sound level across multiple files

[serendipity]

I am recording audio books, so I have many different, but connected, files - one for each chapter. Is there any way to set a baseline volume so that I can easily conform each chapter to it?

As it stands, sometimes I come up with one chapter at one volume and the next much louder or quieter - not because I recorded it under different circumstances or anything, just because perhaps one chapter had some loud speaking and excitement, and then when it was normalized, it set a higher threshold.

It's very hard to do this either by eyeball or "earball" methods. I'm hoping there's a simple answer?

Thanx!

[alatham]

You have two options:
1) Compress the hell out of it. This will get the volume levels about the same, but the audio quality will suffer, especially if it was recorded well.
Try Compressor settings like these to start:
Threshold = -18dB
Ratio = 5:1
Attack time = as quick as possible

2) Careful listening and use of the envelope tool. Using headphones will help to remove the influence of speaker position from the perceived volume level. This will take much more time but will sound better in the end.

[serendipity]

OK, that gives me a place to start...
[I have no idea what any of those things are - but at least now I know where to look.]

Thanx!

[alatham]

The Compressor is found at effects -> Compressor.

The Envelope tool is highly useful:
http://www.audacityteam.org/manual/inde ... ls_Toolbar

There's a whole separate page on how to use it here:
http://www.audacityteam.org/manual/inde ... elope_Tool

[serendipity]

I will take a look - Thanx much!
--Julie

[steve]

There's a LADSPA plugin called SC4 (Studio Compressor 4?) which is a bit more complex than the standard Audacity compressor, but a lot better. Once you've got the hang of the built in one (which is easier to use) you might like to try the SC4.

[comcon]

Also --

Don't normalize, until all chapters are ready to go, and then normalize all tracks at once equally.

You can either use different software that can normalize multiple files to the one with the least headroom (dbPowerAmp for one) or in Audacity import all tracks and equalize at once.

This with moderate compression should give you good results without loosing the dynamics you're looking for.

[kozikowski]

Is everybody ignoring the "Normalize" tool for a reason? Select one chapter in the book and apply the Effect > Normalize. It will push the loudest peak in the chapter to -3. Select the next chapter. Apply Normalize. Etc. You can't select the whole book. It has to be chapters.

This filter has the advantage of not having adjustments at all and it doesn't change the character or the personality of the performer. Unless your did some very extraordinarily messy things with the microphone during a performance, then all the chapters should come out approximately the same level--or good to do with. This fails if you dropped the mic in the middle of a chapter, hit it with a pencil, or sneezed. That chapter you must do manually.

The problem with the various compressors is that they're a religion. Compressors can have, at minimum, four different sliders. Attack, Release, Threshold, and Compression Ratio. Some compressors have a lot more. Different people will swear that their settings are the One True Path even though we know that compression technology changes with the type of performance. Another problem with compressors is they make the background room noise go up and down. They "pump." Can I assume you're not recording in a studio?

They're something of a violin. In the right hands, they can certainly do magic things. But I'm no Perlman and you probably aren't either. Many compressors come with settings already applied and one of them may do what you want.

So another opinion heard from.

Koz

[alatham]

But I'm no Perlman and you probably aren't either.

I know there's a Yo Yo mama joke here somewhere, but I can't quite bow it.

Seriously though, you can apply normalize to many tracks at once. It will analyze each track separately and adjust each individual track to make them all peak at -3dB. This is the difference between Amplify and Normalize. If you do the same thing with Amplify it will analyze all the files and apply the same gain setting to each track so only one will actually peak at whatever level you choose.

[steve]

Is everybody ignoring the "Normalize" tool for a reason?

I ignore the "Normalize" tool in Audacity 1.2.6 because it is so limited compared to the "Amplify" effect. The only thing it has going for it is the ability to remove DC offset.