Page 9 - 2013 Spring

ACOUSTICS OF RECORDING STUDIOS
Marshall Long
Marshall Long Acoustics 13636 Riverside Drive Sherman Oaks, California 91423
“Foley stages...
are often indistinguishable from junkyards, due to the general clutter.”
Process and environment
The recording of music, either
voice or instrumental, is a core
industry supporting the enter-
tainment arts. The process begins with
the production of music in a studio.
Here the audio generated by a musical
instrument is captured by a transducer,
either a microphone or an electronic pickup built into the instrument itself. The electronic signal from the micro- phone is transmitted to a control room where it is routed through various electronic devices and stored for future use. The signals may be in analog or digital format and may be transmitted via electrical or fiber optic cables or by means of a wireless transmitter. The signal can subsequent- ly be played back and remixed, stored, or combined with other recorded signals until the final product has been pro- duced. It is then packaged as part of a storage device for later presentation in commercial or home theaters, or dis- tributed electronically to a playback or other receiver sys- tem. This issue of Acoustics Today will deal with aspects of the interaction between these processes and the acoustical spaces in which they occur.
Studios
A studio, in the most general sense of the word, is a space where music is played, recorded, and edited. In a narrower sense it is where music is played and captured by a micro- phone. A control room is a separate room where one or more mixers work and music is played back, edited, and stored.
Studios can range in size, from a closet to scoring stages accommodating a full symphony orchestra. Figure 1 shows sketches of several different types. In small home studios the mix board and other electronic equipment is located in the same space as the musicians. In larger facilities these func- tions are separated into different rooms, which may in turn be subdivided. All studios have common requirements irre-
spective of size. There may, in addition, be specialized requirements which are size dependent or function dependent. A summary of the common require- ments is listed in Table 1 below. Some of these are acoustical in nature while oth- ers are purely functional.
Home studios
Home studios, sometimes known as project studios, are increasingly common as high quality recording equipment becomes smaller and more affordable. The sophistication of this electronic gear has had a direct influence on the prolifer- ation of small studios since excellent recordings can now be made in a low-cost environment. The initial reaction from commercial studios was an effort to limit home studios through land-use regulations. A decade or two ago, under pressure from the commercial studio owners, Los Angeles prohibited people from using their homes to make commer- cial recordings. This led the City of Los Angeles, with the worst smog in the country, to require that people get into their cars and drive to a commercial studio to do their work, while raising the cost of the process. Under the cost pres- sures, rather than environmental enlightenment, the amount of time given to prepare the audio for a 45 minute television program has decreased from a week to about two days. Mixers now spend one day doing the bulk of the work in a home studio and a second day presenting it to the “suits” and transferring the results into the studio memory banks. The home studios can be equipped with the same equipment as the commercial studio, so after getting the executive input, changes can be made at the commercial site with no loss in quality.
The second problem confronting a home studio user is that regulations in residential neighborhoods restrict noise levels at neighboring properties. These property-line ordi- nances typically limit nighttime noise levels to 45 dBA or 5 dB
Acoustical Quiet – below NC 20
Isolation from the surroundings Adequate reverberation Freedom from acoustical defects Reasonable diffusion
Isolation for different instruments Control of bass reverberation Variable absorption
Moveable gobos (reflecting or
absorbing acoustic panels)
Functional
Adequate ventilation and thermal control
Access to bathrooms
Visual contact with the control room Storage areas
Equipment maintenance facilities Break rooms and private phone areas Communication areas (internet access) Offices and conference rooms Handicapped access
Access to cabling
Table 1 – Common Studio Requirements
8 Acoustics Today, April 2013