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Public Address - Guide

'Tannoy' Origins

'Tannoy' - There are very few products and inventions that impact to our lives so strongly that their name becomes synonymous with the function they perform. 'Tannoy' is one such product that immediately identifies against the speaker and audio function it performs. In fact, the term 'Tannoy', is widely recognised colloquially and generically to describe a Public Address (PA) system.
As one of the oldest (and most recognisable) audio brands in the world, Tannoy, is a UK company (based in Scotland), manufacturing speakers and Public Address (PA) systems. The company was founded as Tulsemere Manufacturing Company in London in 1926. Tannoy made its name during and shortly after World War II, supplying PA systems to the armed forces and then to holiday camps such as Butlins and Pontins.

Public Address (PA)

Public Address or 'PA' is generic term, essentially describing an audio / sound based electronic amplification system, that is typically used to communicate and broadcast voice audio messages.

Whilst understanding this generic basis, it is because of the different PA market applications, that there is often confusion and sometimes disagreement in describing PA systems. For example, we often observe the term 'PA' being used interchangeably to describe an audio solution providing function against different foreground and background audio applications. Both function similarly, but employ quite different technologies and products - it is therfore important to distinguish the two by function, system design, and capability.

Abletek product sales and installation services are focused towards 'installed', high impedance, 100v, commercial audio solutions. We use the terms PA and 'Tannoy' interchangeably to describe commercial voice announcement systems, function, application and products.

How does a Public Address (PA) system work?

Small, basic Public Address (PA) systems (eg. a small school or library) employ three basic components: a microphone, amplifier and loudspeaker/s. The microphone is the audio source; in use, it simply 'keys' or controls the amplifier as well as providing the system audio input. The amplifier provides basis of power output and delivery to the loudspeakers, which in turn re-create the audio output to the coverage local area/s.

Microphone (audio input source) Amplifier (power) Loudspeakers (audio output)

Most PA systems employ the same basic system components as described above. However, many employ some additions that allow for larger, flexible and more integrated solutions. The following are some examples of PA components that are regularly used within such systems:

Multi Output / Zone Amplifiers: Selectively allow the larger PA systems to output to single/multi or all local areas (eg. you may want office pages/calls to reach the offices only, and not in the factory / site wide.

Audio 'Mixer': An electronic device for combining two or more audio signals. Mixers can be analogue or digital, but perform the same function of producing a summed audio output signal. Mixers and Mixing Desks (also known as audio boards) form one of the main components within many PA systems.

Audio Sources / Inputs: Announcements through demand based microphone use is one of many possible audio source inputs. Many PA systems connect other audio sources such as a background music (BGM) application: music (cd player) or perhaps the radio (tuner).

Integrated Inputs: Found commonly in commercial and industrial environments, we can integrate the PA system to a telephone system (PABX). Many commercial telephone systems perform a function known as 'paging' this allows us to connect the PABX to the PA system (normally the amplifier), and use telephone handsets to 'key' the amplifier. Many organisations elect not to use dedicated microphones, but use telephone handsets to make their 'Tannoy' calls and announcements in this way.

Alarm, Fire and EVAC: Generated under 'alarm' conditions, pre-recorded announcements can be made through the PA system - providing details and evacuation procedure information. It is important to follow recognised policy and standards with these types of systems (eg. BS EN54, BS5839, BS5588 & BE EN 60849). Click for more details about Voice Alarm (VA) / EVAC.

Public Address over IP (IP PA or IP Tannoy): It is now possible to design, configure and manage PA systems to integrate with an IP based network. IP PA 'transports' audio streams from input source (this could be an IP microphone or a music playlist on a server) to output devices (IP speakers) via the same network. To achieve this, IP PA employs two primary components. 1 - audio codecs (en-coders and de-coders) to transition to/from standard electrical audio and IP audio and 2 - network interface/s to connect and interface products to the IP network. Click for more about IP PA and IP Tannoy.