Audio + Design (Also known as Audio & Design, or Audio and Design, or Audio Design Recording- hf. ADR) is a British firm that was responsible for the first FET-based limiter. Their ‘Vocal Stressor’ dynamics processor has long been rumored to be the the kit limiter used on many Led Zeppelin recordings. For readers who have not spent much time in recording studios: John Bonham’s drum sound on the Zeppelin records is still, 40 years later, regarded as a benchmark of rock drum sound, by both drummers and producers/engineers. And by rock-music fans in general. A lot of time gets spent daily in recording studios around the world trying to ‘get that Bonham sound.’ So this rumor is somewhat significant.
Other well-known users of the ADR compressors include Mike Chapman, producer of The Sweet and about a million other seminal 70’s groups.
Anyhow. The unit featured at the head of this post is module from ADR’s ‘Scamp’ line of plug-in modular audio processing equipment. From what I have been able to tell, various units in the Scamp line were available between at least 1976 and 1984. Modular racks of audio processing equipment were very popular during this period. The concept is a good one: users can purchase a single rack-case with slots that accept the manufacturer’s modules. The Rack-Case has a built-in power supply which provides the voltage(s) that the units need in order to operate. In this way, a single chassis/powersupply can support up to 17 pieces of processing gear, rather than each little compressor, EQ, etc., each having their own. Since the current draw of these items is so low, it makes a lot of sense. It saves a lot of space in the studio, and it saves money.
Of the other contemporary manufacturers of modular processing set-ups, The DBX 900 series is perhaps the most widely-seen. Valley People, Aphex and API also made these types of product lines. The API 500 series has survived, and in fact become a contemporary standard in recording studios, with dozens of independent firms currently making a huge variety of processing units to fit the API-500 spec frame/voltage. I have a DBX 900 rack and an API 500 rack, and they are some of my most-often used pieces in the studio.
There is a lot of documentation on the web regarding the DBX 900 series and the API 500 line. The ADR Scamp line-up is not as well-represented. Click on the link below to download 18-pages of 1976-1984 SCAMP paper.
DOWNLOAD:
