Excellent website on recording history providing extensive informations, deeply educative.
Many subjects about the history of the technologies for recording music and sound are approached like :
The Business History of Sound Recording Technology
History of the Music Recording Industry
Technologies for Recording Music
The Eight Track Tape
Phonograph Records through the 78 rpm disc
How Records Were Manufactured
How Tape Was made
A link to bookmark and to patiently read from A to Z if you want to know it all.