How do you do this? I'm used to Audacity where you highlight a track and hit the "silence" button and that section of a track is silent. I only see "remove silence" in X studio. If I hit delete, it works but cuts the track in two. Must be a simple fix I bet?

Hey, M.  Do you know about creating an automated track mute envelope with the track header edit filter?  Works for both audio & midi tracks.  It's listed under 'Automating track and bus mute' in help file.
Best, HeyDan

Here's another option.

1. Position the Smart Tool in the top half of hte clip, and drag across the area where you want silence.
2. Go Process > Apply Effect > Gain. Turn all the Gain sliders to zero and click on OK.

Thanks guys It works a charm!

My preference is generally to split the audio clip and then just slip edit the start and end points. This is particularly good on vocal tracks, as it gives a nice visual representation of whats going on. I usually only split the audio at points where there is a significant gap - like in between each line of the verse or chorus, for example. Nothing wrong with the other options either. There are lots of ways to get things done in Sonar. The nice thing about slip editing is that it is non destructive. You can move the start and end points of the clip at any time if you want to, as all of the original audio is still accessible.

Another option that's real quick is select mute tool (F10 twice by default) and sweep select in the bottom half of the clip the section you want quiet. Reverse it by sweeping in the top half. F5 takes you back to the smart tool.

If you are doing that a lot in a session it gets even quicker because you only need to press and hold F10, sweep mute/unmute and then release F10 to get back where you were. It becomes an almost subconscious thing to do - like a lot of the 'new' methodology.

Mute tool