Peak programme meter. A typical British quasi-PPM.
Each division between '1' and '7' is exactly four decibels and '6' is the intended maximum level. There are many different kinds of PPM. They fall into broad categories: True peak programme meter. Bob Katz - music mastering and loudness Part 1. Mastering Audio by Bob Katz. Audio mastering. Mastering requires critical listening; however, software tools exist to facilitate the process.
Results still depend upon the accuracy of speaker monitors and the listening environment. Mastering engineers may also need to apply corrective equalization and dynamic enhancement in order to optimise sound translation on all playback systems.[1] It is standard practice to make a copy of a master recording, known as a safety copy, in case the master is lost, damaged or stolen.