Hi guys bit of a noob question here, I've always just used stereo busses as thats what you insert in sonar, I was wondering does the interleave button change it to a mono buss and if so when would I use a mono buss.
Thanks

Yes the interleave button would turn a bus mono if that's what you need. You would do that if you wanted to set up mono effect return for instance. I do this for mono reverbs.

sausy1981
...when would I use a mono buss...

One example would be for parallel processing of a mono instrument (e.g. bass guitar, snare drum).

It just ensures it's mono at the end of the chain.
You can still insert stereo FX, but it converts the output to mono at the end.
You can have stereo input that will convert to mono at the end.
basically... that's it... it converts to mono at the end. If it's mono in and only mono fx, then it will be mono ... at the end.
 
:-)

...and its panpot becomes a true pan control instead of a balance control.

So For example, I like to have my vocal routed to a vocal bus.... My vocal track is mono and since it's the only track going to this bus then I presume that this buss should be mono? And it's ok to send/return the track to a stereo reverb? Thanks for the help guys.

It depends - are you just routing one vocal track to the vocal bus? If so, is there any particular reason? Usually when I set up a vocal bus it's because I want to process a number of vocal tracks together, ie vocal and backing, or two doubled vocal tracks. In those cases, I need a stereo bus because the different vocal tracks are panned across the stereo field. If you're just sending one mono vocal to a bus on it's own though, you don't really need the bus because you can do all the processing on the original track. Unless of course there's a reason to route one track to a bus that I'm not thinking of.

It's absolutely fine (and common practice) to send from a mono track to a stereo reverb bus though.

sharke
...Unless of course there's a reason to route one track to a bus that I'm not thinking of...

It can make things easier when you are exporting stems if each of the required stems can be represented by an individual bus.