Voice Alarm Systems are essentially “Life safety systems” for the controlled evacuation of offices, complexes and public buildings by means of the clear transmission of intelligible messages.

These systems constitute a core part of the business of B.L. Acoustics Limited. We can supply systems from a variety of manufacturers from small, stand alone 2 to 32 circuit systems to comprehensive multi-building strategies. We fully design, install and commission several manufacturers equipment which include:
– Zenitel (formerly ASL)
– Ateis
– Baldwin Boxall
– Bosch

We also frequently work on older systems that are no longer supported by manufacturers including:
– Tannoy Audix
– Avalon
– Millbank
– Philips
– Advanced Safety Communications
– SIGnet

We are fully conversant with the latest standards including BS5839 part 8 and EN54 regulations.  We fully support the need for continuous improvement in the area of fire safety equipment.

BLA have many years of experience in this field. We will gladly assist in the alteration or extension of an existing system or indeed with “phasing in” a replacement.

About Voice Alarm Systems

IMAG0446Voice Alarm systems broadcast speech and tones to specific groups of people or individuals across single or multi-zone areas.  The equipment can be part of a Public Address system, offering additional facilities such as paging and background music, or exclusively used for emergency purposes. In either case the Voice Alarm element is often linked to a fire detection system for automatic evacuation and alert in a fire.  Systems are designed to suit a wide variety of sites including:
– Airports, Law Courts, Prisons, Banks
– Shopping Malls, Supermarkets, Stores & Shops
– Universities, Colleges, Schools
– Sports & Leisure facilities
– Convention Centres, Exhibition Halls
– Theatres, Pubs, Clubs, Churches

Our expertise is applied equally to new sites as well as the upgrading of the time honoured and tired installations. As an ISO9001 accredited company our activities are fully documented to ensure quality and workmanship is maintained. Our involvement is total, from establishing initial user requirements and costings through to commissioning and final handover. Expert advice is on hand throughout to provide a flow of information to all relevant parties and trades.

Training and induction courses are offered for the end-user of the equipment and our philosophy is to maintain an on-going relationship with all our clients. Cost effective servicing and maintenance packages can be offered, whether the customer’s requirements are for a yearly or quarterly service call.

Why install a Voice Alarm System?

Voice Alarm Systems cater more effectively than bells or sirens for threat from fire, bomb, chemical hazard or evacuation alert. It is now well known that members of the public pay little heed to sounders but respond well to messages that can relay specific and appropriate information. Research has shown that only 13% of people respond to fire alarm bells in a timely manner.  Installing a voice alarm system increases this to 75% of people.


The mark of a good system is that every word is clearly understood. The meaning in words is carried chiefly in the consonants whereas the vowel sounds communicate tone and depth. Poor systems have plenty of vowel sounds and very few consonants.

Loudness in itself does not make speech intelligible and a poor installation will often sound worse as the volume is turned up. BLA address the issues that affect intelligibility through a combination of experience and computer modelling with results in line with the latest standards.

The process begins with an appreciation of the building acoustics, which have a major influence on clarity. Large areas and reflective surfaces create echo’s and reverberate sound that confuses the ear and reduces understanding. Unless the performance of the building is taken into account, it is impossible to predict the final quality of the sound installation with any accuracy.


touchscreenssMicrophone announcements can suffer from poor diction and from voice fluctuations. The microphones we provide automatically compensate for the excessively loud and excitable voice and the quiet breathless voice. We can offer client training programmes designed to educate users in basic microphone techniques.

A range of stylish control units are provided for Voice Alarm and Public Address applications. They have an intelligent zone recall facility that automatically repeats previous zone selections on subsequent calls. Fully programmable push buttons, each capable of activating a different source and zone with its own level of priority.

We can also provide touchscreen control panels that provide a greater level of control over messaging, audio routing and fault reporting.

Speech Management

Standard messages can be digitally stored and transmitted automatically or manually to the loudspeakers in an emergency or during tests and fire drills. The addition of one or two microphones caters for the ad-hoc situation and fire fighting operations. Messages are tailored specifically to each speech zone and several messages can be activated to alert and evacuate simultaneously.


ceilinglsArchitects are often pre-occupied with the appearance of loudspeakers whilst specifications focus on the basic need for intelligibility.  British standards provide measurable criteria for clarity and we ensure that the right results are achieved in harmony with the building acoustic and interior design.  For voice alarm applications we only supply loudspeakers that are fully compliant to EN54-24.

Fire Protection

An evacuation system must keep working for at least 30 minutes under a fire condition. This means that essential control equipment must be kept away from the immediate fire risk and cabling to microphones and loudspeakers must have fire protection.

Alarm Tones

The best public response is achieved by a mixture of speech and tones. Any sound such as a fire bell or klaxon can be stored on a message card to be interspersed with the spoken word for rapid and effective evacuation. All messages and tones can be repeated, cycled and overridden to fit the series of events that accompany a major hazard.

Fault Monitoring

Malfunction of the system must be identified before a disaster occurs. Our systems flag up any faults immediately and continues working in standby mode under the most severe adversity. This fault monitoring system satisfies the stringent standards of fault warning required by BS5839 for Fire Detection and Alarm Systems.  The equipment we provide is fully compliant to EN54-16.

Failures are indicated on the master chassis and relayed to building management systems and fire detection panels as required. Each controller and power amplifier also has an in-built monitor panel to report faults while the system continues to provide a level of service. By careful deployment of the amplifiers the sound levels and intelligibility can be totally unaffected by any malfunction.

Loudspeakers are wired on independent monitored circuits such that no cable break will cause total loss of audibility.

Standby batteries are distributed within the equipment racks to maintain service during a power failure for in excess of 24 hours.

If you want to know more about Voice Alarm Systems or if you would like a no obligation quote, please contact us.
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