Owen T. Heisler

Technical Writer and Consultant

Professional Audio Speech Reinforcement

This collection of articles is the result of several years of working with speech reinforcement systems, doing research, testing hardware, and learning by trial-and-error. I do not claim to be an expert, but I do hope that this resource can be helpful for anyone who needs to set up, improve, maintain, or operate sound systems for speech reinforcement. Please note also that some articles are incomplete.

The primary focus here is on theory, so you can apply it in your particular situation with the hardware you already have. However, hardware choices are very important, and hardware suggestions are also offered. If you would like a ready-to-use complete system design instead, without the theory, please see Design 3.

The goal of a speech reinforcement system is to transport audio signal from a human speaker to the ears of each listener, and to maintain accuracy of the signal as much as possible.

Signal Path:

1. Human Speaker: Tips for speakers and details about human speech frequencies

2. Microphones: Selecting and using microphones and related equipment

3. Mixing and Processing: Theory and specific hardware related to the mixing part of the signal path

4. Room Speakers: Selecting, installing, and powering speakers

5. Assistive Listening: Providing audio for people with hearing loss or in other rooms outside of the normal listening area

6. Telephone Output: Sharing audio over the telephone

7. The Room: How the room affects audio and how to reduce loss of quality

8. Hearing: Understanding hearing, hearing loss, and comprehension as relates to audio

There are separate articles for the following topics:

• Taking Measurements: Using software and equipment to get objective details about what is happening with an audio signal

• Wiring and Cables: Signal levels, attenutators, cable types, distances, and gauges

• Power: Using uninterruptible power supplies (UPSes) for reliable power

• Storage: Choosing racks and other hardware for storing and transporting audio equipment

• General Notes: External links and related notes

And articles for particular system designs:

• Design 1: An old sound system design for speech reinforcement in large rooms

• Design 2: A simple sound system and accessories that can be used for speech reinforcement with a small audience

• Design 3: A highly flexible, automated sound system for speech reinforcement with large groups

  • Building Guide: Detailed information about building the system

  • User Guide: Instructions for setting up and using the system