I teach a hands-on class for small groups of audio equipment installers. The photos show some of the hands-on devices used during the class. Many of the lessons allow changes to be heard as capacitance, inductance, impedance, turns ratios, wiring errors, and balanced to unbalanced changes occur. I started developing this class in the 1980's and more than 200 people have gone through it. I've also taught classes at InfoComm. Training is the best investment you can make in your employees.