How Bob Moog brought usability heuristics to the electronic synthesizer
Decades prior to the modern-day computer as we know it, Bob Moog used design principles to bring a once niche instrument to the mainstream, influencing generations of musicians and instrument interfaces.
Image: History Center in Tompkins County
Abstract
It was the 60’s and electronic computers were still a cryptic technology that remained obscure to most, a far cry from today where around 6 billion active smartphones are owned by users around the world, effectively giving the majority of the world’s population more compute power than the most advanced super-computers of the ’60s.¹ Although the technology then would be considered primitive by today’s standards, sentiments about the computer’s potential were eager and optimistic, especially among electric engineers such as Robert A. Moog, who saw the future potential for machines to make music, a concept that then seemed outlandish.
In this article, I will be taking a design methodology approach to study some of the heuristic principles behind Bob Moog’s Minimoog Model D synthesizer design, how it re-imagined the sound synthesis experience, and the impact it had in setting a new standard for the interface design of synthesizers. These heuristics will help us better understand the lineage of decades of instruments that would follow early commercial synthesizers such as the Minimoog.
Section 2: Aesthetic and minimalist design
“Interfaces should not contain information which is irrelevant or rarely needed. Every extra unit of information in an interface competes with the relevant units of information and diminishes their relative visibility.”²
When Bob Moog’s Minimoog Model D was introduced in 1970, it set a new precedent for interface design in synthesizers as we know them today, a piano-style keyboard connected to a circuit board with knobs and sliders. Prior to this, the synthesizer looked quite different.
Starting in the 1950s and continuing during the 1960s, the earliest synthesizers were introduced in the form of the modular synthesizer, a complicated machine consisting of dozens of sections, or “modules,” connected manually by cables to program sounds. These machines resembled more a complicated computer in an evil scientist’s lab rather than an instrument in a musician’s studio. Additionally, they were difficult to access due to their cost, limited production, and required knowledge to operate them. These developments created an opportunity to redesign and re-envision the sound synthesis experience that would be soon addressed by the Minimoog.
Image: Ryunosuke Kikuno via Unsplash.
Upon its release, Moog’s Minimoog condensed a significantly complicated instrument down to a considerably smaller format that could be more easily adopted by musicians. Unlike its predecessors, which seemed to tailor their designs for electrical engineers and specialized scientists knowledgeable of electronic sound synthesis, Moog’s design started with the user first. Even Moog himself touches on this in the context of his process saying, “Artist feedback drove all my development work… The point is that I don’t design stuff for myself. I’m a toolmaker. I design things that other people want to use.”³
“Artist feedback drove all my development work… The point is that I don’t design stuff for myself. I’m a toolmaker. I design things that other people want to use.”³
— Bob Moog
Rather than asking users to utilize a complex web of cables to connect signal paths as they would in a modular synthesizer, the Minimoog presented a more simplified experience. “This instrument was a hardwired subset of the large modular systems available before;” wrote Joseph Paradiso comparing the Minimoog to its modular predecessors.⁴ Paradiso continues to observe that, unlike modular synthesizers, “signal routing between components was controlled entirely by a set of switches and potentiometers.”⁴ This contrast between the modular design’s endless possibility for exploration and the Minimoog’s more simplified design is a helpful illustration of analysis paralysis and the Paradox of Choice. UserTesting.com defines the Paradox of Choice as, “an observation that having many options to choose from can cause people to stress and problematize decision-making.”⁵ In the Minimoog’s case, its minimalist design was not simply a matter of aesthetic but also of improved user experience.
In this process of stripping sound synthesis down to switches and potentiometers is where another one of the Minimoog’s strengths lies. No longer did users have to find their way through a tangle of wires with unclear status indications. The Minimoog’s simplified knobs and signage provided users a clearer roadmap of where they were in their sound synthesis journey.
