Electronic engineers at Nottingham have found a new way to create sound effects by manipulating the interaction of sound waves, a method that could open up new possibilities in the performing and production of music.
The method was developed in the Faculty of Engineering at the University of Nottingham. The method is a novel concept for sound effect that falls between electronic / digital and mechanical effects. The work has been published in the Journal of the Audio Engineering Society.
The Nottingham team have created a novel solid-state ‘rotary’ speaker inspired on the classic electro-mechanical effect (the Leslie speaker). The device uses a circular array of speakers instead of moving parts. In this approach, the signal is translated across the array electronically rather than mechanically to emulate motion. The modulation of phase in this case, does not occur on an electronic signal to be played on a single speaker, but on the physical sound waves approaching and surrounding the listener. Therefore, making the character of the effect more organic and with greater depth.
The Leslie or Rotary speaker, developed in the 30s for electric organs, uses motors and belts to move horns and baffles to create sound modulation. The Leslie had great impact on popular music which continues to this day through a plethora of emulations and their variations commonly available in electronic, digital and software plug-in formats (phasers, chorus, etc). However, the character of the original acoustic-mechanical effect, provided by the movement of the sound sources, it is considered far superior to its electronic and digital counterparts.
The solid state ‘rotary’ speaker then represents the first attempt to achieve the character of the original Leslie without the impracticality of its mechanical elements. This represents the first significant innovation in sound effects since the advent of digital modelling in the 90’s.
Fernando Perez-Cota, Assistant Professor in the Department of Electrical and Electronic Engineering explains: “Sound modulation for music application is either acoustic-mechanical like the original Leslie or electronic-digital - there is no in-between . This work represents the first attempt to blur this boundary.”
Nicholas Wolstenholme, Masters Engineering student developed the prototype, he adds: “We believe this concept can not only be used to achieve sound modulation like the Leslie speaker but also represents a completely new paradigm in sound effects and sound modulation with new possibilities. It has the potential to offer high quality sound effects at a cost and scale accessible to anyone making music.”
Journal of the Audio Engineering Society
Experimental study
The Solid-State “Rotary” Speaker
16-Sep-2026