Recording studio

Recording studios generally consist of three or more rooms:

• The live room of the studio is where instrumentalists play their instruments, with their playing picked up by microphones and, for electric and electronic instruments, by connecting the instruments' outputs or DI unit outputs to the mixing board as well as a place where vocalists may perform;[1]
• Isolation booths, or sound enclosures are either enclosed or partially enclosed areas built out of boxes or partitions or are completely separate small sound-insulated rooms with doors, designed for certain instrumentalists (or their loud speaker stacks). Vocal booths are similarly designed rooms for singers. In both types of rooms, there are typically windows so the performers can see other band members and other studio staff, as singers, bandleaders and musicians often give or receive visual cues;[1]
• The control room, or production/recording room, is where the audio engineers and record producers mix the mic and instrument signals with a mixing console. From here, they can record the singing and playing onto tape (until the 1980s and early 1990s) or hard disc (1990s and following decades) and listen to the recordings and tracks with monitor speakers or headphones and manipulate the tracks by adjusting the mixing console settings and by using effects units;[1]
• The machine room, where noisier equipment, such as racks of fan-cooled computers and power amplifiers, is kept to prevent the noise from interfering with the recording process.

Even though sound isolation is a key goal, the musicians, singers, audio engineers and record producers still need to be able to see each other, to see cue gestures and conducting by a bandleader. As such, the live room, isolation booths, vocal booths and control room typically have windows.

Neve VR60, a multitrack mixing console. Above the console are a range of studio monitor speakers.

Recording studios are carefully designed around the principles of room acoustics to create a set of spaces with the acoustical properties required for recording sound with accuracy. Architectural acoustics includes acoustical treatment and soundproofing and also the consideration of the physical dimensions of the room itself to make the room respond to sound in the desired way. Acoustical treatment includes and the use of absorption and diffusion materials on the surfaces inside the room. To control the amount of reverberation, rooms in a recording studio may have a reconfigurable combination of reflective and non-reflective surfaces. Soundproofing provides sonic isolation between rooms and prevents sound from entering or leaving the property. A Recording studio in an urban environment must be soundproofed on its outer shell to prevent noises from the surrounding streets and roads from being picked up by microphones inside.

Engineers and producers watch a trumpet player from a window in the control room during a recording session.

Equipment found in a recording studio commonly includes:

• A professional-grade mixing console
• Additional small mixing consoles for adding more channels (e.g., if a drum kit needs to be miked and all of the channels of the large console are in use, an additional 16 channel mixer would enable the engineers to mix the mics for the kit)
• Microphone preamplifiers
• Multitrack recorder or digital audio workstation
• Computers
• A wide selection of microphones typical for different types of instruments
• DI unit boxes
• Microphone stands to enable engineers to place microphones at the desired locations in front of singers, instrumentalists or ensembles
• Studio monitors designed for listening to recorded mixes or tracks
• Studio monitoring headphones (typically closed-shell, to prevent sound from "leaking" out into the microphones)
• "On Air" or "Recording" lighted signs to remind other studio users to be quiet
• Outboard effect units, such as compressors, reverbs, or equalizers
• Music stands

A selection of instruments at a music studio, including a grand piano

Not all music studios are equipped with musical instruments. Some smaller studios do not have instruments, and bands and artists are expected to bring their own instruments, amplifiers, and speakers. However, major recording studios often have a selection of instruments in their live room, typically instruments, amplifiers and speaker cabinets that are large, heavy, and difficult to transport (e.g., a Hammond organ) or infeasible (as in the case of a grand piano) to hire for a single recording session. Having musical instruments and equipment in the studio creates additional costs for a studio, as pianos have to be tuned and instruments and associated equipment needs to be maintained.

In the era of acoustical recordings (prior to the introduction of microphones, electrical recording and amplification), the earliest recording studios were very basic facilities, being essentially soundproof rooms that isolated the performers from outside noise. During this era it was not uncommon for recordings to be made in any available location, such as a local ballroom, using portable acoustic recording equipment. In this period, master recordings were made by cutting a rotating cylinder (later disc) made from wax. Performers were typically grouped around a large acoustic horn (an enlarged version of the familiar gramophone horn). The acoustic energy from the voices or instruments was channeled through the horn to a diaphragm to a mechanical cutting lathe, which inscribed the signal as a modulated groove directly onto the surface of the master.

The Siemens Studio for Electronic Music c. 1956.

Electrical recording was common by the early 1930s, and mastering lathes were electrically powered, but master recordings still had to be cut into a disc, by now a lacquer, also known as an Acetate disc. In line with the prevailing musical trends, studios in this period were primarily designed for the live recording of symphony orchestras and other large instrumental ensembles. Engineers soon found that large, reverberant spaces like concert halls created a vibrant acoustic signature as the natural reverb enhanced the sound of the recording. In this period large, acoustically live halls were favored, rather than the acoustically dead booths and studio rooms that became common after the 1960s. Because of the limits of the recording technology, which did not allow for multitrack recording techniques, studios of the mid-20th century were designed around the concept of grouping musicians (e.g., the rhythm section or a horn section) and singers (e.g., a group of backup singers), rather than separating them, and placing the performers and the microphones strategically to capture the complex acoustic and harmonic interplay that emerged during the performance. In the 2000s, modern sound stages still sometimes use this approach for large film scoring projects that use large orchestras.

Because of their superb acoustics, many of the larger studios were converted churches. Examples include George Martin's AIR Studios in London, Columbia Records 30th Street Studio in New York City,[6] and Pythian Temple studio in New York.

