This notebook was used by Edison during the period December 1915-January 1916 for experiments pertaining to sound recording. Included are notes on the quality and loudness of recordings made with different numbered recorders, various arrangements of equipment and musicians in the recording studio, and different shapes of the recording chamber. One entry contains the notation, "we can control quality by chamber size to a great extent." The experimental recorders referred to in this notebook are described in earlier books by Absalom M. Kennedy, such as N-14-09-21. Many of them are evaluated by Edison and Kennedy in N-15-11-19, which also describes the outfit of the recording studio. Experiments involving the arrangement of the studio include changes in the location of musicians and instruments, the dampening of sound through various methods, the use of different instrumentation, and changes in the instruments. The locations of musicians in some recordings are indicated with reference to a numbered grid on the front flyleaf of the book. The front cover is marked "Edison." The pages are unnumbered. Approximately 70 pages have been used. Courtesy of Thomas Edison National Historical Park.