Audio Normalisation Help needed

[Sean Seah]

I have clips from 3 cam and one of them one only single channel, plus the gain was really low.

What is the best way to normalise all three? At the moment, I have a lot of overlaps from the multicam and the audio is going loud and soft like a roller coaster. IS there anyway I can pick everything and normalise at one go? I saw this function in FCP. I do knwo that Vegas has a normalise func but I dun know how best to use it

[John Cline]

The "Normalize" function in Vegas will adjust the peak level to a certain value. Unfortunately, peak levels are absolutely meaningless when it comes to determining how "loud" your final product is. The human ear doesn't determine loudness by the peak level, it determines it by the average (or RMS) level. The "normalize" function in Vegas (or FCP) is useless because it only makes adjustments based on peak levels and that simply will not match the levels of your three tracks.

You could use the Normalize function in Sound Forge, it can be set to normalize for average levels, which is what you want. Render out the audio from your three clips and pull it into Sound Forge. Use the Normalize function in Sound Forge and set it to normalize using "Average RMS power" and normalize to -20db and select "If clipping occurs apply Dymanic Compression." -20db is a good starting point, you will have to play with this value for your project. Once you have determined the appropriate RMS level, use that same value for everything and the loudness of the tracks will be matched throughout your entire project. Other audio editing software probably has something similar to average normailzation, but peak normalization will NOT get you the results you need.

John

[Sean Seah]

Ooh.. that is a little complexed for me. I'll have a go at it. Thanks!!

[James Harring]

I got this somewhere, can't really remember. I don't even know if accurate, but here's something that may help.

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How can Normalization, EQ, and Dynamic Compression help me master the audio in my project?

Answer
One suggestion to improve your mastering is to normalize while processing EQ or Dynamic Compression. All of our EQ and Compression (Dynamics) processes have a Gain slider. If you process a sample section of the loudest part of your file and see how much room you have left before reaching 0dB, you can use the Gain slider in that process to "normalize" at the same time.
Highlight what you know to be the loudest section or the area that contains the loudest peak. The easiest methods of finding the location of the highest peak in the file are:

Use Tools > Statistics, which will report Maximum sample position.
Use Tools > Find, and under Name choose "Find largest peak" (maximum value). That will drop the cursor at the position of the loudest peak.
Highlight a section to work on which contains this loudest peak. Have the Play meters visible so that you can monitor how much headroom you have before clipping when you generate Previews. When Previewing a Dynamics setting and the meters show -3.2 dB as the highest level, you can then raise Output Gain to +3.2 dB in the Dynamics dialog window, and it will effectively Normalize it by that amount at the same time the Dynamics processing is performed. After you have settled on parameters for Dynamics and your Preview shows 0.0 dB as the peak level (now that you have raised the Output Gain), click on the Selection button and under Selection choose "Select all data." Then when you click OK, it will process the entire file and not only the highlighted area you were using for your Preview. After you are done, you can go to Tools|Find, and under Name choose "Clipping" to see if levels went into the red anywhere.

It is a good idea to normalize at the same time you are processing EQ or Dynamic Compression because the fewer times you have to run any process, the better it will sound, and there will be less possibility of causing digital artifacts.

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How Do I: Normalizing audio tracks

Question
How do I make all my track volumes sound the same?

Answer
From the Process menu, choose Normalize to maximize the volume of a selection without clipping. The Normalize function scans the audio and applies a gain to raise its level to a specified (often very high) value.

The Normalize to value indicates the level to which the sound file is normalized. For example, when using peaks, if the peak level is -10 dB, and the Normalize to setting is set to -3 dB, a constant boost of 7 dB is applied to the entire file.

When using RMS levels, normalizing to 0 dB means boosting the signal so that it has the same apparent loudness as a 0 dB square wave, meaning incredibly loud. If you were to do so, all of the dynamic range of the signal would be squashed and all the peaks would either be clipped or seriously compressed. The lesson is this: normalizing a peak to 0 dB is okay, but normalizing RMS to anything above -6 dB is playing with fire.

When using Normalize on stereo data, if the selection includes both channels, normalization is computed on the loudest sample value found in either channel and the same gain is applied to both. If a single channel is selected in a stereo file, then Normalization affects only that channel.

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Dolby Digital AC-3 encodes are quiet

Question
When I encode audio using the Dolby Digital AC-3 encoder, the volume changes and the audio is quiet. Why is this?


Answer
If the audio that has been encoded in your AC-3 file is too quiet, you can make some adjustments in the Custom Templates window that should help with this.

If you are using the Dolby Digital AC-3 Pro encoder, you can customize the settings for your render. To do this, in the Render As dialog (or Save As in Sound Forge), choose Dolby Digital® AC-3 (*.ac3). To the right of the Template pull-down, you should see a Custom button, click on that to open the Custom template window.

In the Audio Service tab, change the Dialog Normalization to -31 dB.

Dialog normalization:Indicates how far, in decibels, the average dialog level of the encoded program is below digital 100%.The value of this parameter will directly affect the sound reproduction level when decoded.

Then, go to the Reprocessing tab. There you should see Dynamic Range Compression. For both choices under Dynamic range compression - Line mode profile, RF mode profile - choose None.

Line mode profile:Choose a setting to specify the type of compression that will be applied when the decoder is set to line mode and dynamic range control is applied.Dynamic range control limits the softest and the loudest portions of the audio stream to maintain a comfortable and intelligible listening level.RF overmodulation protection:Select this check box to apply an RF preemphasis filter is used in the clip-protection algorithm to prevent RF (antenna input) overmodulation in set-top-box decoders.

For technical specifications regarding the Dolby Digital® AC-3 encoder, please visit the Dolby Digital website.

[John Cline]

Once again, normalizing to peak values is useless when attempting to adjust for average loudness.