Z-Wah: Appropriating the Wah via Digital Impedance Synthesis

Francisco Bernardo, and Andrew McPherson

Proceedings of the International Conference on New Interfaces for Musical Expression

Abstract

Digital impedance synthesis is a viable technique for appropriating and augmenting electronic musical instruments and effects. It enables in-circuit augmentation by replacing selected analog components with a low-latency embedded system that presents a programmable voltage-current relationship to the surrounding circuit. By defining the hybrid boundary between the analog and digital as an impedance relationship rather than a unidirectional control stream, the technique supports reciprocal coupling of subsystems, mutual influence, dynamic emergent interaction and complex behaviour. We demonstrate the approach with an augmented wah pedal that embeds a hybrid virtual-analog system which replaces key passive elements inside the resonant network, potentially allowing a continuum from close emulation to deliberate mismatch and instability as musical material. The contribution is a method for augmenting legacy electronic instruments from within their circuitry and expanding the space of repeatable and exploratory modifications, along with design implications for directionality, feedback, and the aesthetics of hybrid idiosyncrasy.

Citation

Francisco Bernardo, and Andrew McPherson. 2026. Z-Wah: Appropriating the Wah via Digital Impedance Synthesis. Proceedings of the International Conference on New Interfaces for Musical Expression. DOI: 10.5281/zenodo.20784177 [PDF]

BibTeX Entry

@inproceedings{nime2026_55,
 abstract = {Digital impedance synthesis is a viable technique for appropriating and augmenting electronic musical instruments and effects. It enables in-circuit augmentation by replacing selected analog components with a low-latency embedded system that presents a programmable voltage-current relationship to the surrounding circuit. By defining the hybrid boundary between the analog and digital as an impedance relationship rather than a unidirectional control stream, the technique supports reciprocal coupling of subsystems, mutual influence, dynamic emergent interaction and complex behaviour. We demonstrate the approach with an augmented wah pedal that embeds a hybrid virtual-analog system which replaces key passive elements inside the resonant network, potentially allowing a continuum from close emulation to deliberate mismatch and instability as musical material. The contribution is a method for augmenting legacy electronic instruments from within their circuitry and expanding the space of repeatable and exploratory modifications, along with design implications for directionality, feedback, and the aesthetics of hybrid idiosyncrasy.},
 address = {London, United Kingdom},
 articleno = {55},
 author = {Francisco Bernardo and Andrew McPherson},
 booktitle = {Proceedings of the International Conference on New Interfaces for Musical Expression},
 doi = {10.5281/zenodo.20784177},
 editor = {Benedict Gaster and João Tragtenberg and Anna Xambó and Tom Mitchell},
 issn = {2220-4806},
 month = {June},
 note = {},
 numpages = {6},
 pages = {468--473},
 title = {Z-Wah: Appropriating the Wah via Digital Impedance Synthesis},
 track = {Paper},
 url = {http://nime.org/proceedings/2026/nime2026_55.pdf},
 urlsuppl1 = {http://nime.org/proceedings/2026/nime2026_55_file01.wav},
 year = {2026}
}