No sound from JACK?

Hi all,

Not really sure if this belongs here or under Ubuntu Studio, but as I'm not running U.S I thought I'd post here.

Basically, my problem is that no matter how hard I try, I just cannot get any sound through Jack. I've added myself to an audio group with the right permissions, I've even tried routing it to another soundcard, all to no avail :(

I can still route audio from application to application (ie, a drum loop from hydrogen to ardour), but I just can't hear anything.

One thing I have noticed though, is that even when Jack is running, I can still play music and videos through pulseaudio, if that has anything to do with it at all...

Any help would be greatly appreciated, and if you need any system info, just ask! :D