Solid State Logic was founded in 1969 by engineer Colin Sanders CBE, originally to build solid state switching systems for pipe organs. Sanders coined the phrase “Solid State Logic” to describe these electronic control systems, and the name soon became attached to the company itself. As his interest in recording grew, he built Acorn Studios in the village of Stonesfield in Oxfordshire, where he lived, and began designing his own mixing consoles to meet the needs of that studio. By 1976 he had completed the first SL 4000 A Series console, a large format analogue desk with innovative routing ideas; only two A Series consoles were built and sold, but they marked the beginning of the product line that would define SSL’s reputation over the next two decades.
Sanders was never satisfied to leave a design alone, and the A Series was rapidly reworked into the SL 4000 B Series. The first B Series console was completed in 1976, and a total of six were built over a production run of around four years. Technically, the B Series was highly advanced for its time. It combined an in line recording console layout with an onboard computer that provided moving fader automation and programmable tape transport auto location, allowing engineers to store and recall complex fader moves and locate tape machines to precise points in a song. Early customers included Abbey Road Studios in London, Le Studio in Morin Heights, Canada, Kendun Recorders in Burbank, and Virgin’s Townhouse Studios in London, which helped establish SSL as a serious console manufacturer in major commercial rooms.
One of the most famous episodes in the history of the SL 4000 B took place at Townhouse Studios, where engineer Hugh Padgham and producer Steve Lillywhite were recording Peter Gabriel’s self titled 1980 album. The B Series featured a “Listen Mic” reverse talkback circuit, intended simply to allow musicians in the live room to communicate with the control room via a single overhead microphone. To deal with unpredictable levels from musicians at different positions in the room, SSL designed the Listen Mic path with heavy compression and gating.
When Padgham opened the Listen Mic while Phil Collins was playing drums, the result was an explosive, highly compressed and tightly gated drum ambience that had never been heard before. Padgham and Lillywhite were so taken with the sound that they had the console modified to route the Listen Mic output to tape, using it on Gabriel’s track Intruder and later on Collins’s own single In the Air Tonight. The gated reverb drum sound that emerged from this accident became a defining production signature of the 1980s, and SSL subsequently revised later consoles so that the Listen Mic compressor could be recorded without modification.
The real breakthrough for SSL came with the introduction of the SL 4000 E Series in 1979. The 4000 E was conceived as a complete studio control centre, combining the functions of a traditional mixing console with centralised signal processing control, machine control, computer based fader automation and a powerful recall system. SSL’s Total Recall allowed engineers to save the positions of all rotary controls on the console to a 5¼ inch floppy disk and later restore a mix by following a colour coded on screen guide that showed which controls needed to be moved. This significantly reduced the time and guesswork involved in returning to a complex mix and was one of the key reasons the 4000 E became so attractive to busy commercial studios.
Sonically and technically, the SL 4000 E introduced a number of innovations that would define the modern SSL sound. Each channel strip carried a dedicated dynamics section with compressor and gate or expander, along with a four band parametric equaliser. SSL offered several EQ cards during the life of the E Series, but the most famous is the “Black Knob” E242 EQ, developed with the involvement of producer George Martin for AIR Studios. This circuit provided up to 18 dB of cut or boost with tighter control of the low frequencies than earlier SSL equalisers and helped give the 4000 its distinctively assertive and musical tone. Crucially, the 4000 E also included a VCA based stereo bus compressor in the centre section, which quickly became a favourite for adding cohesion and punch to entire mixes.
The combination of in line architecture, flexible routing, a dynamics section and parametric EQ on every channel, along with Total Recall and VCA automation, made the SL 4000 E Series extremely attractive to large studios that needed to work quickly across multiple projects. SSL 4000 E consoles were widely adopted throughout the 1980s, to the point where SSL became the dominant manufacturer in high end music production. The first two 4000 E consoles went to Battery Studios and RG Jones Recording Studios, with early adopters also including Eden Studios and Sarm Studios in London. Hansa Tonstudio in Berlin ordered three custom 4000 E consoles finished in a distinctive “Hansa blue” colour, two of which remain in service decades later.
SSL continued to refine the 4000 platform and, in 1987, introduced the SL 4000 G Series at the AES Convention in New York. The G Series kept the basic architecture and workflow of the E but introduced a redesigned EQ with different curves and response, along with various improvements in the automation and control systems. Over time, the E and G channel and centre section designs were repackaged into related formats such as the 5000, 6000 and 8000 Series, which were tailored for different applications in music recording, film mixing, video post production and broadcast, using alternative routing and bussing schemes while retaining the core SSL sound. Production of SL 4000 Series consoles continued in various forms until 2002.
By the mid 1980s SSL was already looking beyond purely analogue desks. Digital research and development began in 1985, leading to the 01, an eight channel digital recorder and editor that served as a technological stepping stone for larger systems. This work was expanded into the A Series of digital consoles, launched through the 1990s, which brought SSL’s approach to control, automation and ergonomics into music production, broadcast and post production in fully digital form. In parallel, the company moved its headquarters to Begbroke Manor near Oxford in 1986, building a 4,000 square metre manufacturing facility on the site that opened in 1988. SSL’s UK headquarters remain at Begbroke, reflecting a continuity of location even as its product range has evolved.
The impact of the SL 4000 Series on the recording industry is difficult to overstate. In 1996, Billboard’s Studio Action Chart reported that 83 percent of that year’s number one singles had been produced using an SSL console, a statistic that underlined how thoroughly the brand had penetrated top level commercial studios.
SSL has stated that more platinum albums have been recorded on its consoles than on all competing brands combined. In recognition of its long term influence, the SL 4000 Series was inducted into the TECnology Hall of Fame in 2004 as a product family that had a lasting effect on audio technology and production practice.
Across this period, the 4000 Series was closely associated with a generation of high profile engineers and producers. Bob Clearmountain, Steve Lillywhite, Chris Lord Alge, Tom Lord Alge, Andy Wallace, Mark “Spike” Stent, Alan Moulder, Trevor Horn and others became known for mixes that exploited the 4000’s aggressive dynamics, flexible routing and instantly recognisable bus compressor character, while artists ranging from Phil Collins and Peter Gabriel to countless rock and pop acts in the 1980s and 1990s benefitted from the sound and workflow the consoles provided. Studios such as Townhouse, Hansa, Abbey Road and many major US and European facilities installed 4000 Series desks as their main mix platforms, helping to cement the association between SSL and high end commercial production.
