I hope this title has caught your attention as I'm hoping to find someone who can help me figure out why this has been happening for the past year and longer. 
 
I'm running a RME UFX and its mixing software TotalMix. After working with a project, I inevitably create buses and send instruments, drums, vocs etc to them. I'll place a plug-in on the bus and sometimes it's okay - after holding my breath and turning my outputs down. Usually, continuing on in this fashion, I'll add one or 2/3  and I'll get this issue occurring. 
 
Sometimes I'll neglect to turn down the volume and I'll get this almighty loud distortion with the above image indicating some kind of audio 'blowout'. Sometimes it'll hint at it and it'll be okay and recover. Usually, Total FX stays like this and I'll get this low end clicking-like sound and no audio - CPU use not active as well. Sonar has not been completely killed though and I'm able to save the project, close it and re-open and it's all good again, until the next time. 
 
Today it occurred several times on buses - adding a WAVES plug-in, or a FabFilter...and it even happened once with a Cakewalk compressor...previously as I prefer to use the latter compressors/Eq's. Also today, I added the SoundRadix Surfer Eq on a track and presto, overload-city again. 
 
RME claims that it's not a driver issue as 'Neither Totalmix nor the driver interact with plugins or software internal busses'. So it can't be the problem right? I haven't talked to SR yet, but I have reached out to both WAVES and FF, both claiming no issues regarding this from their knowledge. So it goes around and around and I guess it comes back to something going on with Sonar in combination with these plug-ins but no-one seems to know what.
 
Anyone? - he asked one more time. 
 
Hope someone's got an idea. I'd send a support ticket but from what I've seen, I don't think I'd expect a response. On occasion, when Sonar has crashed, the 'send' to report never connects, so it's apparently a waste of time as well.
 
Thanks in advance.

Not sure if I can help (yet) ... but a couple of questions:

• Does the project have VSTis, which are not frozen yet? Does it happen in audio files only projects?
• Did you observe a certain combination of plugins in your project whenever this happens (e.g. one plug that is always there when it happens, even if not the last one added when the problem occurs)?
• Does it happen only/mostly at high CPU load? Only/mostly at low latency?
• Have you tried turning off the usual suspects (64bit engine, plug-in load balancing, ...)?

 
(I ask because I have seen weird issues that others have trouble reproducing when certain VSTs are involved, e.g. Kontakt/AD2 + FabFilter + Waves)

Hi Rob, thanks for the response.
 
Okay, I usually work on projects which are a combination of soft synth instruments and audio...only both and not either.
 
Usually occurs with compressor-type plugins...but can include eq's and other types...esp WAVES various. I've noticed it a lot with various WAVE compressors, and FabFilter Eq's, Dessers and multiband. As mentioned, the Sound Radix Surer Eq contributed to one but in a track. Their Drum Leveler in the past has caused issues. The only common thing...all VST 3's, although VST 2's have cause this as well...just that I typically use the 3's. 
 
CPU use is typically very low and spread evenly across my 8 cores, with one being the lowest. Depending upon the project and how much I've got going on there, mixing is usually down with a full buffer on my RME.
 
I have never turned off the 64bit engine...mostly because I have this innate psychological conditioning that 64bit is better. lol. I have run the load balancing once before but it actually made CPU usage worse and haven't touched it since.
 
Only Output's Substance has caused me pops and clicks in Kontact. No issues with AD2. 

I have the UFX as well and I have not seen this issue and everything is pretty stable but I do not have the plugins you mention. 
 
Which version of Sonar are you using?
 
Can you try to reproduce the problem with the included plugins in Sonar?
 
 

The symptom looks like some plugin is generating denormals due to an internal "crash" in the plugin. It can be hard to pin down such issues since it can occur randomly. When inserting plugins SONAR is streaming audio to them during this process so perhaps its a multithreading issue inside one of the plugins causing corrupted state.
If you can narrow it to which plugin causes it it would be easier to investigate potentially. Also check if turning off the audio engine before inserting the plugin avoids the problem.
PS: are you using sidechaining on the plugins in question?

karhide
I have the UFX as well and I have not seen this issue and everything is pretty stable but I do not have the plugins you mention. 
 
Which version of Sonar are you using?
 
Can you try to reproduce the problem with the included plugins in Sonar?
 
 

I'm using 2017.04 version. I don't normally work with Sonar's plug-ins except on the pro module. I did place the CA comp on a bus a while back and it caused this issue. 

Noel Borthwick [Cakewalk]
The symptom looks like some plugin is generating denormals due to an internal "crash" in the plugin. It can be hard to pin down such issues since it can occur randomly. When inserting plugins SONAR is streaming audio to them during this process so perhaps its a multithreading issue inside one of the plugins causing corrupted state.
If you can narrow it to which plugin causes it it would be easier to investigate potentially. Also check if turning off the audio engine before inserting the plugin avoids the problem.
PS: are you using sidechaining on the plugins in question?

Hi Noel. 
 
I do use side-chaining on the Pro-MB at times and have been experimenting with sending bass to the new WAVE'S F6 EQ but only on a rare occasion does it cause this issue...but the former has caused it on occasion. I have found though that doing the 'ctrl click drag' to copy a plugin on a bus will create this issue more often than not. 
 
I have had quite a few issues with FabFilter's Pro-MB. Placing it on say a drum bus has caused it. Placing it on say a submix bus, can trigger it.
 
Placing the FF's Pro-DS on a vocal bus will trigger it on occasion...typically if I add another down the chain it will more than likely trigger it. 
 
The FF's Pro-C2 compressor has caused this issue in the past but I don't use it as much as the Pro-MB. 
 
Adding WAVE's dbx 160 Compressor/limiter has caused this issue quite a lot. 
 
Their SSL range of EQ's and Comp, don't seem to cause this issue.
 
As mentioned above, I added SoundRadix's Surfer EQ on a track yesterday and it caused the issue, but on a track this time. 
 
I have had this issue occur in the past when placing Sonar's CA (no?) compressor on a bus.
 
Typically, if any of these plug-ins are loaded and saved on a project, then re-loading the project does not seem to trigger this issue. It happens when loading a new plug-in in that session...as mentioned, saving and re-loading allows me to continue without issue. So I guess a work-around. 
 
I do however find this very disruptive to my work flow. I have a go turning off the audio engine as suggested and see if that helps. 
 
Thanks
 
 
 
 

Try adding one plug in at a time until the problem occurs, however, that may not give a true indication of the problem as an accumulation of plugins may affect the single plugin that's causing the problem.

Jesse G
Try adding one plug in at a time until the problem occurs, however, that may not give a true indication of the problem as an accumulation of plugins may affect the single plugin that's causing the problem.

thanks. I have experienced just adding one plugin into a bus and it has triggered this reaction. Yes it can be triggered if there are several plugins but not necessarily. 

So you can repro this even in a project without other plugins? Weird.
I'll pass this on to QA and we'll try and reproduce it. Somehow I think its related to some routing combination in your project so if you can upload a very simple project that exhibits this we may have more luck reproducing it.