another option..

turn OFF quantise to frames, line up your new synced track.
Group select video with the new track and the old audio track (if u wanna keep it)
Hit the G key

Voila, your audio track is now grouped with your video track
Turn on Quantise to frames and Trim the edges so as to align each frame. Vegas will shift the audio to the closes frame for you

Easy done

The trouble I have found with matching up to similar but not the same audio tracks is that the wave forms are like that too: similar but not exactly the same. So it does come down to sliding tracks back and forth.

Two things I do when attempting this type of operation:

1. turn off "quantize to frame" while you are doing the movement (gives you a finer level of adjustment)

2. For the purposes of matching, pan one track into the left channel, and the other track into the right. This makes it easier to distinguish if the tracks are in sync or not, and which one is early/late, etc. You can also adjust the volumes if you need to, like if you are sync'ing and live audio track with a CD track.

Ciao,

marks

P.S. Remember to turn "Quantize to Frames" back on, and to restore the proper pan settings.

If you're trying to sync two recordings of the one piece of audio, there's a much easier way.
Invert one track, adjust the volume in the track header so they're both the same. Then as you slide them around when you're in sync they cancel. As you approach sync you'll start to hear flanging. Piece of cake. If you don't have any AGC on either recording that is.

Except from what Kenny has said I don't think this is what he is trying to do. He is trying to replace one thing with a different thing, so all bets are off working this way. I've had exactly this problem recently with multiple takes of a pipe organ piece. Good luck finding matches in the waveforms and due to how suhc monster instruments work the delay from pressing the notes on the keyboard to when it should be heard are variable. Add the amount of sustain into the mix and what a headache. Danged if I can tell if it's in sync or not. And to further confound the problem organ music doesn't have much of a 'beat' so it's anything but metronome accurate.

So the musician sits down with me and watching the monitor says "there" and then listens to the other take and says "here" and wants me to line up "there" with "here" and in multiple places using velocity envelopes to correct his speed changes. We've almost got it right but man alive, being able to put markers inside an event would have made it ever so much easier.

Actually fudging the video by reshooting his hands on another keyboard and compositing that into the original vision would have been much easier. Keyboards all look the same.

Bob.

Bob.

there is a way to put markers ´"inside´" an event - it has to be done at project media level. Open a media clip in the trimmer - put a marker here. All events using that clip have markers "inside". And it even tells you the name of the marker if you select "show marker labels" in the view menu.

jacob.

Maybe I've been doing this wrong but this is my method.
Both the Video & Audio tracks are Grouped & locked together.
RightClick on the Audio Track First and UnCheck "Loop" (so the new audio doesn't loop itself).

I highlight the audio track I want to replace, Right-Click & select "Create Sub-Clip"
In the Project Media bin I now see a new media file called "xxxx.m2t - Sub Clip1"
Then I right click on this new created link in the Project Media bin & select "Replace".
Then navigate to my new audio file and select it. The new audio file then replaces the original audio track. The video & audio tracks are also still grouped and locked together.

After I do this I save the project using a different name to be able to revert back to the original.
If the new audio track is less in length than the video track or whole project it will be looped IF you have the loop switch on, that's why I uncheck the "loop" switch on the original audio track.