Facilities like the Columbia Records 30th Street Studio in New York and Abbey Road Studios in London were renowned for their identifiable sound—which was (and still is) easily identifiable by audio professionals—and for the skill of their staff engineers. As the need to transfer audio material between different studios grew, there was an increasing demand for standardization in studio design across the recording industry, and Westlake Recording Studios in West Hollywood was highly influential in the 1970s in the development of standardized acoustic design.[7]

In New York City, Columbia Records had some of the most highly respected sound recording studios, including the 30th Street Studio at 207 East 30th Street, the CBS Studio Building at 49 East 52nd Street, Liederkranz Hall at 111 East 58th Street between Park and Lexington Avenues (a building built by and formerly belonging to a German cultural and musical society, The Liederkranz Club and Society),[8][9] and one of their earliest recording studios, Studio A at 799 Seventh Avenue.[6]

Donna Summer wearing headphones during a recording session in 1977

Danny Knicely records with Furnace Mountain Band in Virginia (2012)

Electric recording studios in the mid-20th century often lacked isolation booths, sound baffles, and sometimes even speakers. A major reason that isolation was not used was that recordings in this period were typically made as live ensemble takes and all the performers needed to be able to see each other and the ensemble leader while playing. The recording engineers who trained in this period learned to take advantage of the complex acoustic effects that could be created through leakage between different microphones and groups of instruments, and these technicians became extremely skilled at capturing the unique acoustic properties of their studios and the musicians in performance. It was not until the 1960s, with the introduction of the high-fidelity headphones that it became common practice for performers to use these to monitor their performance during recording and listen to playbacks.

The use of different kinds of microphones and their placement around the studio is a crucial part of the recording process, and particular brands of microphones are used by engineers for their specific audio characteristics. The smooth-toned ribbon microphones developed by the RCA company in the 1930s were crucial to the crooning style perfected by Bing Crosby, and the famous Neumann U47 condenser microphone was one of the most widely used from the 1950s. This model is still widely regarded by audio professionals as one of the best microphones of its type ever made. Learning the correct placement of microphones is a major part of the training of young engineers, and many became extremely skilled in this craft. Well into the 1960s, in the classical field it was not uncommon for engineers to make high-quality orchestral recordings using only one or two microphones suspended above the orchestra. In the 1960s, engineers began experimenting with placing microphones much closer to instruments than had previously been the norm. The distinctive rasping tone of the horn sections on the Beatles recordings "Good Morning Good Morning" and "Lady Madonna" were achieved by having the saxophone players position their instruments so that microphones were virtually inside the mouth of the horn.

The unique sonic characteristics of the major studios imparted a special character to many of the most famous popular recordings of the 1950s and 1960s, and the recording companies jealously guarded these facilities. According to sound historian David Simons, after Columbia took over the 30th Street Studios in the late 1940s and A&R manager Mitch Miller had tweaked it to perfection, Miller issued a standing order that the drapes and other fittings were not to be touched, and the cleaners had specific orders never to mop the bare wooden floor for fear it might alter the acoustic properties of the hall. There were several other features of studios in this period that contributed to their unique sonic signatures.

As well as the inherent sound of the large recording rooms, many of the best studios incorporated specially-designed echo chambers, purpose-built rooms which were often built beneath the main studio. These were typically long, low rectangular spaces constructed from hard, sound-reflective materials like concrete, fitted with a loudspeaker at one end and one or more microphones at the other. During a recording session, a signal from one or more of the microphones in the studio could be routed to the loudspeaker in the echo chamber; the sound from the speaker reverberated through the chamber and the enhanced signal was picked up by the microphone at the other end. This echo-enhanced signal, which was often used to sweeten the sound of vocals, could then be blended in with the primary signal from the microphone in the studio and mixed into the track as the master recording was being made.

Special equipment was another notable feature of the classic recording studio. The biggest studios were owned and operated by large media companies like RCA, Columbia and EMI, who typically had their own electronics research and development divisions that designed and built custom-made recording equipment and mixing consoles for their studios. Likewise, the smaller independent studios were often owned by skilled electronics engineers who designed and built their own desks and other equipment. A good example of this is Gold Star Studios in Los Angeles, the site of many famous American pop recordings of the 1960s. Co-owner David S. Gold built the studio's main mixing desk and many additional pieces of equipment and he also designed the studio's unique trapezoidal echo chambers.

During the 1950s and 1960s, the sound of pop recordings was further defined by the introduction of proprietary sound processing devices such as equalizers and compressors, which were manufactured by specialist electronics companies. One of the best known of these was the Pultec equalizer which was used by almost all the major commercial studios of the time.

With the introduction of multi-track recording, it became possible to record instruments and singers separately and at different times on different tracks on tape. In the mid-20th century, recordings were analog, made on 1⁄4-inch or 1⁄2-inch magnetic tape, or, more rarely, on 35 mm magnetic film, with multitrack recording reaching 8 tracks in the 1950s, 16 in 1968, and 32 in the 1970s. The commonest such tape is the 2-inch analog, capable of containing up to 24 individual tracks. Throughout the 1960s many pop classics were still recorded live in a single take. In the 1970s the large recording companies began to adopt multi-track recording and the emphasis shifted to isolation and sound-proofing, with treatments like echo and reverberation added separately during the mixing process, rather than being blended in during the recording. Generally, after an audio mix is set up on a 24-track tape machine, the tracks are played back together, mixed and sent to a different machine, which records the combined signals (called printing) to a 1⁄2-inch two-track stereo tape, called a master.

Before digital recording, the total number of available tracks onto which one could record was measured in multiples of 24, based on the number of 24-track tape machines being used. Most recording studios now use digital recording equipment, which limits the number of available tracks only on the basis of the mixing console's or computer hardware interface's capacity and the ability of the hardware to cope with processing demands. Analog tape machines are still used in some cases for their unique sonic characteristics.