8pre cracking/popping noise help needed

[CTTE]

I'm having a problem that I am having difficulty resolving. Any troubleshooting suggestions would be appreciated. Sorry to ask for help on my first post, but I just found this forum and thought there might be some knowledgeable people here...

It is a new problem on a system that has worked flawlessly for months. A tiny, but consistent popping/crackling sound is present in the signal chain when attempting to record, or tracks are armed (it's not just in the headphone monitors, it actually records the clicks/pops). Had to cancel a session tonight and cancel two more this week when I could not resolve the problem.

I've heard sounds like this before when I ganged up multiple instances of reverb plug-ins on different tracks before I learned to use a bus, but I tested the system with a new R E A P E R project with just one track and no plug ins at all, and the problem was present.

I have moved everything in the system systematically out of the signal chain except the snake, and R E A P E R. The 8pres were individually tested, but both appeared to have the problem. There was a brief moment when one unit worked without the pops, making me think it was an 8pre or the ADAT connection problem, but we could not recreate that situation where we could get a clean channel after that.

The popping/crackling sounds make me think there might be a clock configuration problem with the MOTU 8pres. Or possibly this is something that can be fixed by reconfiguring R E A P E R? I did make one change to REAPER to use the ignore time block when copying and pasting tracks just before the problem surfaced, but that is the only system change.

Any suggestions on how I might logically troubleshoot this kit?

System configuration:

Windows 7 Home Premium
R E A P E R 4.14 x64 487639

StudioCat Project Studio DAW:
Intel i5 2400 @ 3.4GHz
· H67 motherboard
· SATA-III, TI Firewire, USB-3
· 4GB DDR3
· 250 & 500 GB HDs
· Intel HD 2000 video

Firewire Interface to:

MOTU 8pre #1 (tested in and out of signal chain)

ADAT optical to from MOTU #1 to:

MOTU 8pre #2 (tested in and out of signal chain)

API Lunchbox with 2 Daking 500 mic pres on ch 1 & 2 (tested in and out of signal chain)

Radial direct J48 on ch 3 (tested in and out of signal chain)

8pre converters to XLR to 16 ch snake

Swapped all cables between sound source and snake to no avail.

Not expecting miracles, but you guys may have seen something like this before. If so, please chime in!

Thanks!
Randy

[torrentg]

Hey,

Do you have a folder C:\Windows\Minidump with files in it?

If so, let me know and do not delete the files.

[CTTE]

Thanks, I am going to work on this in the morning and I'll let you know what I find. Thanks for the reply!

[CTTE]

I placed a call to Jim Roseberry at Purrfect Audio (614-565-8924) where I bought the system, and he instantly diagnosed the problem and assisted me with the fix, even though his hardware did not cause the problem.

In a nutshell, for those who care:
Although the two MOTU 8pre interfaces were connected via ADAT light cables properly, the control panel for the one I am using as a master clock and the one receiving ADAT output from the other unit into the input had the ADAT output port disabled which caused the second unit to default to using the internal clock. Since both units were using their own internal clocks the disparity caused the pops/clicks. When I opened the control panel and enabled both the master unit input and output channels, the second unit sync'd to the master unit's clock, eliminating the popping/clicking.

Simple hardware/config issue repaired in about 30 seconds if you knew where to look. Thanks to Jim and his continuing excellent customer service and standing behind the products he sells. It's continues to be a pleasure to do business with him.

If you are contemplating building your own system, but aren't completely sure you want to go that route, I can tell you that I am glad I spend a few extra bucks to get something reliable and to get access to someone who can bail you out in a pinch.

Thanks to everyone who replied...

Now back to work!

[torrentg]

Man (or woman, but I'm sure odds are that man heh) - very glad to hear your success. I wouldn't have been able to help you with that since I only have a single MOTU unit, The Traveler. Great how this contact of yours was able to hook you up proper. Thanks for telling us and good luck in the future. If you ever run into system (read: Windows) trouble, let us know and we should easily be able to sort it.

Paaaaeeeece, you're welcome.

[doubletriplezero]

Just created an account to say thanks for posting this solution 13 years later!

I've got a used motu 8pre which I am using in converter mode to provide additional inputs to my primary interface (focusrite scarlett 18i20).

Could not figure out where the small cracks and pops were coming from. Following the tips on this thread I set the sample rate clock on the focusrite to sync with the motu 8pre over adat and the noise is gone!

Thanks again if you're still out there!