How to adjust audio level when video is split

Raptor88 wrote on 11/18/2017, 4:12 PM

I have a video that I plan to post on youtube, of my portable generator running while I assemble a sound reduction box that I built around it. The purpose is to show the amount of sound reduction from the bare generator to the generator enclosed in the quiet box.

To speed up portions of the video so the viewer does not have to watch the whole process in real-time, I split the video in several places. This allows dragging the right end of a clip to the left to speed up that clip.

Now I want to add another audio track to do some narration. I want to lower the level of the generator sound while I'm talking. Say I start a narration in a normal speed clip, continue through the fast speed clip, continue through the next normal speed clip, continue through a fast speed clip and end that narration in a normal speed clip. Like this:

|---1norm speed *v---|==2fast speed==|---3norm speed---|==4fast speed==|---*^5norm speed ......

The *v is where the generator audio track level is lowered and the *^ is where it is raised back to normal level.

Is the only way to do this to:
- ramp the gen audio down in clip1
- lower the level in clip2 to match clip1
- lower the level in clip3 to match
- lower the level in clip4 to match
- ramp the level back to normal in clip5?

Any easier way? Takes more time to ask here than to do it but I want to learn a new technique for future use if one is available that's better then the above procedure.

Thanks.

 

Comments

Musicvid wrote on 11/18/2017, 4:51 PM

Vegas doesn't auto-duck audio, unfortunately.

Vegas Pro probably still has the ability to ride gains on a virtual mixer.

cris wrote on 11/19/2017, 11:55 AM

You can do this quite simply with a gate set in ducking mode and whose side chain is fed by the narration audio track. A "gate" is a device that reduces the level of an audio track when an incoming signal goes _below_ a certain threshold. The incoming signal can be the track itself (useful for example for removing noise, whose level hopefully is always below the interesting signal); or it can be another signal (said to be fed by the "side chain", since hardware gates often have a physical input on the side to feed this other signal). When you put a gate in ducking mode, it lowers the track when the level of the incoming signal is _over_ the certain threshold.

So if you have a track on your music signal and use the narration as side signal, set the threshold so that it's below the narration level, and set the reduction to 3-4dB, the net effect is that your music will be lowered of 3-4dB when the narration track is not silent.

There's hardware gates of course, but for since MS supports VSTs, you may be able find free VSTs which do the job. What you need to check is that they have a ducking mode, and support side-chain (the simples types, which don't do that, work perfectly for noise reduction but not for your goals).

Unfortunately I use commercial products (in gate case, the stock Sonitus Gate coming with Sonar is perfect for the job) so I don't know of free options, but google is your friend..

 

Raptor88 wrote on 11/19/2017, 2:29 PM

Vegas doesn't auto-duck audio, unfortunately.

Vegas Pro probably still has the ability to ride gains on a virtual mixer.

Didn't know what auto-duck meant but Chris explained it before I had to Google it.

Thanks.

Raptor88 wrote on 11/19/2017, 2:30 PM

You can do this quite simply with a gate set in ducking mode and whose side chain is fed by the narration audio track. A "gate" is a device that reduces the level of an audio track when an incoming signal goes _below_ a certain threshold. The incoming signal can be the track itself (useful for example for removing noise, whose level hopefully is always below the interesting signal); or it can be another signal (said to be fed by the "side chain", since hardware gates often have a physical input on the side to feed this other signal). When you put a gate in ducking mode, it lowers the track when the level of the incoming signal is _over_ the certain threshold.

So if you have a track on your music signal and use the narration as side signal, set the threshold so that it's below the narration level, and set the reduction to 3-4dB, the net effect is that your music will be lowered of 3-4dB when the narration track is not silent.

There's hardware gates of course, but for since MS supports VSTs, you may be able find free VSTs which do the job. What you need to check is that they have a ducking mode, and support side-chain (the simples types, which don't do that, work perfectly for noise reduction but not for your goals).

Unfortunately I use commercial products (in gate case, the stock Sonitus Gate coming with Sonar is perfect for the job) so I don't know of free options, but google is your friend..

 


Nice explanation. I'll be doing some Googling to learn more about this technique.

Thanks.