The need for a general collection of electroacoustical reference and design data in graphical form has been felt by acousticians and engineers for some time. This type of data can otherwise only be found in a collection of handbooks. Therefore, it is the authors intention that this book serve as a single source for many electroacoustical reference and system design requirements. In form, the volume closely resembles Frank Massas Acoustic Design Charts, a handy book dating from 1942 that has long been out of print. The basic format of Massas book has been followed here: For each entry, graphical data are presented on the right page, while text, examples, and refer­ ences appear on the left page. In this manner, the user can solve a given problem without thumbing from one page to the next. All graphs and charts have been scaled for ease in data entry and reading. The book is divided into the following sections: A. General Acoustical Relationships. This section covers the behavior of sound transmis­ sion in reverberant and free fields, sound absorption and diffraction, and directional characteris­ tics of basic sound radiators. B. Loudspeakers. Loudspeakers are discussed in terms of basic relationships regarding cone excursion, sensitivity, efficiency, and directivity index, power ratings, and architectural layout. c. Microphones. The topics in this section include microphone sensitivity and noise rating, analysis of directional properties, stereo microphone array characteristics, proximity effects, and boundary conditions. D. Signal Transmission.