I'm really new to all this, so bear with me.  I have some audio loops of drums, they are just wave files.  I want to make them play at the speed of the song.  I click on Groove Clip Looping and it seems to fit perfectly into the measure, but now I get some kind of super fast echo.  There are no effects or anything else on.  I don't even have any other tracks.  Just the one audio track.  Doesn't seem to matter which drum loop I put in there, I get the same stuttering echo effect.  Any suggestions?
 
 

A couple questions to get the process started...
 
How many measures is the file?
How much of a tempo change are you trying to do?
Am I correct in assuming you're trying to slow down the tempo, not speed it up?

It's a one measure 4/4 electronic style drum loop.  Yes, I'm trying to slow it.  I think it's 130bpm (if I don't groove it and change the song tempo to 130, then it fits in the measure), I'm taking it to 120.

That's what I thought, it's harder to slow down than it is to speed up with decent fidelity. I figure 10% is max if you edit the slice points, but I can speed up like 160% no problem. I record loops at 100 BPM for this reason.
 
Here's a tutorial about looping based on Sonar 4, but loop editing hasn't changed much since then:
 
http://www.soundonsound.com/sos/sep05/articles/sonartech.htm
 
Pay special attention to the section on "Loop Construction Preparation" and "Tweaking the Slices."
 
Additional info along the same lines:
 
http://www.soundonsound.c...les/sonarnotes0302.asp
 
There's a way to get great fidelity when slowing down, but it takes some manual tweaking:
 
http://www.soundonsound.com/sos/sep11/articles/sonar-tech-0911.htm
 
If you won't be needing to change tempo any further, you can apply DSP stretching. Click on the right edge as if you're going to slip-edit it, but hold down the Control key. Now drag until the clip fits a measure at 120 BPM (you'll probably want snap on for this). The sound quality will be sketchy because it's in Preview mode. Bounce the clip to itself to improve the sound quality.
 
There's more to stretching, but these are the basics and should get you started.

Any luck with using these suggestions?