The Classic SoundSign

The iconic SoundSign from Cirrus Research is an easy-to-install noise-activated warning sign that can be used in environments where there is a need to clearly warn or indicate when a preset noise level has been reached and/or exceeded.

The SoundSign uses bright LEDs to display a message when the noise level you select has been breached; the level can range from 40dB(A) to 114dB(A). The SoundSign is absolutely perfect for environments such as factories and workshops as it can serve as a visual alert or reminder for your staff to wear their hearing protection. It's also great for quiet environments like schools, hospitals and libraries as it will act as a silent reminder for people to keep the noise levels down.

Available in four distinct designs and in multiple languages, the SoundSign can be used in any environment, almost anywhere in the world. Along with noise measurement equipment, the SoundSign is the perfect way to help you control noise levels in the workplace, thereby compling with health and safety legislation.

The Data Logging SoundSign

The SoundSign is also available as a data logging unit. The plug-in USB noise data logger plugs directly into the SoundSign, recording and storing noise data over longer periods of time. This data can be downloaded onto your PC and imported into a spreadsheet, where you can see the date and time of the noise levels recorded by the SoundSign.

The Covid-Secure SoundSign

The Covid-Secure SoundSign from Cirrus Research has been designed to help businesses and organisations mitigate the new risks associated with excessive noise levels, in the wake of the Coronavirus pandemic. Experts suggest that the louder an environment is, the more likely it is for people to raise their voices, which increases the risk of virus transmission. The Covid-Secure SoundSign works in exactly the same way as our other noise-activated warning signs, but features a new design that will alert staff and visitors to high noise levels, encouraging them to keep the volume down to reduce the risk of spreading the virus. The Covid-Secure SoundSign is particularly effective in the hospitality industry, where people are not mandated to wear face coverings. A basic sound level meter can be used in conjunction with the Covid-Secure SoundSign to help monitor noise levels.

  • Display a clear warning when a preset noise level is exceeded
  • Trigger level from 40dB(A) to 114dB(A) for use in any environment
  • High intensity white LED technology for high visual impact and a long operating life
  • Five standard designs to cover all applications, including a Covid-Secure variant
  • Remote units to extend visible coverage
  • Available in different languages
  • Quick and simple to install
  • Designed and manufactured in the UK by Cirrus Research
Supplied accessories
  • 10 inter-connection cable to master unit
  • 5m power extension cable
Optional accessories
  • USB data logger and CD
  • SoundSign alert beacon
  • 10m inter-connection cable for SoundSign units
  • 2m microphone extension cable for SoundSign master unit, for use with MV:200C and MK:215
  • 5m microphone extension cable for SoundSign master unit, for use with MV:200c and MK:215
  • 10m microphone extension cable for SoundSign master unit, for use with MV:200c and MK215
  • Mains power supply for CR:201 SoundSign master unit
  • Premaplifier
  • Microphone capsule
  • Factories and workshops
  • Indoor worksites
  • Libraries
  • Schools
  • Hospitals
  • Call centres
  • Pubs, bars and nightclubs


Noise-activated warning sign

Trigger level

40dB(A) to 114dB(A) in 1dB steps



Frequency weighting

A weighting to IEC 61672-1:2002

Time weighting

Slow to IEC 61672-1:2002

Visual indication

High-intensity white LED with four standard designs

User-selectable brightness levels

Display delay time

None or 30 seconds

External power

2.1mm power jack

12v DC via CU:200 mains power supply

Output connector

Control for remote display units via standard 2.1mm power jack

Up to three remote display nits can be powered from a master unit


12" diameter, 2" depth


1.3lbs (0.6kg)


2 x keyhole mounting slots

Data logging

CR:203 USB data logger with 32,000 samples of LAS

(Slow A weighted sound level)

User-selectable 1 second (9 hours), 10 seconds (3.7 days)

1 minute (22 days) sampling

Case Studies

Product Datasheets

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The SoundSign in action

The SoundsSign is perfect for use in noisy environments such as factories, workshops, and pubs, nightclubs and bars, to warn employees when noise levels become too high and to indicate when the hearing protection you have supplied them with, must be worn.

