the scratch drum track off the HD24 while recording guitars etc.

Now, I have everything sync'd using my Alesis BRC as the master generating SMPTE 30 fps non drop.  The BRC controls both the HD24 and Sonar (Sonar via a MOTU MTP USB interface).  Sonar SMPTE is also set up for 30 fps non drop.

This setup has always worked perfectly for me when using hardware synths including drums (using D4 drum modules).  My problem is...the software synth (Superior Drummer 2.0) track drifts out of sync the further into the song I get when I import my audio tracks into Sonar and play them back with the (live) Superior Drummer tracks.

I have tried recording the drum track in real time to the HD24 using the output of my sound card into the console, then bussed to a track on the HD24....all sync'd up via SMPTE....that doesn't work.

I have tried "exporting" the drum tracks into a mono track, then transferring that wav file to the HD24....that doesn't work.

I have tried exporting it NOT using fast bounce....no difference.

Everything is set up at 48K 24 bit, so I would think it all should play nice together...but it doesn't.  The further into the song it gets...the more it drifts out of sync.

The strange thing is....if I stop the song say at 1:00 into the song....then start it up again from there everything is in sync until it plays for a bit...usually very noticeable within 45 sec of playing.

I know I have other options...I could just record directly to Sonar (would probably need to get an audio interface with more ins and outs).  I could keep using my hardware synths (defeats the purpose of buying Superior Drummer, and having the vast selection of soft synths within Sonar).  Or I could just monitor the drums by syncing up Sonar every time I record an audio track.  This option is OK...but it bugs me as to why I can't get the sync issue figured out.

Just curious if you guys and gals might have any insight as to what would cause this.....?

Is the MOTU MTP in sync and set up at the same frame rate as well?

It all seems like a very round about way of creating a project. What is so important with the Alesis HD24 that you could not do in a DAW.

I would rebuild the system entirely around a DAW and do everything in that. You might be asking for trouble trying to sync things up as it is obvious you are having some issues. The good thing about only one system doing all the recording is that you should never have any sync issues and it seems like you inclined towards the virtual instruments anyway.

If you complete a project for example does this mean you have stuff in the HD24 and other stuff in your DAW. This is not a good situation. Keep your HD24 for recording live gigs. That is what is primarily designed to do or what it does really well. 

I just had a thought too. If you need multiple INS and OUTS is here any way  you can use the converters in the HD24 as a means of getting in and out of your DAW. eg ADATs are always live in that any input signals are automatically routed to the lightpipe OUT connection and anything received at the lightpipe IN connection is routed direct to the ADAT analogue outs. ie ADATs can be effectively used as an 8 IN / 8 OUT sound card.

Thanks for the tips guys.  I did check the setup program for the MOTU and it shows that it's the same 30 fps ND as the rest of my system.

I am leaning toward doing everything in the box.  It's just that my whole system has worked perfectly in sync for years....until I started trying to use soft synths.  That is where the issue comes into place.  I can sync up the BRC with the HD24 and Sonar, and record tracks from my hardware synths to the HD24, all sync'd to SMPTE...then transfer the files to the PC and everything is in perfect sync with everything else in Sonar.

To answer your question Jeff...once I have all my tracks recorded, I transfer them to my PC via a ViPower USB swap rack and HD24 Tools software.  So in other words...when my project is done, all my tracks are indeed in the PC and mixed in the box.  Nothing has to be sync'd then.

I'm just one of those guys who is not satisfied until I can figure out what is causing a problem.  I'll keep experimenting and see what I can come up with.  I know it has to be something relatively simple.

Thanks again guys...!

Just throwing another idea out.
In the sync page in sonar preferences, there is a tab for freewheel  or chase lock. Is that also set up?

Stone...I'll check that tomorrow when I get to the studio.  I would think it's set up for chase lock since it does actually sync.  The problem is...while it is syncing...it slowly drifts.  In other words....the soft synth drum track that I recorded to the HD24 is minutely faster than the actual synth track within Sonar.

After about a minute of playback, there is a very obvious "slapback" between the recorded drum track of the HD24 and the soft synth track in Sonar...that is with everything played back sync'd to SMPTE.

This is how I found the original problem to begin with.  I recorded the drum track to the HD24 so I could monitor that while laying down some acoustic guitar tracks.  After laying down 3 guitar tracks I transferred those tracks to the PC.  When the guitars were playing back with the Superior Drummer tracks within Sonar...they slowly started drifting out of sync.  After about a minute it was very obvious...they were about a half a second out of sync.

Like I said...it just bugs me to not know.  I will figure it out one way or another :) .

Wow. What a convoluted recording scheme...

Yes, it doesn't make sense and, like you, I hate not knowing also.
Drifting usually means not frame locked. What does clockworks report when you are in the middle of a sync lock? Is it 1/4 frame phase locked? What would happen if you used MTP as the master SMPTE clock?
What about using Sonar and the master, but slaved to the BRC with MMC for start and stop?

I had the same problem once until Irealised that my transferred wave files were net properly aligned. Zoom in tightly to the start of each audio file and see if it is exactly at the starting point. This means that you will have to zoom in and slowly scroll across the time line to make sure all of the music is at the proper starting point.

Peace

How well do both your HD24 and your PC audio interface generate 48K from SMPTE? If they don't both do that, you somehow need to get your sample clocks otherwise synced up so files recorded on the HD24 play back with exactly the same timing on the PC.