Audio & Design (Recording) Ltd
Encyclopedia
Audio & Design Ltd are an English based company who specialised in the development and production of professional audio processors, in the form of limiters, compressors, expanders & equalisers. The company were one of the first to introduce Field-effect transistor
s into a commercially available limiter amplifier
in 1966. Audio & Design (Recording) equipment has been widely used by professional studios, music artists and the broadcasting industry throughout the world. Recently the company has installed and serviced the BBC World Service
's multi Terabyte
archive installation using Storage area network
technology (SAN).
and a 'noise reducing' expander/gate. All of these parts could be used separately or together for well controlled sound limiting. This combination came about from client feedback. From the feedback ADR designed and built the first units, these were labelled as F760X-RS (RS meaning rackmount stereo
). Later modifications were made and another version was released with a better, ergonomically designed, front panel. This later model was labelled as the 'Compex'.
The 'Compex' limiter provided peak limiting with a multi-ratio, variable threshold compressor. Ratio settings ranged from 1:1 to 20:1 and there were controls for threshold and release time. The inclusion of an expander/gate provided attenuation of the gain during pauses in the audio signal to reduce noise caused by compression; the expander/gate could also be used for special 'punchy' effects, favoured on drum and percussive sounds. Noise gates were often criticised at the time for 'hunting' around the threshold point. The 'Compex' used clever hysteresis
around the gate, this was important to stop unpredictable opening and closing of the gate; the open threshold was higher than the close threshold.
The gain reduction controlled by the 'Compex' was monitored from two meters located to the right of the front panel. There were two light indicators; a red light lit when the signal level reached its peak, and when in expand mode a green light was lit. There were a set of lights for each channel, depending if the unit was the stereo or mono version.
There were some different models of the 'Compex' available; one of these included a smaller console module named the F760-N. This version was built without the expander/gate, it later had an expander/gate added and was then known as the F760X-N.
There is also a rare version called F760X-RS/T. One of the visible differences are the VU-meters, which got the brand"Audio & Design Recording LTD." and if you look on the rear, there you can see the type.
The "T" stands for transformer, which are said to add harmonics to the sound.The "T" version was mainly used in broadcasting stations, mainly because of its SNR and headroom. ADR also built an F760 version for the Helios mixing consoles.
Below is a list of the modules that were available.
Field-effect transistor
The field-effect transistor is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel of one type of charge carrier in a semiconductor material. FETs are sometimes called unipolar transistors to contrast their single-carrier-type operation with...
s into a commercially available limiter amplifier
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...
in 1966. Audio & Design (Recording) equipment has been widely used by professional studios, music artists and the broadcasting industry throughout the world. Recently the company has installed and serviced the BBC World Service
BBC World Service
The BBC World Service is the world's largest international broadcaster, broadcasting in 27 languages to many parts of the world via analogue and digital shortwave, internet streaming and podcasting, satellite, FM and MW relays...
's multi Terabyte
Terabyte
The terabyte is a multiple of the unit byte for digital information. The prefix tera means 1012 in the International System of Units , and therefore 1 terabyte is , or 1 trillion bytes, or 1000 gigabytes. 1 terabyte in binary prefixes is 0.9095 tebibytes, or 931.32 gibibytes...
archive installation using Storage area network
Storage area network
A storage area network is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to make storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices...
technology (SAN).
F760X-RS 'Compex' Limiter
The F760X 'Compex' limiter was made up of three main parts; a compressor, limiterLimiter
In electronics, a limiter is a circuit that allows signals below a specified input power to pass unaffected while attenuating the peaks of stronger signals that exceed this input power....
and a 'noise reducing' expander/gate. All of these parts could be used separately or together for well controlled sound limiting. This combination came about from client feedback. From the feedback ADR designed and built the first units, these were labelled as F760X-RS (RS meaning rackmount stereo
STEREO
STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...
). Later modifications were made and another version was released with a better, ergonomically designed, front panel. This later model was labelled as the 'Compex'.
The 'Compex' limiter provided peak limiting with a multi-ratio, variable threshold compressor. Ratio settings ranged from 1:1 to 20:1 and there were controls for threshold and release time. The inclusion of an expander/gate provided attenuation of the gain during pauses in the audio signal to reduce noise caused by compression; the expander/gate could also be used for special 'punchy' effects, favoured on drum and percussive sounds. Noise gates were often criticised at the time for 'hunting' around the threshold point. The 'Compex' used clever hysteresis
Hysteresis
Hysteresis is the dependence of a system not just on its current environment but also on its past. This dependence arises because the system can be in more than one internal state. To predict its future evolution, either its internal state or its history must be known. If a given input alternately...
around the gate, this was important to stop unpredictable opening and closing of the gate; the open threshold was higher than the close threshold.
The gain reduction controlled by the 'Compex' was monitored from two meters located to the right of the front panel. There were two light indicators; a red light lit when the signal level reached its peak, and when in expand mode a green light was lit. There were a set of lights for each channel, depending if the unit was the stereo or mono version.
There were some different models of the 'Compex' available; one of these included a smaller console module named the F760-N. This version was built without the expander/gate, it later had an expander/gate added and was then known as the F760X-N.
There is also a rare version called F760X-RS/T. One of the visible differences are the VU-meters, which got the brand"Audio & Design Recording LTD." and if you look on the rear, there you can see the type.
The "T" stands for transformer, which are said to add harmonics to the sound.The "T" version was mainly used in broadcasting stations, mainly because of its SNR and headroom. ADR also built an F760 version for the Helios mixing consoles.
Scamp Rack
Scamp stood for (Standardised Compatible Audio Modular Package). The system embodied the card-module concept within a standard racking frame. Although employing no specifically new techniques the design offered dramatic savings in packaging costs without degradation in performance standard. The rack was designed to be configured to different types of recording sessions using different types of modules. The rack could hold seventeen one inch modules all powered from the rack itself by use of an external power supply.Below is a list of the modules that were available.
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