These days, the sequencer is almost synonymous with the digital audio workstation (DAW), but its history goes back way beyond the computer era. From modular synths to '70s drum machines and '80s home computers, sequencers have been used to make life easier for musicians for nearly half a decade.

Essentially, a sequencer is a device that triggers notes to be played back by other equipment, but we'll see that there are a variety of different ways this can be achieved. Whether it's step sequencing, a simple loop-based sequencer or full-blown MIDI DAWs, sequencers are a crucial part of every studio.

The story of the sequencer begins in the days when all synthesizers were analogue and modular: the early 1960s. Step sequencer modules allowed synth users to program repeating loops of notes, With the module producing CV signals to send to oscillators, triggering notes as the loop played. Modular synth step sequencers typically allow the user to set the pitch for eight, 16 or 32 individual steps by adjusting knobs. Each knob controls an individual step's output voltage.

On receiving a clock trigger input, the step sequencer advances to the next step and automatically adjusts the level of the CV output accordingly. After the final step, the sequencer returns to the first step, looping infinitely as the trigger signal repeats.

As synth technology developed, so too did sequencing equipment. The modular synthesizer was largely superseded by the compact analogue synths and drum machines of the 1970s and early 1980s. The sequencer also had to move with the times. Synths such as Sequential Circuits" Pro-One (1981) and Roland's TB-303 (1982) offered integrated sequencers for triggering notes. Typically, the sequencers found in hardware around this time were basic, loop-based affairs, the TB-303's step sequencer being a great example. later, digital technology would allow more advanced sequencers to be built into synths such as the Sequential Circuits Six-Trak (1984). Drum machines offered Similar pattern-based step sequencing functionality. The Roland TR-808 and 909 in particular are famed for their implementation of versatile, expressive step sequencers.

Although the sequencers built into analogue synths were basic, many contained features which set them apart from modular analogue sequencers. Built-in glide control and accent settings allow for variations of expression, while swing settings such as the shuffle control on the TR-909 allow rudimentary control of groove. Crucially, most step sequencers built into analogue synthesizers have a significant advantage over modular equivalents in that they allow the user to store patterns to memory chips.

Song arrangements can therefore also be strung together from multiple patterns, with each pattern recalled from memory when required. However, despite the minor improvements over earlier systems, these sequencers were still not particularly flexible. For greater sequencing power, users turned to dedicated hardware sequencing units which triggered their equipment via wired CV and gate connections.

The development of microprocessor technology meant that recording and playing back complex sequences of CV/gate data became possible in the late 1970s. Roland's MC-8 sequencer offered eight tracks of sequencing capacity but with its fiendishly difficult programming system and priced at nearly $8,000 in 1977 it wasn't a big seller.

The later four track MC-4 (1980) brought the price down and achieved much greater success, becoming particularly popular with synth-based acts such as Kraftwerk, the Human League and Depeche Mode's Vince Clarke. Around the same era, the ground breaking American company Sequential Circu its also developed a number of CV/gate sequencers in the form of units such as the Model 600/800 and Poly-Sequencer for the Prophet-5 synth, but very few were produced.

At the same time, Sequential's Dave Smith was hard at work developing technology that would have a huge impact on sequencing...

The introduction of the MIDI protocol in 1982-3 changed everything. The complex information which could be transmitted over MIDI connections meant that much more powerful sequencing options became possible. When combined with digital programmers, MIDI sequencing offered a new solution to the problem of automating synths and drum machines.

Analogue and digital synth hardware continued to include built-in sequencing options, but the most powerful sequencers were to be found in dedicated hardware units designed specifically for controlling synths. The invention of M I Dl brought with it vastly superior sequencing capability than anything which had gone before. Hardware MIDI sequencers offered similar recording features to their analogue predecessors but user interfaces were generally significantly more friendly. Editing features were still cumbersome at best.

Dedicated MIDI sequencing hardware offered more power than anything the analogue world could have dreamt of at the time, but its days were numbered thanks to the imminent arrival of computer sequencing. With superior editing abilities, higher track counts, better memory features (no more backing up sequences to clunky old cassette machines!) and lower prices, computers were always destined to replace hardware sequencers.

The history of '80s computers is a story for another time, but the standout compute for musicians was undoubtedly the Atari ST, launched in 1985. The MIDI protocol had only been in existence for three years when the Atari was launched, but the ST's built-in MIDI interface made it incredibly attractive to musicians. With synths and drum machines hooked up, the computer could be used as a central control system for all the MIDI equipment. Sequencing software really started to take off once word spread of the Atari 's capabilities.

Other systems such as the Commodore Amiga and early Macintosh models were capable of running similar sequencing software, but the Atari's integrated MIDI ports saved the hassle and expense of adding a MIDI interface. As an aside, this is probably one of the reasons the tracker software we discussed in FM228 thrived on the Amiga platform - even without a MIDI interface or external hardware, trackers could be used as full in the box virtual studios on the Amiga platform.

Computer sequencing programs were initially extremely basic, but the DAWs of today have much to thank them for. Apple's Logic and Steinberg Cubase can both trace their heritage all the way back to the mid-80s. In the case of Apple's Logic, it all started when a company called C-Lab, creators of Super Track on the Commodore 64, released Creator for the Atari ST in 1986. Creator became Notator, then Notator SL and finally Notator logic.

By this point the company had changed its name to Emagic, and Logic was ported to the Mac and Windows platforms. Apple purchased Emagic in 2002 and acquired the rights to logic, dropping Windows support with the release of version six in 2004. Steinberg Cubase can be traced back to 1984, when Karl Steinberg and Manfred Rorup released their program Multitrack Recorder for the C64.

The program evolved into Pro 16 for C64 and Apple lie that same year, then Pro 24 for the Atari ST in 1985 and Am iga in 1986. By 1989 the product had become Cubit (soon changed to Cubase thanks to legal action from a computer company with a similarly named product) and eventually it found its way onto the Windows and Mac platforms where it remains to this day.

In the late 1980s and early 1990s, integrated sequencers saw a brief resurgence as the workstation keyboard enjoyed a wave of popularity. Keyboards such as Korg's M1 and Roland's W-30 combined synthesis with multi-track sequencing features. Up until as recently as the late 1990s, hardware sequencers still enjoyed a small but significant market share. For live performance in particular, the stability of a dedicated hardware sequencer made it a viable option. Manufacturers continued to produce hardware sequencers into the twenty-first century, but sales declined as computers became more and more powerful.

Since the turn of the century, the arguments for hardware sequencers have become weaker and weaker. The computer-based DAW is now at the heart of practically every studio setup, offering MIDl sequencing features in conjunction with multi-track audio recording and editing, digital effects and soft synth hosting. Sequencing generally takes the form of 'piano roll' notation, although musical scores and step sequencing features are also included.