But if I'll do that I loos the benefit of the ASIO drivers. I understand that he is veru good.
Somthing else maybe?

I run Windows sounds through my onboard Realtek (set to default) and only use my interface for programs I allow. Disadvantage is this requires two speaker sets, but works well.

ASIO drivers are only as good as the programmer who wrote them. Not all will allow multiple programs to access the driver at the same time; and if they do, they need to be at the same sample rate/bit depth. That is another thing to check that Windows sound card settings match what SONAR has them "locked to." If they do not match, multiple programs will have issues accessing them at the same time. If they do match, the ASIO drivers may be limiting you, so WDM mode would be worth trying.

WDM mode is not "bad," per se, and if written properly should not be an issue with playback scenarios (due to potentially higher latency).

Well, I'm trying to change drivers to WDM mode and everything gets messy.
The software did test on my computer If this driver is appropriate for my computer and it is appropriate.
But any sound that I played from Sonar, came out with dirt.
Once again, and I can't hear any sound from any other source or software when the Sonar software is open.

frkfir
Well, I'm trying to change drivers to WDM mode and everything gets messy.
The software did test on my computer If this driver is appropriate for my computer and it is appropriate.
But any sound that I played from Sonar, came out with dirt.

 
Many interface drivers focus on ASIO and not so much on their WDM drivers, so your mileage may vary there. You can also try WASAPI driver mode. One thing you could try is increasing the number of samples on the Driver Settings tab in Edit->Preferences after you selecting either the WDM/KS or WASAPI driver modes. This will increase latency which may be a problem if you monitor your playing/singing through Sonar while recording, but if you're mostly concerned with mixing it's not an issue and may resolve the "dirt" issue.
 

frkfir
Once again, and I can't hear any sound from any other source or software when the Sonar software is open.

 
Just to reiterate another suggestion, make sure that the "Share Drivers With Other Programs" checkbox on the Playback and Recording tab in Edit->Preferences is checked.
 
Good luck!