There are records that invite you to lose yourself in sound, and then there are records that would quite like you to know exactly what sound is made of before you start losing yourself. "Prime Frequencies", the latest work by Mo H. Zareei under his mHz alias, belongs firmly to the latter category. Its starting point is deceptively modest: the sine wave, that elementary building block of electronic sound, and the prime number, that stubborn mathematical entity divisible only by itself and one. Put the two together and you have the basis for a rather unusual compositional system. Put 47 pieces on a CD and you have something that might initially look like an especially demanding mathematics examination, although the prospect is considerably more entertaining than it sounds.
The connection is more than a clever intellectual exercise. A sine wave represents the simplest form of periodic oscillation, while prime numbers occupy a foundational position in arithmetic. Both are elementary structures from which more complicated systems can be assembled. Zareei takes this parallel as the organising principle for a collection of sonic studies, each corresponding to a particular category of prime numbers. Frequencies and time-domain values are determined by the relevant primes, with algorithmic and aleatoric procedures developed in ChucK, a programming language designed for audio synthesis and real-time sound processing. The result is a work in which mathematical properties are not merely illustrated by sound: they become the parameters through which sound is generated.
The distinction matters. "Prime Frequencies" does not attempt to make mathematics sound beautiful by adding a suitably tasteful electronic soundtrack to it. Instead, it asks what happens when mathematical relationships are allowed to determine the material and behaviour of a composition. The sine wave is stripped of much of the expressive baggage traditionally associated with musical instruments. There are no guitars yearning for a lost summer, no strings performing their customary emotional blackmail, no percussion pretending that every human experience can be resolved through a well-timed crescendo. The basic ingredients are frequencies, durations, numerical relationships and the procedures that connect them.
That reduction does not necessarily mean an absence of complexity. A pure tone may be elementary, but the interaction between multiple frequencies can produce interference, beating and shifting perceptual relationships. Small changes in frequency or duration can have consequences that are disproportionate to their apparent simplicity. The listener is therefore confronted with a peculiar paradox: the materials are minimal, but the system governing them is anything but trivial. What appears to be a straightforward electronic tone can become an investigation into how we perceive difference, repetition and organisation. The ear, meanwhile, is expected to do its part without demanding a melody every thirty seconds. Not everybody will consider this a reasonable arrangement.
The tracklist reinforces the work's unusual character. Its 47 titles read like a gathering of mathematical personalities, some familiar enough to suggest a school textbook, others apparently determined to make the average listener regret having skipped a few lessons. "Fibonacci", "Mersenne", "Fermat" and "Factorial" sit alongside "Wieferich", "Wagstaff", "Woodall", "Motzkin" and "Newman-Shanks-Williams". There are also combinations of categories, including "Safe + Sophie Germain", "Good + Happy + Lucky + Super" and the rather imposing "Centered Square + Centered Triangular + Centered Heptagonal + Centered Decagonal". One might reasonably suspect that the last title was devised by someone who had run out of room on a conference badge.
Yet the nomenclature has a useful effect. It gives each miniature a distinct conceptual identity while making the album feel like a catalogue of related but non-identical experiments. The pieces vary considerably in duration, from fleeting gestures lasting only a few seconds to longer studies such as "Quintuplets", "Quadruplets", "Circular", "Solinas" and "Sextuplets". This difference in scale is not incidental. The short works offer concentrated encounters with a particular numerical category, while the longer ones provide more time for the underlying processes to unfold. The sequence consequently resists the expectation of a conventional album in which every track must contribute to a continuous emotional arc. It is closer to a collection of specimens, although specimens that happen to have been given the opportunity to make themselves heard.
There is a risk in this approach. When a work is built around a clearly articulated conceptual framework, the explanatory text can become more fascinating than the listening experience itself. The danger is that the listener ends up admiring the mechanism rather than engaging with its results, rather like someone spending an entire evening discussing the engineering of a clock without noticing that it has stopped. Zareei's decision to make the compositional code available alongside the album is therefore especially important. It prevents the project from becoming a sealed intellectual object and offers another way into its construction.
The two versions also establish a revealing distinction between composition as a finished recording and composition as an executable process. The CD presents a single rendering of the code, subjected to basic audio processing to provide a more consistent listening experience. The accompanying code version, available in both browser-based and locally compiled formats, dispenses with that additional processing. It allows the pieces to be navigated interactively, displays the numerical values responsible for the active frequencies and, where generative or aleatoric procedures are involved, produces slightly different results each time they are played. In other words, the CD offers a fixed document of the experiment, while the code version exposes the experiment as an ongoing event.
