Sound equipment

Professional audio, also 'pro audio', refers to both an activity and a type of audio equipment. Typically it encompasses the production or reproduction of sound for an audience, by individuals who do such work as an occupation like live event support, using sound reinforcement systems designed for the purpose. (By contrast, consumer audio is usually confined to the reproduction of sound in the home.) Professional audio can include but is not limited to broadcast radio, audio mastering in arecording studio, television studio, sound reinforcement such as a concert, DJ performances, Audio sampling, public address, surround sound movie theatres, and in some cases piped music application.
The term 'professional audio' has no precise definition, but its typical features may include:
  • Operations carried out by technicians with at least some formal training
  • The capturing of sound with one or more microphones
  • Balancing sound from multitrack recording devices using a mixing console
  • The control of audio levels using standardized types of metering
  • Sound signals passing through lengthy signal chains involving processes at different times and places, involving a variety of skills
  • Compliance with organizational, national and international
practices and standards established by such bodies as the International Telecommunications Union, Audio Engineering Society and European Broadcasting Union.

Compared to consumer audio equipment, professional audio equipment tends to have such characteristics as:
  • Much greater mechanical robustness
  • Heavy-duty industrial-grade connectors, e.g. XLR and Speakon
  • 19-inch rack-mount construction
  • Balanced audio interfaces
  • Higher analog audio signal levels of 0 dBu or more
  • AES/EBU digital audio interfaces
The broadcast quality of professional audio equipment is on a par with that of consumer high-end audio equipment, but is more likely to be designed purely on sound engineering principles and owe little to a consumer oriented audiophile sub-culture.

A public address system (PA system) is an electronic sound amplification and distribution system with a microphone, amplifier andloudspeakers, used to allow a person to address a large public, for example for announcements of movements at large and noisy air and rail terminals.

The term is also used for systems which may additionally have a mixing console, and amplifiers and loudspeakers suitable for music as well as speech, used to reinforce a sound source, such as recorded music or a person giving a speech or distributing the sound throughout a venue or building.

Simple PA systems are often used in small venues such as school auditoriums, churches, and small bars. PA systems with many speakers are widely used to make announcements in public, institutional and commercial buildings and locations. Intercom systems, installed in many buildings, have microphones in many rooms allowing the occupants to respond to announcements.

Sound reinforcement systems and PA systems may use some similar components, but with differing application, although the distinction between the two is not clear-cut. Sound reinforcement systems are for live music or performance, whereas PA systems are primarily for reproduction of speech.[1] In Britain any PA system is sometimes colloquially referred to as a Tannoy, after the company of that name now owned by TC Electronic Group, which supplied a great many of the PA systems used in the past.

Some analog or IP private branch exchange (PBX) telephone systems use a paging facility that acts as a liaison between the telephone and a PA amplifier. In other systems, paging equipment is not built into the telephone system. Instead the system includes a separate paging controller connected to a trunk port of the telephone system. The paging controller is accessed as either a designated directory number or central office line. In many modern systems, the paging function is integrated into the telephone system, and allows announcements to be played over the phone speakers.

Many retailers and offices choose to use the telephone system as the sole access point for the paging system, because the features are integrated. Many schools and other larger institutions are no longer using the large, bulky microphone PA systems and have switched to telephone system paging, as it can be accessed from many different points in the school.

PA over IP refers to PA paging and intercom systems that use an Ethernet or GSM-R network instead of a centralized amplifier to distribute the audio signal to all paging locations in a building or campus. Network-attached amplifiers and intercom units are used to provide the communication function. At the transmission end, a computer application transmits a digital audio stream via the local area network, using audio from the computer's sound card inputs or from stored audio recordings. At the receiving end, specialized intercom modules (sometimes known as IP speakers) receive these network transmissions and reproduce the analog audio signal. These are small specialized network appliances addressable by an IP address just like any other computer on the network.

Such systems are inter-connected by the networking infrastructure and thus allow loss less transmission to remote locations across the Internet or a local area or campus network. It is also possible to provide for multiple or relocatable transmission control stations on such a network.