There is an optional plug-in called [u]Wave Stats[/u]. (There seems to be a time-limit, and you may only be able to analyze 30 seconds at a time.)
Or, you can check the peaks by starting the Amplify. And, you can enter -3dB as the New Peak Amplitude and that will make the adjustment. You can cancel the effect if you just want to check without actually changing the levels.
Amplify and Wave Stats will give you the RMS and peak… I don’t know of a way to measure peaks “hovering around” a level, except by looking at the waveform. With the default settings, 1.0 is 0dB and -3dB is around 70% (0.7) You can change to a dB display, but it’s not easy to see where -3db is. For a voice recording, I’d probably Amplify the peak to 0dB, and check “hovering around” by looking at the waveform visually.
I think most audio editors have something like Wave Stats built in. I also use GoldWave ($60 USD), and I can get the peak & average, but I have to use “tricks” similar to using Amplify with Audacity.
[u]SOX[/u] (FREE) can give you the details/statistics if you are comfortable using a command-line program.
Now here’s the tricky part… The ratio* between the peak and average (or RMS) is constant… If you boost the volume by 6dB, the peak and average will both go up by 6dB. You may need to use compression, limiting or adjust the volume envelope in order to change the ratio and hit both targets.
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- Decibels are logarithmic so the difference (subtraction) is a ratio.