How to normalize split audio?

JackW wrote on 2/18/2009, 2:08 PM
Had a shoot the other day with two audio feeds (Channel 1, 2) to my PD-150.
Separated the inputs in Vegas by copying the audio track and using the "channel" function. I can normalize the left channel (input 1) which is fairly hot to begin with; no problem.

But when I try to normalize the right channel (input 2, on the second audio track) nothing happens -- normalizing has no effect. I'm not peaking anywhere -- far from it. The signal is very weak owing the the original mike placements.

Any idea what's going on here and whether it can be changed?

Jack

Comments

kentwolf wrote on 2/18/2009, 2:18 PM
Did you try to take it into Sound Forge and normalize it?

I personally never liked doing the normalization in Vegas...not sure why.

I have never seen Sound Forge not normalize something.
DavidMcKnight wrote on 2/18/2009, 2:56 PM
I've never seen Vegas not normalize anything either, though it only works on the peaks. I would suggest to look carefully at the wave form zoomed in, make sure you don't have a stray pop or click that is at peak. Cut out a small section from the track and see if you can normalize that. If you can, it's a sure bet that you have a peak somewhere else.
Jessariah67 wrote on 2/18/2009, 3:04 PM
If one channel is hot already, that would cause the other not to boost very much. I don't think Vegas does the channels independently. Try this: right click on the audio clip and switch to the lower channel only. Then try to normalize it.
TGS wrote on 2/18/2009, 3:06 PM
There may be one LOUD "spike" that is somewhere on that track that is keeping you from being able to normalize with a noticeable difference. If so, put a split around each side of the "spike" and then "un-normalize" and "re-normalize the sections on each side of the spike.
If the loud spike is right at the beginning of the video, as if you turned on a mixer and it made some kind of noise when turned on, put the split right after the Loud spike and normalize the rest.
Lastly, in case no change occurs no matter what, you can put a volume envelope on the weaker track and use your ears to bring it up to match the other channel.
jimingo wrote on 2/18/2009, 5:30 PM
Also, sometimes the spike can be so close to the beginning/end of the clip that you can't see it. Just trim a few frames on the beginnng and end and try normalizing again.
TorS wrote on 2/18/2009, 9:09 PM
These are two distinctly separate audio feeds, right, NOT a stereo recording? Otherwise I dont understand why you want to put them on separate tracks.

Anyway, don't normalize, compress. Use Graphic Dynamics or Wave Hammer (if you have it). Apply it to the whole track and move parts that need a different treatment to other tracks. Try different presets for (mild) compression and consider the results. Normalization just raises the over-all level, like twisting the volume button, while compression lowers the loud parts and raises the low. It will also apply gain to the result, giving you the raised level I think you want to get with normalization. The normal thing for audio in most kinds of video/DVD is to be compressed.

If it is spikes or the like that causes your problem, compression will take care of it.

Audio that has been recorded too low will have noise when you pull up the volume. Is that why you run two tracks - to reduce noise on the one? Run noise reduction and/or equalization first, before you compress (or normalize).
Tor
farss wrote on 2/18/2009, 11:15 PM
Realistically if audio has been recorded at a very low level compression will do nothing as the signal will be below the knee setting in all the presets. You can see if the compressor is doing anything by monitoring the "Reduction" meter in the default Track Compressor or the unlabelled meter in Wavehammer.

When using any FX but most importantly compression understanding the signal path Vegas uses is kind of important.

It's also important to note that compression is not the same as turning up the gain. Compression reduces the dynamics and hence increases the loudness. Heavily compressed speech and music sounds loud even turned down a long way. I have some uber compressed music for a current project that reads several dB over clip but it is not clipped but man does it sound LOUD, even turned down a long way. Oddly enough though it doesn't sound anything like most of the heavily compressed rock you'd normally hear. Some very clever work has been done on these tracks.

Bob.
JackW wrote on 2/19/2009, 10:33 AM
Thanks for all the input so far.

Here's a little more on the back story: Channel One (on the PD150) has input from a wireless mic on the presenter. Channel Two is coming from an audio mixer which is receiving input from two wireless shotguns which are picking up comments from a small audience. There is a great deal of background noise -- air conditioning, fan on the projector, etc., so the volume on the mixer was kept quite low. Too low!

Now I need to raise that channel at a few key moments to get comments from the participants. There is no spiking on this channel; I've look very carefully. Using noise reduction to get rid of the background won't be a problem. It's just that though Vegas doesn't recognize the channel it at all -- like the channel didn't exist.

I'll try compression and see if that has any effect, but I don't believe it will.

Addendum:

In looking at previous messages I think Jessariah may be onto the problem. I can't get at the computer at the moment, but I'm going to see what happens if I begin working with the low level channel (#2) first, then see about boosting volume on channel #1 using a volume envelope.

Again, thanks for everyone's help. I'll let you know the final result.

Jack