Audio Levels

Question

I now I can boost the audio levels in the timeline
but what is a good range for the recorded audio levels
when they first come in to FCP ?
I have footage that's coming in at -2.4 dbs and peaking
a little above that and under -1.8
I assume this is lower than optimum
thanks

Answer 1

The dynamic range of your mix is dependent on the final viewing environment. For example, movie theaters have large, relatively expensive sound systems that can reproduce a large dynamic range. Television speakers are much smaller, and often the listening environment has more ambient noise, so very quiet sounds may not even be noticeable unless the overall signal is compressed and the level increased, which reduces the dynamic range.
For example, television stations normally accommodate only 6 dB between the average loudness and the peaks. Dolby Digital feature film soundtracks, on the other hand, can accommodate up to 20 dB between average and peak levels. This is why loud sounds in a movie theater sound so loud: they are much louder than the average level.
When you mix your final audio, you choose a consistent reference for the average level. When you choose the average reference level, you are actually choosing how much additional headroom you have before your signal distorts. The higher you set the average level, the less safety margin you have for peaks in the signal. This means that the loudest sounds in your mix cannot be much louder than the average levels, and so the mix is less dynamic.
Acceptable amount of dynamic range:
Theatrical Dolby Digital 20 dB
Average videotape 12 dB
Television broadcast 6 dB
If you set the reference level of the Final Cut Pro floating audio meter to –20 dBFS, you have nearly 20 dB of headroom, since 0 dBFS is the digital limit for the loudest sound. If you set the reference level in your sequence to –12 dBFS instead, you have less headroom. Even though the average level of your audio is higher, there won’t be as much dynamic range.
How much dynamic range you allow in your audio mix depends on its ultimate destination. If you’re editing a program for TV broadcast, a reference level of –12 dBFS is fine, since you are only allowed 6 dB of dynamic range anyway. But if you’re working on a production to be shown in movie theaters, consider using a reference level closer to –18 or even –20 dBFS (both of these are frequently used standards).
Remember that the ultimate goal is to ensure that audio doesn’t peak over 0 dBFS in your mix (as displayed in the Final Cut Pro audio meters) and won’t peak over +3 dB or so on an analog meter.
With a little help from the Final Cut Pro User Manual, "Audio Levels, Meters, and Output Channels". Pages 58 - 59.