Technical resources and articles
Linear Audio: magazine about engineering of high-quality audio electronics.
Elliot Sound Products (ESP): in-depth technical articles on different audio design subjects. I often use these as a source of inspiration for audioroot projects.
Hobby HiFi: magazine about DIY loudspeakers (such as the Cheap Trick 154) and quality audio design. Electronics
Loudspeaker drivers and parts
Other sites of interest:
The Audioasylum and DIYAudio: my preferred internet forums for custom audio design, very useful places to exchange and discuss new ideas for audioroot projects.
Audio site of Claudio Bonavolta: a HUGE collection of schematics and knowledge.
Dynamic Range Database: this database lists the dynamic ranges encountered with different records and albums. Too many records are flawed by compressed dynamics. Here you can find the good and the bad ones.