Visibility of System Status
“The design should always keep users informed about what is going on, through appropriate feedback within a reasonable amount of time.”²
The Minimoog employs a few different methods of indicating status to the user. Most obvious is the knob function, which is matched to labels indicating increments of sound modeling, allowing the interface to visualize system status for the user. In Synthesizer user interface — lessons learned from a heuristic review, authors Allan Seago, Simon Holland, and Paul Mulholland refer to a similar concept writing, “the user of a typical synthesizer is able to determine the current ‘state’ of the sound being edited by the parameter values displayed.”⁶ The writers go on to add that, in addition to visible parameter values, the process of experimentation through trial-and-error also allows the user an auditory path to the visibility of system status, “[the typical user] can also audition the effect of the editing process by pressing a key.”⁶
Knobs and switches are assigned other types of visual cues to describe their function. For instance, in the case of the Minimoog, blue switches are matched to audio signal flow while red switches are matched to control voltage signal flow. Knobs and switches are also categorized in relevant groupings through labeling areas for clarity. This labeling not only provides clear functions for each knob but also allows users to visualize the signal flow in their sound synthesis.
When we look at the lineage of music produced with the Minimoog, from Parliament to Pink Floyd and Sun Ra, it’s hard not to draw a relationship between its usability and its ubiquity. While many of the Minimoog’s sounds could be recreated or approximated in earlier synthesizers, it was the Minimoog’s interface design itself that facilitated discovery for the user, making it easier for musicians to create sounds not heard in popular music before. And this is one of the Minimoog’s key qualities.
Image: MusicRadar
Although the Minimoog’s knob interface would, to the everyday person, seem tantamount to that of any other synthesizer, the Minimoog’s design approach was the first of its kind. Never before had a synthesizer been designed with pre-wired modules controlled exclusively by knobs and keys rather than wired signal paths. However, what was once a revolutionary design has, after decades of computational advances, arguably become a dated and superfluous design. It is true that newer digital synthesizers and electronic music devices have evolved past the need of numerous knobs. They have done this, primarily, by nesting access to secondary functions within sub-menus.
“The user interface should show how it wants to be used; important affordances should be obvious and feedback should be positive and reassuring.”³
— Eric Church, Director of Design at Moog
Curiously, however, older analog synthesizers have seen a massive recent resurgence in market demand. It could be argued this is in part due to their distinct and iconic sound. More importantly, electronic analog instruments provide a more direct, visible, and interactive interface than those of digital instruments. Moog Music, which declared bankruptcy in 1987 as digital synthesizers disrupted the market, resumed operations in 2002 and has since launched a large number of successful new analog products, including a reissued Minimoog. Korg, known in the 1980s, 1990s, 2000s, and early 2010s for their digital instruments, has recently pivoted into analog instruments. In an intensely digital world, users are actively seeking the convenience of simplified interfaces. Rather than choosing instruments that can do everything, users are opting for more limited analog instruments that can do less, yet provide an experience with more feedback and visibility. Having a dedicated knob for each function in the Minimoog and other analog instruments saves the user the need for “menu-diving,” or the practice of having to search for secondary functions hidden underneath sub-menus.
Eric Church, Director of Design at Moog writes of synthesizers, “The user interface should show how it wants to be used; important affordances should be obvious and feedback should be positive and reassuring.”³ Church’s words bring light to why analog interfaces are so successful with users. They not only provide immediate visibility but also generate perceivable feedback to the user, creating an experience that embraces discovery and experimentation.
