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BACKGROUND
MUSIC
Please click on thumbnail to view larger image Background music in public places: prerecorded, usually easy-listening music played through speakers in public places and some workplaces to create a soothing atmosphere.
Public address system, abbreviated PA system, is an electronic amplification system used as a communication system in public areas. It is an amplification setup with an amplifier and loudspeakers, used to reinforce a given sound (e.g.,a person making a speech, prerecorded music, or a live musical performance) so that the audience can hear it clearly. The PA system is controlled from a mixer which blends the incoming signals from microphones and musical instruments, modifies the tone, and controls the overall level of the signal that is sent to the amplifier. The simplest PA systems consist of a microphone, a modestly-powered mixer-amplifier (which incorporates a mixer and an amplifier in a single cabinet) and one or more loudspeakers. Simple PA systems of this type are often used in small venues such as school auditoriums, churches, and small bars. PA systems are also sometimes referred to as "sound reinforcement systems" or simply "sound systems." The term "PA system" also refers to an audio transmission system used in institutional and commercial buildings, in which input from a microphone or prerecorded music is amplified and sent to speakers throughout the building. These types of PA systems are commonly seen in schools (used to read announcements and summon students) and hospitals (used to summon staff or declare states of emergency). Other examples include airports, airplanes, and drive-through windows at fast food chains. Some systems can address specific rooms and exclude others. Other types of PA systems, called intercom systems, also have microphones in each room so that the occupants can reply to the central office.
Public Address systems are configured slightly differently to the normal sound system. They utilise High Impedance (100volt) speaker outputs rather than Low Impedance (4-8ohm). To keep it simple, the amplifier power output (measured in wattage) must exceed the sum of the speaker wattage tappings. The speakers used have a transformer on each that has various wattage tappings to allow matching to amplifier power and volumes required. This configurations allows many speakers to be run from a single amplifier over long cable distances with little signal loss. Bosch Public Address Range Formerly Badged as Phillips The 'Plena' Range of Public Address Mixer-Amplifiers. The PLENA mixer amplifier is a high performance, versatile four microphone inputs mono mixer amplifier, capable of fulfilling a wide variety of public address requirements for surprisingly low cost. A wide choice of input connectors are available: balanced 3-pin XLR and phone jack for microphones, 5-pin DIN for a priority microphone, and stereo RCA for music sources (summed to mono). All microphone inputs have phantom power supply to provide power to condenser microphones and selectable speech filters for improved intelligibility. Microphone inputs 3 and 4 can also be switched to line sensitivity. Furthermore separate music inputs with their own input selector and volume control are available.
The Plena BGM/paging system is the versatile All-in-One solution to cover all needs for background music (BGM), making announcements and paging people. This high performance, yet affordable, unit is very easy to install and operate. This unit has a CD-player that not only plays normal audio CDs but also CD-Rs with MP3-encoded files. It has mono operation in accordance with public address needs and allows for a whole day of high quality uninterrupted music playback from a single MP3-disc. The digitally controlled FM/AM tuner uses a frequency synthesizer for accurate capture of radio stations and has 10 presets for FM and 5 presets for AM to store favourite programs. An auxiliary (music) input and tape output are provided for connecting external equipment like a DVD-player or cassette deck. The announcement part of the unit has 3 balanced microphone inputs. Microphone input 1 has a DIN socket on the rear for a priority microphone (e.g. the DST1) All microphone inputs and the music source have their own volume control, with a shared bass and treble tone control and a shared master volume control. The powerful 120 W output section has two transformer-isolated 100 V constant voltage outputs for driving 100 V loudspeakers in two separate zones. Both zones may be individually selected from the front panel and the output level in each zone can be individually set. Each zone also has a low voltage output for connection to 8 Ohm loudspeakers. A separate 100 V Call Only output is provided for addressing an area where BGM is not required but where priority announcements are. A voltage-free Call Active contact is available for overriding local volume controls during priority calls or other purposes. A LED VU-meter monitors the output.
The PLENA digital message manager stores up to 12 separate messages recorded using the standard Windows® WAV file format. Via any of its 12 trigger inputs, it can replay announcements of up to four messages routed to user-determined zones (in combination with the PLENA system pre-amplifier). Trigger inputs have sequential priority, and are remotely activated, although inputs 7 to 12 also feature front panel activation. Messages are downloaded from a PC into the unit's built-in flash memory via RS232. Audio quality is set by adjusting the sampling rate from 24 kHz (near-CD quality) to 8 kHz (maximum message time of 500 seconds). The message manager functions as a stand-alone unit as the PC is disconnected once messages have been downloaded. The Windows® software (supplied) takes care of downloading messages and configuring and routing of announcements. The unit features built-in system checks and other safety features for providing emergency and evacuation messages in IEC60849-compliant systems.
The Plena BGM source unit is the ideal high quality source for background music (BGM) in public address systems. The unit comprises a CD-player and a digitally controlled FM/AM tuner in a compact 2U-high, 19”- wide housing. The unit can be connected to all types of public address amplifiers. The unit's appearance is in-line with the current range of Plena products. The CD-player not only plays normal audio CDs but also CD-Rs with MP3-encoded files. It has mono operation in accordance with public address needs and allows for a whole day of high quality uninterrupted music play-back from a single MP3-disc. Repeat and random play modes are also provided. The digitally controlled FM/AM tuner uses a frequency synthesizer for accurate capture of radio stations and has 10 presets for FM and 5 presets for AM to store favourite radio stations. Both the CD-player and the tuner operate simultaneously on different outputs to facilitate two-channel BGM distribution. The output level of both outputs can be adjusted via rear panel presets. A combined output is also available for connection to a system without an input selector. The combined output provides the tuner signal as long as the CD-player is not playing. If the CD-player is active, then the CD-player signal is provided on that output.
Plena Power Amplifiers, balanced XLR input and loop through output. Also features a 100v line input that allows for direct input connection of a remote 100v speaker line thereby increasing the locally available power output. LED VU metering and 70v/100v and 8 ohm outputs, 240VAC / 24VDC, 2RUcomes with rack mount brackets. |
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