Equipment found in a recording studio commonly includes:
Equipment may also include:
Current software applications are more reliant on the audio recording hardware than the computer they are running on, therefore typical high-end computer hardware is less of a priority. While Apple Macintosh is common for studio work, there is a breadth of software available for Microsoft Windows and Linux. A sizeable portion of both commercial and home studios can be seen running PC-based multitrack audio software.
If no mixing console is used and all mixing is done using only a keyboard and mouse, this is referred to as mixing in the box. There are also dedicated machines which integrate a recorder, preamps, effects, and a mixing console; these devices are frequently referred to as DAW's, generally in advertising.
Recording drums and electric guitar in a home studio is challenging, because they are usually the loudest instruments. Conventional drums require soundproofing in this scenario, unlike electronic or sampled drums. Getting an authentic electric guitar amp sound including power-tube distortion requires a power attenuator (either power-soak or power-supply based) or an isolation box or booth. A convenient compromise is amp simulation, whether a modelling amp, preamp/processor, or software-based guitar amp simulator. Sometimes, musicians replace loud, inconvenient instruments such as drums, with keyboards, which today often provide somewhat realistic sampling.
There are variations of the same concept, including a portable standalone isolation booth, a compact guitar speaker isolation cabinet, or a larger guitar speaker cabinet isolation box.
A gobo panel achieves the same idea to a much more moderate extent; for example, a drum kit that is too loud in the live room or on stage can have acrylic glass see-through gobo panels placed around it to deflect the sound and keep it from bleeding into the other microphones, allowing more independent control of each instrument channel at the mixing board.
All rooms in a recording studio may have a reconfigurable combination of reflective and non-reflective surfaces, to control the amount of reverberation.
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 a direct-to-disc cutting process -- performers were typically grouped around a large acoustic horn (an enlarged version of the familiar phonograph horn) and the acoustic energy from the voices and/or instruments was channeled through the horn's diaphragm to a mechanical cutting lathe located in the next room, which inscribed the signal as a modulated groove directly onto the surface of the master cylinder or disc.
Following the invention and commercial introduction of the microphone, the electronic amplifier, the mixing desk and the loudspeaker, the recording industry gradually converted to electric recording and this technology had replaced mechanical acoustic recording methods in 1925 for major labels like RCA Victor and Columbia, and by 1933 acoustic recording was completely disused.
Electrical recording was common by the early 1930s, and mastering lathes were now electrically powered, but master recordings still had to be cut direct-to-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 that greatly enhanced the sound of the recording, and 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, studios of the mid-20th century were designed around the concept of grouping musicians and 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. Modern sound stages still sometimes use this approach for large film scoring projects today.
Because of their superb acoustics, many of the larger studios were converted churches. Examples include George Martin's AIR Studios in London, the famed Columbia Records 30th Street Studio in New York City (a converted Armenian church, with a ceiling over 100 feet high), and the equally famous Decca Records Pythian Temple studio in New York (where artists like Louis Jordan, Bill Haley and Buddy Holly were recorded) which was also a large converted church that featured a high, domed ceiling in the center of the hall.
Electric recording studios in the mid-20th century often lacked isolation booths, baffles, and sometimes even speakers, and it was not until the 1960s, with the introduction of the high-fidelity headphones that it became common practice for performers to use headsets to monitor their performance during recording and listen to playbacks.
It was difficult to isolate all the performers -- a major reason that this practice was not used was simply because recordings were usually 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 though "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.
Facilities like the Columbia Records 30th Street Studio in New York and EMI's Abbey Road Studio in London were renowned for their 'trademark' sound -- which was (and still is) easily identifiable by audio professionals -- and for the skill of their staff engineers.
The use of different kinds of microphones and their placement around the studio was a crucial part of the recording process, and particular brands of microphone were 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 was 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, A&R manager Mitch Miller issued a standing order that the drapes and other fittings left by the previous occupants 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 the famous 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 famous 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, although it was not until the 1970s that the large recording companies began to adopt this practice widely, and throughout the Sixties many "pop" classics were still recorded live in a single take.
After the Sixties 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. One regrettable outcome of this trend, which coincided with rising inner-city property values, was that many of the largest studios were either demolished or redeveloped for other uses.
In the 1960s, recordings were analog recordings made using ¼-inch or ½-inch two-track magnetic tape. By the early 1970s, the technology progressed to using various types of multi-track tape. The most common of which is the 2-inch analog tape, capable of containing up to 24 individual tracks. Generally after an audio mix is set up on a 24-track tape machine, the signal is played back and sent to a different machine which records the combined signals (called printing) to a ½-inch 2-track stereo tape, called a master.
Prior to 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. Presently, most recording studios now use digital recording equipment which only limits the number of available tracks based on the capacity of the mixing console or computer hardware interface.
Analog tape machines are still well sought after as some purists label digitally recorded audio as sounding too harsh, and the scarcity and age of analog tape machines greatly increases their value, as does the fact that many audio engineers still insist on recording only to analog tape. This harshness is widely attributed by them to the fact that digital recording will sample a sound wave many times per second allowing an illusion of solid sound waves to be created, where in contrast, analog tape captures a sound wave in its entirety.
However, others simply argue that the lack of high frequency noise and the higher fidelity of the digital medium make the recorded higher frequencies more prominent, which results in such perceived harshness in contrast to analog recording. Still others point to problems of early digital recordings caused by the inexperience of sound engineers with the new medium as the cause for critics to the digital systems. Finally, another possibly relevant effect derives from the fact that, since CD-quality audio uses a sampling rate of 44.1 kHz, no frequencies above the Nyquist frequency of 22050 Hz are acceptable for recording, otherwise aliasing occurs. Because of that, very steep low-pass filters are used on frequencies above 20 kHz (the theoretical limit for human hearing) that introduce slight distortions into the audible-range signal. This is one of the several reasons for the push on high-end equipment towards higher sampling rates, such as 48 kHz (used in video production), 88.2 kHz, 96 kHz and even 192 kHz.
Broadcast studios also use many of the same principles such as sound isolation, with adaptations suited to the live on-air nature of their use. Such equipment would commonly include a telephone hybrid for putting telephone calls on the air, a POTS codec for receiving remote broadcasts, a dead air alarm for detecting unexpected silence, and a broadcast delay for dropping anything from coughs to profanity. In the U.S., FCC-licensed stations also must have an Emergency Alert System decoder (typically in the studio), and in the case of full-power stations, an encoder that can interrupt programming on all channels which a station transmits in order to broadcast urgent warnings.
Computers are also used for playing ads, jingles, bumpers, soundbites, phone calls, sound effects, traffic and weather reports, and now full broadcast automation when nobody is around. For talk shows, a producer and/or assistant in a control room runs the show, including screening calls and entering the callers' names and subject into a queue, which the show's host can see and make a proper introduction with. Radio contest winners can also be edited on the fly and put on the air within a minute or two after they have been recorded accepting their prize.
Additionally, digital mixing consoles can be interconnected via audio over Ethernet, or split into two parts, with inputs and outputs wired to a rackmount audio engine, and one or more control surfaces (mixing boards) and/or computers connected via serial port, allowing the producer or the talent to control the show from either point. With Ethernet and audio over IP (live) or  (recorded), this also allows remote access, so that DJs can do shows from a home studio via ISDN or Internet. Additional outside audio connections are required for the studio/transmitter link for over-the-air stations, satellite dishes for sending and receiving shows, and for webcasting or podcasting.