When a noise survey or risk assessment has been made using a sound level meter (like the Optimus+ Red) or a noise dosimeter (like the doseBadge5), areas may be found where hearing protection must be worn or where high noise levels will occur throughout a standard working day. It may not be practical for employees to wear hearing protection constantly, especially where high noise levels are intermittent or where they vary significantly during the course of the day. The SoundSign that displays the message Hearing Protection Must Be Worn can be used to show when an employee must wear their PPE. Where hearing protection is not required but there is still a need to indicate when noise levels are high, the SoundSign that displays the message Warning High Noise Levels can be used.

If it is essential for anyone entering these areas to already be wearing hearing protection, the SoundSign Remote Unit (CR:202) can be connected to a master unit and positioned outside of the work area (next to an entrance or door for example); this will ensure that anyone entering the room will see the visual alert and ensure they are wearing the correct PPE upon entry.

The CR:203 SoundSign Data Logger can be added to your SoundSign setup, in order to gather a record of when noise levels breached your preset level, and also to help monitor the effectiveness of the hearing protection you have in place.

We all know how loud pubs, bars, nightclubs and live music venues can get - it's what creates the atmosphere! However, despite loud music and chatter being what makes these sorts of places great, as an employer, it still your responsibility to ensure that your staff are protected from excessive noise. The SoundSign is absolutely perfect for these sorts of environments.

Lightweight and simple to use, the SoundSign can be used for temporary venues (such as music festivals) as well as for permanent installation. In music colleges and schools, the SoundSign can help to educate students as well as staff about the risks of noise exposure.

Using either of the two variants of the SoundSign that display "quiet" messages can be an affective method of ensuring that low-noise environments such as hospitals and healthcare facilities remain quiet.

It's commonly understood that noise is the primary cause of sleep deprivation and disturbance amongst hospital patients and a recent study has shown that noise levels are getting worse. Keeping an eye on noise levels can help improve someone's recovery process and can help to create a calm and peaceful working environment for healthcare staff.

With the SoundSign in place throughout hospitals and healthcare facilities, patients, staff and visitors can be alerted to when noise levels are above an acceptable level, encouraging them to lower the noise.

There have been many studies that have shown that high noise levels in classrooms has a negative impact on both teacher and students. Whilst it's commonly accepted that schools and colleges are going to be noisy environments, it's still important to ensure that all practical steps are taken to try and reduce the impact noise has not only children's learning, but also their health and that of their teachers.

Many buildings that are used for educational purposes were not designed with noise in mind, with hard walls and floors being an acoustic nightmare! The SoundSign can be used to show students and staff when noise levels are approaching unsafe levels and will help health and safety managers within schools and colleges to identify noise "hot spots".

The SoundSign can also be used in classrooms, corridors and halls when examinations are taking place to help maintain a quiet environment.

The Covid-19 pandemic has presented a whole host of new challenges for businesses and organsations across the world. The Covid-Secure SoundSign has been designed to help mitigate some of the risks involved with returning to work and operating safely.

High noise levels in an environment such as an office or bar/restaurant will increase the likelihood of people raising their voices or shouting to be heard. Experts suggest that shouting, the risk of virus transmission increases as it's more likely that saliva containing the virus will be spread. The Covid-Secure SoundSign will provide a visiual alert when noise levels are reaching potentially risky levels, which will prompt both staff and visitors to try and reduce the volume.

The Covid-Secure SoundSign is perfect for offices, bars, restaurants, pubs, clubs and other indoors environments where mask-wearing is not mandated. A basic sound level meter can be used in conjunction with the Covid-Secure SoundSign to help monitor noise levels.

SoundSign remote display units

The Sound Sign is also available as a Remote Display Unit which is controlled by a Master Sound Sign. When the SoundSign lights up, the Remote Units light up in the same way and for the same period of time.

The Remote Display Units are connected by a simple cable to the Master and up to three units can be daisy-chained together so that a wide area can be covered.

Remote units are ideal in applications where the main unit cannot be seen. For example, in a factory where the main SoundSign is out of view of employees, a remote unit can be installed to ensure that sufficient coverage of the noise warnings is available.

Another common use for the remote units is to position one at the entrance to a high noise level environment. This can help to ensure that anyone entering this environment is aware of the need to wear hearing protection or is aware of the risk of high noise levels.

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