echo when applying effects

I am trying to record my voice, via a mixer and microphone, accompanied by an imported .mpg. It seems to work fine, until I play it back and apply effects (compressor, equalization, normalize). Then it adds an echo to the stereo accompaniment track, even tho I didn’t select it. I tried selecting only the mono vocal track, when applying effects. The vocal track is grayed, and the stereo accompaniment tracks appear selected with clocks on the background. I’m new at this, and frustrated. How do I select only the vocal track to apply effects? And why does it add echo? Thanks. Tom in Texas

To get rid of the clocks see … Sync-Locked Track Groups - Audacity Manual

Ok…sorry I’m dense. So, if the clocks are in the background of the accompaniment tracks, does that mean the accompaniment tracks are selected, and subject to any effects I apply? I want to leave the accompaniment just as it is, and apply effects only to my voice, which is on a third mono track. Thanks. TnT

Please see this page in the manual.

Effects are applied to selected audio. The clocks (sync-locked track groups) are irrelevant. Make sure that you select only the track you want to apply the effect to.

– Bill

Try unchecking “Software playthrough of input” in Audacity preferences