Associations  

ASCAP

Audio Engineering Society  

SPARS

Audio Sites & Blogs:

Behind the Mixer 

Dave Rat Blog

Digido - Audio FAQ

Doctor ProAudio 

FOH Online

Free Loops

Lighting and Sound America

Massive Mastering - Blog

Media College

Mix Magazine

Music 3.0

Pensados Place

Pro Audio Files 

Pro Sound Web 

Pro Tools Expert

Production Advice

Rational Acoustics 

Shaking Through

SynAudCon

Tape Op Magazine

The Physics of Sound

The Recording Revolution 

UA Blog 

Manufacturers:

Avid 

Lavry

Meyer Sound 

Shure

Waves

Online Calculators and Tools:

Acoustic and Vibration Animations

Audio Calculators

Audio Check.net

Paul Falstad - Tons of audio & physics applets!

Metronome Online

Studio and Audio Calculations

Smart People:

Bob McCarthy

Ethan Winer

Leslie Ann Jones

Manny Marroquin

Michael Brauer

Pro Audio Resources