Public address, conference and interpretation systems

Sound and public address systems (PA) are required in locations where large groups of people need to be addressed with messages.

PA is used in shopping malls, hotels, airports, trainstations, bus terminals, office buildings, spas, gyms etc. A PA system is usually limited to perimeter of one complex or building, divided into different functional areas aka „zones“. For example, hotel’s lobby and spa are different zones, where transmission of different program is required.

PA systems transmit both background music and speech. It is possible to transmit pre-recorded advertisment or information messages or read messages directly into into microphone.

EVAC
To improve public safety, requirements to implement EVAC-standard compliant PA system in public buildings is increasing. EVAC PA system functions similarly to ordinary PA system but components and design must comply to EVAC standard. EVAC PA systems transmit fire-alarm-initiated pre-recorded evacuation messages. The system monitors its own health also when no messages are transmitted. This functions ensures that the system is operational anytime when urgent need for use occurs.
Components of PA systems

Microphones
Announcing microphones used in PA systems enable zone selection directly from microphone

Sources of signal

Most common signal sources are FM radio and MP3 compliant CD player, which enables longer unique music reproduction.
Automatic announcement devices
This special device with digital memory will play pre-recorded message right after activated by external source. E.g, message can be: „Dear visitors, we have an emergency. Please leave the building immediately“.

System amplifiers
Signals from sources of sound (radio, CD, microphone) are amplified to appropriate levels to ensure optimum reception. In simpler solutions analogue amplifiers are used, in larger complicated installations mainly digital amplifiers are installed.

Loudspeakers
As the main purpose of PA system is clear and understandable transmission of messages, PA speakers frequency response range is limited to transmitting best human voice. Therefore hi-fi audio experience is not delivered via PA speakers.

Conference and congress systems are necessary in meetings where votings are carried out. Main users of these systems are parliaments, international organizations, city councils, conference centers.
Congress system = conference system + additional functionality:

  • Voting possiblity – each participant from his seat
  • Identification of participants – voting eligibility and other settings are identified by ID-card or similar technology from seat right before voting.
  • Sending of text messages to participants – right to seat to participant microphone’s LCD stand for receipt of text messages, choices for gallup voting etc.
  • Addressing the microphones – each microphone is given address to enable dome camera control (camera is turned to speaker when his/her microphone is activated). Based on address, the word is presented to speakers based on official program of the conference.
  • Displaying order of speech and voting results on TV or screens via projector.

The above listed functions are combined in digital conference and congress system DCN.
Conference systems are special sound transmission systems that are used in meetings with large number of participants or where following formal reglement is of high importance. Main users of these systems are conference centers, hotels, boards of companies, courts of law, training centers.


The benefits for participants when using conference system:

  • Each participant has clear reproduction of other speakers’ speech and possibility to speak from seat
  • Meeting organizer can enforce meeting reglement and mute speakers
  • Use of microphone increase meeting efficiency via „on air“ effect
  • Noiseless and echo-free direct sound
  • Possibility to add recording solution
  • Special software to generate digital protocol

Interpretation systems are required when meeting is held in several languages that all participants do not speak. Interpretation systems are used in international conferences, symposiums, trainings etc.

System operating principles:

  • Translators are located in sound-isolated booths and spoken language reaches them via headphones
  • Translator has special microphone with LCD display where specific language channels and other settings can be set
  • Translation reaches delegates via wireless infra-red transmission system, where each person holds personal IR receiver. The delegate can choose language channel from receiver. The wireless system enables delegates to move around without losing part of the message.

Another option to listen translation is via conference system. In this configuration chairman and delegate modules have headphone and channel module with headphone connector and choice of channel. Benefits of wired interpretation are noise-free sound, also there are no need to store, charge and maintain IR receivers.

References