How do I monitor, say delay or reverb in an audio track in Vegas or Acid for that matter, without recording/printing it to the track? Monitor only and add later.
Not sure I follow you, but when you add any effect to a track or bus it is always part of the mix in realtime. There is no need to "print" it before you hear it.
I guess what I am trying to say is: In real time, how do I monitor say reverb on a vocal track while recording it? I know how to monitor while mixing.. Second, I don't want to print the reverb on that track (it is only for the vocalist) as I will add a reverb at a later time when mixing?
Yes it is entirely possible. You didn't say which version of Vegas, so I'll describe VP10....
From View Menu, select "Mixing Console".
Arm (record Ready) a track; right click Arm button and select "Input" = Input Monitoring Auto. This will allow monitoring of Input before you press Record, and you will hear the recorded material when you press Play after recording.
At top of Mixing Console select "Insert Assignable FX" then select a desired Reverb from the suggested FX.
You'll now find a dedicated FX channel containing that Reverb inserted into the mixer - you can Send to that from a small fader in your Armed channel, as well as all other channels (may have to select "Sends" in the mixer left side selection panel to make the Send visible in the channel).