Page 16 - 2013 Spring

CONTROL ROOM DESIGN:
THE MONITORING ENVIRONMENT
George L. Augspurger
Perception Inc.
1537 Cerro Gordo Street Los Angeles, California 90026
Introduction
The idea that the control room should function as a reference listening environment dates from about 1966. By then, 8-track recording was common, but the process of combining all 8 tracks into a 2-channel stereo master was still in the experimental stage. RCA Records had opened large, new studios in sever- al U.S. cities. These were designed by
John Volkman to meet the special requirements of multi- track recording, and he established acoustical goals for the control rooms as well as the studio spaces.
Also in 1966, the British Broadcasting Corporation standardized basic acoustical requirements for broadcast control rooms, based on the belief that: “listening rooms and control rooms should not be very dissimilar from the aver- age conditions encountered in private houses.” BBC control rooms were therefore designed to have reverberation times of 0.4 second up to 250 Hz, gradually decreasing to 0.3 sec- ond at 8 kHz.1
By 1969 the number of tracks for music recording had increased to 16 and it became apparent that monitor loud- speakers should serve as a reference for the final 2-channel product rather than providing dedicated sound sources for individual tracks. Instead of the BBC’s simulated living room, the mixing environment became a kind of acoustical magnifying glass. As an example, the Los Angeles Record Plant opened in 1969 as one of the world’s first 16-track recording facilities. Control rooms, designed by Tom Hidley, looked more like space ship cockpits than conventional lis- tening rooms.
Each control room had a pair of high-power, custom- designed monitor loudspeakers flushed into a tilted wall above the studio window. The speakers abutted a hard, slop- ing ceiling that descended to a height of about 7 feet above the work area. In the rear third of the room the ceiling leveled off and was covered with absorptive treatment. The large 16- track console was located near the center of the room, pro- viding a fairly wide area in which stereo playback could be judged. Hidley’s goal was to provide an accurate stereo image in the console working area and not worry about the remain- der of the room. As a bonus, the “compression ceiling” deliv- ered powerful, gut-punching bass that was a new experience for recording engineers.
The next ten years saw a further increase in the number of recording channels from 16 to 32. It also saw a prolifera- tion of new control room design philosophies, each charac- terized by its own technical jargon, such as compression ceil- ing, live-end-dead-end, Haas fushion process, bass trap, quadratic residue diffusor, and reflection-free zone. F. Alton
The term “control room” originat-
ed in radio broadcasting and was
later adopted by the music
recording industry. In the early days of
disk recording, the control room was
little more than a booth, and it is still
called a “cabina” in Latin-American
countries. Today, the room is much
larger, perhaps 18 by 25 feet. It is used
actual recording process (“tracking”) and to assemble the multiple tracks into a final 2-channel or surround sound product (“mixing”). In a large music recording facility, mix- ing may be performed in a separate, dedicated room. If the product is to be released as a music album it will be sent to a mastering facility for a final check. The mastering engi- neer usually adds minor electronic processing, but may rec- ommend re-mixing certain portions before the recording is released. A third type of monitoring environment is a pro- duction studio (or “composer’s room”) in which music is both created and edited.
Historical Perspective
Before the introduction of audio tape recording in the late 1940s, commercial music was recorded direct-to-disk. In the U.S., the control booth was usually a small, utilitarian space adjacent to the recording studio. A window, perhaps 3 feet high by 5 feet wide, provided visual contact between the two rooms. The cutting lathe and a small audio control panel were located close to the window, giving the operator a good view of the studio. An ordinary radio-quality loudspeaker in a box was mounted on the wall above or beside the window. The only acoustic treatment consisted of perforated fiber tiles on the ceiling and upper wall areas.
The Capitol Records Tower in Hollywood, containing two state-of-the-art recording studios, was constructed in 1956. Each control room was a triangular structure built across one corner of the studio. At that time most record- ings at Capitol were made on 3-channel tape, with one or two microphones routed to each channel. Three-channel master tapes made it easy to release albums as mono or (after 1958) stereo LP disks. The audio control board was placed against a wide studio window, and three loudspeak- ers (one for each channel) were set in an alcove above the window. Recording engineers had access to a patch bay and a fair amount of audio processing gear—mostly equalizers and limiters. Tape machines were located in the rear corner. Although a great deal of attention was given to the acoustics of the studios, the control rooms were not intended to be critical listening spaces.
“The bulk of music produced in the U.S. today probably comes from residential studios.”
both to control the
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