Unfortunately, since GarageBand doesn't display dB numerical values on its volume meters, I wanted to create a visual reference guide for those of us that need to see the audio level in decibels. If you're editing your podcast in GarageBand or recording vocals for a new song, here's a way for you to gauge your volume level.
In Logic Pro X, I created a sine wave at standard target dB levels that we would want to benchmark in GarageBand: 0, -6, -12, -24, -36
I imported and marked the target dB levels on the volume meter in GarageBand. All track faders were set to 0 dB, which is the default setting when a new Audio Track is created.
Here's a closer view for you to reference:
Now you have a visual that can be referenced so you can get a better idea of your audio level!