How do you "amplify" using GarageBand?

DSayers · Post by **DSayers** » April 10th, 2015, 7:39 am

I've finished and had proofed Daniel Defoe's The Storm. My MC discovered that all but one of the files is between 84 and 86 (decibels, I'm guessing. The files need to be amplified to 87.

I've never done this with GarageBand. Does anyone know where I would begin? Thanks.

-denny

tovarisch · Post by **tovarisch** » April 10th, 2015, 7:53 am

Reading about amplification in the GarageBand forum I see folks actually suggesting using Audacity for post-processing. Have you thought about it? Audacity is quite friendly. You don't have to use it for recording (although many on LV do), of course, if GB is easier for you, but only on rare occasions when you need things like amplification, notch filtering, noise reduction, etc.

Also, I saw folks talking of plug-ins for GB. Visit its forum, there are tons of useful advice, I am sure of it.

Post by **Availle** » April 10th, 2015, 7:59 am

Our optimal loudness target is 89 dB, Denny. If you're amplifying anyway, two dB up won't make much of a difference. Unless you have lots of background noise of course.

DSayers · Post by **DSayers** » April 10th, 2015, 11:40 am

Availle wrote:Our optimal loudness target is 89 dB, Denny. If you're amplifying anyway, two dB up won't make much of a difference. Unless you have lots of background noise of course.

I set up Audacity, watched their video on how to amplify and followed those steps. I loaded a copy of a Storm file I want to amplify. Choosing Effects>Amplify I get a dialog box that shows 0.0 dB above a slider. Typing in 0.89, the New Peak changes from 0.0 to 0.9 dB, and the OK button is grayed out. Clicking PREVIEW makes some changes, but then the dialog box returns to what it said before, and the options are still Preview and Cancel with OK grayed out. My file sounds just as loud as when I began.

Any ideas on how to actually amplify a file with Audacity?

-denny

tovarisch · Post by **tovarisch** » April 10th, 2015, 12:53 pm

It's possible that just a couple of samples in the file have the maximum value. You either need to allow clipping, or normalize the track first (I don't like the latter effect, personally). Or amplify portions of the track by selecting them before applying the 'amplify' effect -- it works on selection or on the entire track if nothing is selected.

Post by **TriciaG** » April 10th, 2015, 1:26 pm

It sounds like your recording is lower volume, but there are spikes which prevent further amplification because they'll clip.

Here's something you can do: compression. http://www.youtube.com/watch?v=wJ3lOTDsN6c
It will squish your spikes so that you can amplify a bit more.

My default settings are as follows:
Threshold: -17 dB
Noise Floor: -40 dB
Ratio: 2.5:1
Attack: 0.2
Decay: 1.0
NO checks in the check boxes

After compressing, amplify by a little more than you normally would - maybe .5 more, if you can - because this does make the file quieter.

DSayers · Post by **DSayers** » April 11th, 2015, 10:03 am

I got some amplification, I think. Could someone please check to see if this is at 0.89 dB or better?

https://librivox.org/uploads/carolin/storm_17_defoe_128k_copy.mp3

Thanks.

-denny

Post by **TriciaG** » April 11th, 2015, 10:08 am

It's at 87.0 dB. Good enough!

DSayers · Post by **DSayers** » April 11th, 2015, 11:11 am

TriciaG wrote:It's at 87.0 dB. Good enough!

Great news.

How do you determine what the dB level is? I need to know how to do this myself, if Audacity is going to serve as my "amplifier" in future. I don't want to have to keep asking "do you hear me now? do you hear me now? ...

Thanks.

-denny

Post by **knotyouraveragejo** » April 11th, 2015, 12:28 pm

Checking your volume, so that you know how much to amplify by: the easiest way is to install an extra plugin in Audacity that will tell you by how much the recording needs to be amplified to reach the desired volume of 89 dB.

Replay Gain plugin for Audacity: - http://forum.audacityteam.org/download/file.php?id=4668

Save the file to your computer - your desktop or somewhere where you can easily find it.
Now browse to the folder in which Audacity is installed. It's probably in C:\Program Files\Audacity) and then open the Plug-Ins folder.
Drag the file you saved into the Plug-Ins folder.
When next you start up Audacity, you will be able to select the whole recording (Ctrl+A on Windows), then go to Analyze | ReplayGain, and it'll tell you how much to amplify your file to get to about 89 dB.

DSayers · Post by **DSayers** » April 11th, 2015, 2:03 pm

knotyouraveragejo wrote:Checking your volume, so that you know how much to amplify by: the easiest way is to install an extra plugin in Audacity that will tell you by how much the recording needs to be amplified to reach the desired volume of 89 dB.

Wow, thanks so much. Very helpful.

-denny