Michael Jackson's Bad was one of the first multi-track digital recordings ever made. It was a state-of-the-art recording with the dynamics of the recording being of the utmost importance. Bruce Swedien was the recording engineer that created this work of art. He used his “Acusonic Recording Process D”, which essentially was using stereo pairs of multi-tracks, instead of mono singles, the consequence being he had double the track count and therefore had to synchronise multi-track tape machines in parallel. This meant he could capture all of the natural decay and fade, between stereo channels, without loss, or inducing it artificially. Microphone placement and type were also very critical to Bruce in creating his sound.
He also eschewed compression: "I'm not a big fan of compression or limiting at all — I can't emphasise that enough. On many of the recordings that you hear today, all the excitement and all the colour is gone because they're so over‑compressed. I never did that. I would never have a compressor or limiter on the [master] bus, for instance. I want all that transient information there. And no compression or limiting on any drums or percussion. That's one of the biggest mistakes that I hear, I think, in modern pop recording. The stuff is so compressed they've limited the living doo‑doo out of the sound.”
"I'm a nutcase about details in the mix, so I'll use automation to a degree, but only very subtle compression. I have a pair of the new variety of [Universal Audio] LA2As that I just love, so I will use those, but it'll only just be tickling the meter, at the most one or two decibels. I don't like what happens to the sound when you compress any further, and that's very important to me.” - Bruce Swedien - Sound on Sound magazine
The entire process of this album was recorded Digitally on the Mitsubishi Multi-track and stereo master recorders.
So that leaves the question, how did an album with a Dynamic Range on the first release of CD, of 14, in 1987 get to a DR of 7? in 2012 with the 25th anniversary edition. Perhaps we need to ask Brian "Big Bass" Gardner at Bernie Grundman Mastering, why?