What I found today is, all I have to do is open Preferences, not even change a thing, and hit Apply and Close, and the sound degradation is gone.
So it is something which drifts out of its established control setting inside Sonar.
 
I went into \Preferences\Audio\Devices inside of Sonar and disabled unused Input Drivers:  And that did not stop the problem either
 
I also tried the "Reset MIDI and Audio" quick button on the header shortcut panel, no dice on that either.
 
TS

OK, no, the sound did it again.  I make a change and it sits dormant for 3 hours and I think I have it fixed, and then it starts again.
 

So I spoke with MOTU and the following applies to this sudden noise with the Analog ASIO drivers in Sonar.
 
1.  The MOTU unit with this set of drivers never did this with the old computer in Reaper
2.  The sound is not reproducible by using these ASIO drivers and inputs in stand alone Guitar Pro 5.2
 
So that tells me it is not the computer, nor the USB's (using the correct 2.0 USB), nor Windows 8.1, nor 828 Mk III, nor the ASIO drivers, nor Guitar Rig Pro 5.2.  They have all functioned fine independently.  The sound only crops up when I use all these things through Sonar X3c.
 
And given that I can stop the sound simply by opening the preferences and hitting the "apply" button...
 
 ....this tells me that Sonar X3c has an incompatibility issue with ASIO drivers, by initiating a periodic routine which corrupts them in the configuration setup, which is easily re-initiated by simply running preferences.
 
Not Solved, but I will highlight this problem to Cakewalk. 
 
TS

New MOTU drivers were released today, don't remember what it addresses though.
 

this tells me that Sonar X3c has an incompatibility issue with ASIO drivers, by initiating a periodic routine which corrupts them in the configuration setup, which is easily re-initiated by simply running preferences.
 
Not ALL hardware has this problem.  Neither my Roland Octa-Capture or my MAudio Fastrack Ultra 8R have this problem in X3c 64 bit - either in Windows 7 64 bit or Windows 8 64 bit.
 
 

fireberd
 Not ALL hardware has this problem.  Neither my Roland Octa-Capture or my MAudio Fastrack Ultra 8R have this problem in X3c 64 bit - either in Windows 7 64 bit or Windows 8 64 bit.

This is what makes this so hard to diagnose.  The 828 and ASIO drivers work fine through everything else, no scheduled event signal corruption.  It is only when I use Sonar when this happens.  And I stop the degradation with merely two Sonar menu clicks.  Since everything else functions fine on its own, and the degradation can be solved with a Sonar only action, this leads me still to thinking towards Sonar.
 
Nonetheless, I continue to pursue this with MOTU who is being very responsive and informative, usually interacting with me twice a day.  I made a copy of the sound and sent it to them - which very much sounds like a handshake sync request between two devices (not exactly but somewhat like the old 'dial up modem' sound).  My thought is that the drivers are dropping out and attempting a re-sync which is not happening until I hit Preferences-Apply in Sonar for some reason????
 
TS
 
 

Well I worked with the MOTU techs, and we were unable to produce a solution to the dropout of the Analog ASIO driven tracks.
 
So, I installed another DAW and have been monitoring its use of the same ASIO drivers and have two Analog tracks configured in exactly the same fashion as my Sonar X3c analog tracks and so far tonight no noise coming through this other DAW. 
 
I think this is a case of Sonar X3c dropping the integrity of the ASIO drivers, triggered by some event which happens every 10 minutes to 1 hour.  The MOTU works fine with Reaper DAW and direct to Dimension Pro, or Guitar Rig 5.2.
 
So I think this is Sonar unfortunately.
 

Not getting any response from Cakewalk Tech Support either on this.  I have filed two support requests and nothing, except confirmation of filing emails.
 
I have already had over 10 exchanges with MOTU in that same time.
 

OK, final resolution - I guess - or defacto resolution.  LOL!!
 
Today when I got back from a business trip, I switched on my studio and noticed that the MOTU 828 Mk III Hybrid control screen no longer worked and there were no sounds coming through ASIO driver driven functionality at all.  After a while I determined that the 828 was malfunctioning.
 
So, I went out and bought a PCI-e short slot Firewire 6 pin adapter and installed it into the Dell XPS 8700 - then hooked up my old MOTU 828 Mk III Firewire unit.  The sound is good, solid and stable now on that unit.
 
I will send the 828 Mk III Hybrid back into MOTU for repair.  Unfortunately, I bought this on eBay so I have no warrantee.  More and more I am figuring out, that if you buy an I/O on eBay used, it is often being sold for having a malfunction.  I am not sure a $100 discount off price is worth the risk of getting a malfunctioning or quirky interface.  Only new ones for me from now on.
 
Resolved, I guess.  At the very least I have my studio back.
 
TS

Good News!!  MOTU agreed to repair my new eBay purchased MOTU 828 Mk III under warranty.  I shipped it back in today.  In the meantime I am ordering a PCI-e dual processor (TI Chip) Firewire 800 card for the 828 Mk III Hybrid when it returns.  This will ensure that I have the fastest and most compatible interface duplex signal possible.
 
I love the MOTU support, and I love the 828 series, as I have been using it since 2001.  It is powerful, routing flexible and usually reliable.
 
Conclusions in this:

• Firewire 400 (6 pin) performs superior to USB 2.0 - both the duplex capability and the larger bandwidth make for a better overall experience with less problems interfacing to an I/O device.  I would recommend that users go to the expense of inserting a Firewire 400 (or 800) card into their machine over using resident USB 2.0 - as the performance is perceptively superior now that I have used both.  My interim rig, using a temporary Firewire 400 PCI-e card is actually performing much more stable and clear.

• The USB 2.0 drivers and the MOTU Hybrid did not seem to get along well.  My 828 mk III would lose driver sync when the PC screen saver kicked in, or at random times while working - it usually took an hour or two, but would always happen, forcing me to reboot my MOTU and my computer at least once with each use.
• Older or no-name resident Firewire 400 chipsets do not perform well with the MOTU 828 series.  I would replace an old resident Firewire 400 slot with a new PCI-e dual processor (TI chipset) insert board when interfacing to any Firewire devices.  Use Firewire 800 and step it down to a 6-pin via an adapter cable, or by having a dual standard card - if you can.

TS