100% Panning Issue

do you have the monitor hooked up directly to the output of the RME or does it got through a mixer first?

make sure and check your offset mode to see if that track has inadvertently been set to some value of panning in offset.

Are their any plug-ins in the signal path which may introduce crosstalk?

verify your panning laws are still at the default.

I'm not sure then.  I'm certain this does not happen to me, especially on every project.  unless someone else has some suggestions, you might want to call tech support.

It would be difficult to be certain unless you performed the test I described, or something similar.  I never noticed until I was creating backing tracks for live situations, panning the click hard left and the synth hard right.  In the mastering stage for those, looking at the stereo tracks during the count-in, you can't even see any waveforms in the right channel fully zoomed, but that doesn't seem to matter.  I only noticed originally because I could hear the count-ins with my PA (right channel only) cranked, something I obviously don't want the audience to hear.
 
I guess what I'm saying is you probably would never notice unless you were doing very particular things.

Just dug out my Firestudio Project and the issue is no longer present.  So it does appear to be something with the RME, despite a full software reset.  Sorry SONAR, you're cool on this one.  Thanks for the responses.

I have a Babyface so I'll check this tonight. Does it happen in headphones as well or just the monitors?

Also worth checking with a standalone synth to confirm 100% that Sonar isn't involved.

take a look at the pic below...  the middle section, software playback is where i'd look first.  click the little wrench on the output channels then the two knobs to the right are width and fx send.  set with all the way up and send all the way down.  the bottom section is hardware outs. same thing here set fx return negative infinity.  then the control room panel bottom center-right you can click the mute fx button. 
or, you could bring up the output fx window and turn off reverb and delay. 
the interface has a ton of options!  been checking out the rme stuff for a future upgrade.  
how do you like the babyface?
 

I just tried this with my Babyface and I do indeed hear a little signal coming from one speaker when the track is panned 100% to the other. It's very faint and I can only hear it when the other monitor is turned off but it's definitely there. However - and I don't know what to make of this - if I play music through, say, Windows Media Player and use the RME's Total Mix interface to pan the signal 100% to one side, I DON'T hear any traces of the other channel in the silent speaker. Not even when I crank the volume right up. On my software playback channel, I have the width set at 1.00 and the FX send is totally off. The FX send on my main is also all the way down. 
 
It would be interesting to know if you can reproduce this problem in other DAW's. Right now I only have Sonar installed. 

scook

darkcatalyst
 Xonar X3 build 239

I just noticed this. If this is X3 Producer, build 239 was X3c, update to X3e http://www.cakewalk.com/Support/Knowledge-Base/2007013361/SONAR-X3e-Update If it is not Producer make sure the about screen shows X3e for whatever version it is.
 

I'm running X3e and it definitely happens there. 

konradh
Maybe I'm dumb, but wouldn't this be more likely to be an issue with the sound card or interface?

Not at all dumb. Haven't measured crosstalk on every interface in the world, but -55 to -60 dB is not uncommon at both higher and lower frequencies. Crosstalk also varies with levels. It can also happen outside the interface, e.g., cables being close to each other.

@swamptooth thanks for the details - no luck after adjusting all those settings.  I like the Babyface a lot, it's definitely a step up from the Firestudio Project.
 
After a bit more testing, to summarize my issue: 
 
With the RME, I can hear the bleed during playback.  Bleed is also present in mixes.  With the Firestudio, I can't hear the bleed during playback, but still hear it after mixdown.  I had been experimenting purely with output pan, but input pan doesn't seem to make a difference.
 
I entertained the idea that the crosstalk is introduced by the device I'm playing the exported tracks out of.  I've tried with my PC soundcard, my Nexus 5, and a separate laptop - crosstalk happens across all three.  Tried a variety of headphones and speakers, no change.  But the main reason I think it's not the device later in the chain is that I'm able to hear the bleed during playback with the RME in SONAR.
 
Maybe a dumb question, but the mixdown process is purely algorithmic, correct?  So no hardware should have any bearing on what happens during the export itself (other than the CPU).  Just trying to figure out any further avenue to test/explore this issue.

Pretty legit question considering the oddity - no change from center, still slightly audible in the right speaker.  Perhaps somewhat interestingly, panning the master hard right actually eliminates the sound, though that also makes sense in a way.