History of Castle Sound and Vibration Products

Castle began its journey in 1971 when the two founders won a tender for the Open University to supply a large quantity of sound indicators. The CS15C was developed and had a dynamic range of 10dB with an overall measurement capability from 60dB to 130dB, so you really needed to know what you were doing and select the right range for the task at hand.

Soon after this came the CS18B which improved the measurement range down to 50dB and had the futuristic addition of a conical nose cone.

The next major development for the company, which saw appearances on Tomorrow’s World and many local and regional TV and radio shows was the invention of the Electronic Orange with its iconic ‘lighthouse’ unit, which followed the music. The Orange was designed to cut power to PA systems when noise levels were exceeded, as a method of noise abatement that could be prescribed by Local Authorities. This product remains in the fleet today albeit after several re-developments.

The mid- to late-1970’s brought about flares, inappropriate staff advertisements and numerous developments in the Castle sound meter range including Octave and Third Octave Band filter units that could be bolted to the bottom of the sound meter as well as alternate brands including Pulsar, which was a US company purchased to expand into that market, and Cirrus! There was also an OEM drive with many versions produced for France, Sweden, Canada, South Africa the USA, and several UK companies. This period also saw chart recorders introduced to allow the sound level to be recorded for later review and in 1978, the first ‘tube’ style acoustic calibrator, copied and used the world over for decades afterwards.

In 1981 the prefix was changed from CA, CS and others to GA (General Acoustics) to make for a uniform approach and this prefix is still used today for new products.

A new and improved Electronic Orange was introduced in 1982 along with a new cast aluminium alloy casing for the sound meters, which went on to be used for several decades. The first product in the futuristic looking body was the GA103, which was the first Castle product to give a measure of the Leq directly on the display. This was followed by the GA102, GA202, GA104 and GA204, still with analogue needle displays, but with larger dynamic ranges and enhanced features.

As a complete aside, in 1985, the Banana Interface was brought to market by Castle having been invented by two local schoolteachers. This creative product allowed a BBC computer to operate a series of relay switches that could then be used to control external devices such as motors, lights and servos. Many school children across the country at that time were able to build models that could be controlled by computer programmes teaching valuable skills in information and control technology.

Between 1986 and 1989, there were numerous significant developments starting with the first personal dosemeter (GA253), the first meters with in-built Octave Bands (GA107) and the first digital display meter (GA108), which also had an analogue needle so at the time, represented the ‘best of both worlds’.

With the 1990’s came plastic injection moulding in the guise of the ‘Pocket Meter’ range, which fulfilled the role of both a sound meter and a dosemeter and there was even a version that converted between the two (GA110 and GA111). These new small meters were micro-processor based and menu-driven with membrane keypads replacing physical buttons. They also came with the ability to calculate several parameters simultaneously – a significant advancement in applications such as Noise at Work assessment.

1991 was also significant because of the introduction of the GA801 vehicle noise meter, many hundreds of which were sold all around the world for testing the sound coming from car and motorbike exhausts at the roadside. Several police forces, notably in Sweden used this product to enforce noise levels and issue fines.

The next major product line from Castle came in 1994 with the professional range, which still used the cast alloy casing, but replaced the needle display with a digital one and adopted the membrane keypad for easier use of the menu system. The professional range served the company very well for almost a decade and offered occupational and environmental measurements and was one of the earliest products to be packaged in a weatherproof housing for extended use outdoors.

The Occupational versions of the professional range also had a very innovative feature as they included data on hearing protection, which could be directly compared with measurements on the screen. This is a feature still unique to Castle Sound Meters to this day.

Hand Arm Vibration assessment and control became an HSE focus in the early 1990’s, so Castle set about to develop a user-friendly product, the likes of which did not exist at the time. This resulted in the GA2001 in 1997, which although a little cumbersome by today’s standards, soon became a market leading solution and set Castle up as one of the top providers of vibration products in the UK.

As technology moved on, the old alloy case became a limiting factor, so a new injection mould tool was designed and resulted in the Vocis sound meter in 2003. This product had parallel octave and third octave band measurement, large memory, occupational and environmental measurement, hearing protection database and was incredibly easy to use compared to many other leading brands.

This new casing allowed for the vibration offer to be updated, which saw the introduction of the Excieo and again, this swept the market because of its intuitive user interface, large dynamic range and novel system for attaching the accelerometer to a tool. It was also the first Castle meter to have Whole Body vibration measurement capability. The Vocis and Excio alongside an updated pocket meter in the original plastic body, lasted for well for over a decade before market expectations, component availability and advancing technology forced the need for radical change.

The first novel product was the Vexo, released in 2012. This was a dedicated hand arm vibration meter, which did nothing else and as a result was so simple to use it became a massive hit and still sells in great numbers to press, albeit following a few updates along the way.

We now come to the modern range of instruments, which began in 2016 with a slimmed down and updated plastic casing and the first in-built Wi-Fi product – the dBAir. Now with a colour display, even bigger memory, Wi-Fi and a plethora of new features, this catapulted the company into the 21st century. Now complimented by the SONIK simplified sound meter, the VibA(8) vibration meter and an updated SONUS sound meter range in the old ‘pocket meter’ body, this has produced a significant breadth of offer for a modern market.

The most recent developments have been the dBCal in 2019, a 3-level acoustic calibrator with wireless communication and atmospheric compensation built in and finally the dBAngel in 2021, which is a dedicated outdoor monitor with 4G, solar power and large enough batteries to keep the whole system running continuously.

As to the future, with significant development activity in the pipeline in many areas, you’ll just have to watch this space!

Timeline