I try to avoid discussing products, but there’s one that’s come to mind recently, available on Amazon for $5.88. It’s a book, Ray Wadsworth’s Basics of Audio and Visual Systems Design, in its original 1983 first edition. You can get it here https://www.amazon.com/Basics-Audio-Visual-Systems-Design/dp/0672220385, and it’s a treasure for anyone working in the field. Though of course dated, it lays out the mathematics and geometry that underpin the rules of thumb, online calculators, and received wisdom that we all rely on daily.
The book came to mind through conversation with another designer here concerning what we could and couldn’t ask of an integrator. Just the term “integrator” was a clue. Not a system builder, not a fabricator – an integrator takes purchased equipment and assembles it into a functioning whole. The days of circuit building, resistor color codes, and soldering irons are largely behind us. The equipment we use has become more capable and reliable, but expecting custom work is more difficult, the needed skills and willingness less common. Few integrators maintain bench repair facilities anymore. We’ve specialized, and become much more productive for it.
We’ve also left behind the term “AV Contractor,” and with it the implied ability to subcontract to allied trades. This may turn out to be shortsighted – if an integrator is reluctant to install a few electrical outlets, there are many electrical contractors who will happily sell AV equipment. Already we are including electrical contracting firms on our bid lists, those who have proven they can manage AV as a subcontract, and our experience with this approach has been good. Yes, the complex systems will always need specialty AV houses, but there’s an awful lot of work that doesn’t.
As for books, there’s a second edition (2003) of Basics of Audio and Visual Systems Design, also available on Amazon, more broad in scope but less foundational. Both are good resources for technical detail and for background understanding. And for current thinking, there are standards published by AVIXA https://www.avixa.org/standards/current-standards, the AV industry trade association.