What is the requirement?

Legislation in the areas of health and safety at work and noise pollution may mean that you should consider introducing devices to limit sound levels either in the workplace, or from public performances in your premises (particularly where an entertainment license applies. In some instances sound limiting may be required by the Environmental Health Officer, who may define the levels at which sound may be limited and may wish to inspect any installation to ensure conformity.

What do limiters do?

Sound limiters are devices that are designed to monitor the sound in an area and limit the maximum sound level that can be generated by sound equipment such as used by discos or bands etc. The device is installed into the signal path, or the electrical supply to the equipment in the area and applies control to prohibit the sound from exceeding the preset level. Some devices simply cut the power when the level is exceeded, whilst other devices can clamp the sound at a fixed level by reducing the mains voltage to the equipment or signal to the amplifier.

Knight Sound and Light Solutions

We are fitting a range of devices into such areas as Licensed bars, Church halls, clubs, hotels etc. The devices we fit are approved by local council/Government. We can provide plans and estimates for your premises. We offer solutions based on equipment from three main manufactures, Sound, but can also offer equipment from other manufacturers if required.

Authorisations and Training

Due our extensive knowledge and experience of installing sound limiters, we are the approved installer for many local authorities. As part of the working relationship with these local authorities, we have helped to train their officers on our premises as required.

Budget Range

If you need sound level control to meet regulations and are on a limited budget. Then, for infrequent usage (eg weekends only), this may be the optimum solution for you.

G990 Noise Pollution Control System

G990 Noise Pollution Control System

This unit continually monitors the sound level and will disconnect the mains supply when the preset level is exceeded. An indication of the sound level is given on the front panel by Green, Amber and Red LEDs. Green indicates level ok, amber that the threshold is being approached and red that the level has been exceeded. The mains supply to be used for the sound equipment is wired through contractors which are built into the unit. The preset level is adjusted during installation to meet the required limit. Once the level has been exceeded, the mains is not restored until after a reset period. This period is also preset during installation. The unit can be used for single phase or 3-phase supply. Sound level is monitored by a remote microphone which is discretely housed on a surface of flush mounted wall box.



Remote LED Display

Remote Indicator display, fits standard mains socket backbox. LEDs replicate main panel display with 7 green, 7 Amber and 7 red High Intensity LEDs.


Mixer Interface

Instead of interrupting the mains supply, this interface provides control of the audio signal between the mixer and the amplifier, reducing the signal level to prohibit the sound exceeding the limit.


SL2000 Noise Pollution Control System

SL2000 Noise Pollution Control System

This unit has 4 key selectable sound levels. It incorporates a 30Amp contact breaker and a built in fire alarm interface. Sound level monitoring is by use of a sound pick-up microphone (supplied).



Remote Indicator Display

This display can be used to indicate noise levels to performers on stage or DJs. Green Lamp indicates level ok, 1st Amber that level is approaching the limit, 2nd amber that sound is close to the limit and Red that limit has been exceeded and sound has bee cut off by the controller.

Professional Range



This range of equipment is suitable for installations where frequent use is likely such as installed function rooms, music venues etc.


Formula Sound Sentry MK2

Sentry Mk2 Main Unit

The Sentry is a versatile unit and incorporates a number of internally selectable options. It can work in conjunction with a relay or contractor and usually controls mains power. But the Sentry can control any device that can be controlled by a relay or switch eg disconnecting loudspeakers, switching passive attenuators etc. The unit has a built in microphone which reduces the opportunity for tampering. Two preset thresholds may be configured so that they can be selected by a remote switch or timer to allow the unit to operate at two different levels (eg. at different times of the day.) There is a red to green colour bar which indicates the volume level in the venue. The red section increases in size to aid viewing. The green section indicates level ok. The level may occasionally peak into the red without concern but if it continues to exceed the limit (indicated by the 3 red segments), the unit will trip and has to be manually reset. A remote reset switch is available. In addition there is provision to connect a security which could be used to detect open doors or windows that would impair the sound proofing of a building, etc.


Formula Sound AVC2


The AVC2 limits sound level by controlling the audio signal on the sound system. Whilst the sound level is below the preset threshold, the AVC2 has no effect. But if threshold is reached, the unit fades the signal level in a way that is almost undetectable. The amount of signal reduction being applied is indicated by the LED bar graph meter on the front panel of the unit. The more the signal is increased, the more fading will be applied by the AVC2. If attenuation reaches its maximum, the output level will be reduced by more than the increase in input level so that the effect becomes noticable. A clip indicator is provided to show when the input stage of the AVC2 is being over driven. Reducing the input level will gently release the attenuation being applied by the AVC2.

Specialist Range - Master Audio



If you have specialist requirements demanding rigid control parameters then this range of controllers may offer a solution for you.


Master Audio SSL1

Master Audio - SSL1

Stereo Sound Limiter - ideally suited for permanent installations where the unit can be installed in the equipment signal path. The unit includes LED bargraph displays of the input levels of each of the stereo channels. If the signal level enters the red (+7) portion frequently or for a sustained length of time, then the limiter will operate to limit the signal to a preset level. The overload indicator is then lit. Limiter control is carried out independantly for the left and right channels. A bypass switch allows the limiter function to be disabled for special occassions. A sliding door conceals the level preset and the bypass switch and these may be secured with a tamper proof seal. The SSL1 also includes selectable LF filters for each channel, and has balanced input/output connections.


Master Audio TSL

Master Audio - Timetable Sound Limiter - TSL

This unit operates by controlling the signal between the mixer and amplifier. It has an internal clock/timer to enable it to be programmed on a weekly timetable. For each day of the week, the timer can be set for each of four options: DAY NIGHT MUTE and BYPASS. In addition, up to 10 special dates can be entered as BYPASS. If the preset level for the currently active time period is exceeded for more than the preset period, the signal will be muted. An external monitoring unit provides the DJ/Sound system operator with a visible indication when the limit is being reached. As for the SSL access to all preset controls is via sealable sliding doors. The unit monitors the sound level by an external microphone and as well as responding to excessive sound level, it will also respond to abnormal levels caused for example by obscuring or disconnecting the microphone.