This is not simply a bonus for people who enjoy rummaging around in programming environments. It changes the nature of the work. The code becomes both score and instrument, while the listener is given access to the rules that shape the audible result. The distinction between composition and performance becomes less straightforward: the system establishes its conditions, but its real-time execution can introduce variations that prevent every encounter from being identical. The listener's equipment and hearing also become part of the equation, particularly in the unprocessed version, where the perceived loudness of different frequencies can vary substantially. A computer may be perfectly indifferent to the listener's comfort, but the human auditory system has its own rather uncompromising quality-control department.
The artist's background makes this combination of mathematical thinking and sonic investigation entirely coherent. Mo H. Zareei, an Iranian sound artist and researcher based in New Zealand, has a BSc in physics from Shahid Beheshti University in Tehran, a BFA in Music Technology from the California Institute of the Arts and a PhD in Sonic Arts from Victoria University of Wellington, where he works as a lecturer. Under the mHz name, he has released music through labels including Room40, LINE, Important Records, leerraum and KASUGA, while his wider practice encompasses electronic composition, kinetic sound sculptures and audiovisual installations. His work has repeatedly examined the relationship between noise and formal structures, often using custom-built software and hardware to turn apparently restrictive systems into sources of unexpected activity. His installation "Rasping Music" received the first prize in the Sound Art category at the 2015 Sonic Arts Award, while "Material Sequencer" was shortlisted for the Aesthetica Art Prize in 2024. This is an artist for whom the machinery behind a sound is not an invisible technical detail but an essential part of its identity.
The project also has a significant research context. "Prime Frequencies" was commissioned by Laboratoire formes•ondes as part of "Towards an Aesthetic of the Sine Wave", a research-creation initiative led by Nicolas Bernier at the University of Montreal. The project investigates the aesthetic possibilities of the sine wave through commissioned works, research papers, a database and the development of different approaches to composition and performance. Zareei's contribution is particularly apt because it takes the investigation beyond the familiar question of what a sine wave sounds like. It considers how an elementary acoustic unit might be organised according to a different elementary system, and what aesthetic possibilities emerge from that correspondence.
There is something quietly provocative about this proposition. Electronic music has often celebrated the machine as a means of expanding the possibilities of sound, but "Prime Frequencies" moves in the opposite direction, reducing its resources to an almost austere minimum and then examining the consequences. Its conceptual ambition is not to make the simple appear complicated, but to demonstrate that simplicity is not necessarily the same thing as predictability. A handful of numerical rules can produce an extensive range of relationships, and the most basic ingredients can still resist complete anticipation. The process may be mathematical, but the experience remains dependent on perception, attention and the peculiar ways in which the ear responds to patterns.
The album's 47 pieces could easily have become an academic demonstration with an accompanying audio file, but the decision to present them as individual compositions gives the project a more open character. Their titles are informative without being entirely explanatory, and their different durations suggest that no single formal solution is imposed on every category. The result is a work that can be approached through its underlying theory or simply through the succession of sounds. Neither approach invalidates the other, although the code version clearly rewards listeners willing to look beyond the conventional boundaries of a recording.
"Prime Frequencies" is not an invitation to hum along, unless one's idea of a memorable chorus involves a mathematical constant and a particularly disciplined oscillator. Its pleasures are more cerebral, but not exclusively so. It encourages a heightened awareness of elementary sonic events and the relationships that emerge when they are arranged according to precise conditions. More importantly, it demonstrates that conceptual rigour need not suffocate curiosity. Zareei has devised a system with clear rules, yet the system's output remains open to variation and interpretation. There is a certain elegance in that balance: the numbers provide the discipline, the sound supplies the uncertainty, and the listener is left to negotiate the distance between them.
In the end, "Prime Frequencies" makes a persuasive case for listening to the smallest possible components without assuming that smallness means insignificance. It is a record about foundations, but not one that spends its time gazing nostalgically at the ground floor. Instead, it examines what can be built from apparently indivisible elements, and how much activity can be concealed within a single, unadorned tone. The universe may or may not be humming in prime numbers, but Zareei has at least provided a rather convincing reason to pay closer attention to its basic ingredients.