To open the Audio Tool, use either of the following methods:
Tools Menu | Audio Tool
cmd/Ctrl + 1
The measurement scale on the left-hand side is digital and uses the decibel scale, which is written as dB.
The measurement scale on the right references the analog Volume Units scale, which is written as VU.
On the digital scale, the highest value is zero. Audio above this level is clipped, and this is very undesirable as digital clipping causes distortion, making it sound terrible. On the VU scale, clipping occurs at approximately 20 VU. After doing some mathematical calculations, it works out that -20 dB on the digital scale equates to 0 VU on the analog scale...