Image: AMAZONA.de
User Control and Freedom
“Users often perform actions by mistake. They need a clearly marked ‘emergency exit’ to leave the unwanted action without having to go through an extended process.”²
An added advantage that appropriate feedback brings to the Minimoog’s user experience is inviting experimentation. In a study titled, Musicking with an interactive musical system: The effects of task motivation and user interface mode on non-musicians’ creative engagement, Yongmeng Wu researched user’s interactions with a custom-made musical interface containing knobs and buttons that played samples of sounds. Wu found that, “participants report playing experimentally is intuitive, engaging and responsive for beginners to learn and explore, because of the direct sound feedback from interactions.”⁷ While Wu’s interface was vastly different in shape from the Minimoog, its primary vehicle is still that of knobs and buttons and, one may even argue, is a branch from a long lineage started by early electronic instrument interfaces such as the Minimoog. Wu’s research shows that, while to an outside observer, synthesizers appear to be complicated and cryptic machines, they invite play by the user, regardless of whether it is a novice or an experienced professional controlling the knobs.
“Almost every other portable synth to come after the Minimoog employed a similar control. If [Bob] had patented [the pitch wheel], he would have been an extremely wealthy man.”⁹
— David Borden, Moog’s associate
In contrast to electronic instruments, it is generally understood that a traditional musical instrument does not meet the user at the novice level. Rather, it is the user who, through iterative practice, develops enough experience to master the product. Unlike traditional instruments, analog synthesizers such as the Minimoog are forgiving of error. Through a broad palette of sounds as well as an interface that lends itself to play, the Minimoog ushered in an era of experimental music. Trained composers (eg. Wendy Carlos, Mort Garson) and self-taught musicians (eg. Frank Zappa, J Dilla) alike, throughout the decades, have gravitated to analog synthesizers such as the Minimoog as a vehicle for new sonic possibilities with more interest in discovering new sounds rather than for mastering the instrument’s usability as one would see with traditional instruments.
Another way in which the Minimoog enabled discovery and freedom for the user through its interface was with the invention of the pitch wheel, which introduced a new variety of sound qualities for users. Prior to the Minimoog, synthesizers were tuned to play specific notes on a keyboard, making it hard for users to add an element of expressiveness to their sound. The Minimoog’s pitch wheel introduced the ability for users to change the pitch of a note in real-time, providing yet another source of play and experimentation. Today, the pitch wheel is such a ubiquitous part of synthesizers’ and keyboards’ interfaces, that David Borden, Moog’s associate, once observed, “Almost every other portable synth to come after the Minimoog employed a similar control. If [Bob] had patented [the pitch wheel], he would have been an extremely wealthy man.”⁸
Conclusion
While early synthesizers such as the Minimoog mostly utilized a re-envisioned piano interface in the form of a keyboard to activate sound, it was the development in the sound synthesis interface that gave rise to an interest in the possibilities for new modes of user interaction, whether some that focused on play or others that focused on experimentation.
Through unique design choices such as the implementation of pre-wired modules that eliminated the need for manually patching sound signal paths (which add friction for the user), clear visibility of system status as evidenced by knobs and switches, and the invention of the pitch wheel, Bob Moog introduced a design interface in the Minimoog that would become a roadmap for electronic instrument designers to follow. As a result, Moog would not only define generations of musical instruments through an enormously successful instrument design but, in doing so, also leave a lasting impact on a plethora of musical styles: an object-lesson for the way in which experience design spills over into many facets of our culture.
References
- Statista | Number of smartphone subscriptions worldwide from 2016 to 2026 by S. O’Dea
- Nielsen Norman Group | 10 Usability Heuristics for User Interface Design by Jakob Nielsen
- Bjooks | Push Turn Move: Interface Design in Electronic Music by Kim Bjørn
- MIT Media Laboratory | Electronic Music Interfaces by Joseph Paradiso
- UserTesting | How to use the paradox of choice in UX design to increase conversions by UserTesting
- The Open University | Synthesizer user interface — lessons learned from a heuristic review by Allan Seago, Simon Holland & Paul Mulholland
- Human Computer Studies | Musicking with an interactive musical system: The effects of task motivation and user interface mode on non-musicians’ creative engagement by Yongmeng Wu
- Red Bull Music Academy | Minimoog: The First Truly Portable Synthesizer by Sophie Weiner
