Headphones as monitors
 

After recording drum tracks, I want to overdub a bass track.

When I am overdubbing and using headphones to monitor, I can hear the recorded drum tracks, but I don't hear the recording bass track through the headphones.

Can I make any adjustments so that you can hear both the recorded tracks and new recording track?

Re: Headphones as monitors
 

Don't know what your setup is, but could this be the culprit?