Ferran Lega Lladós, an artist and lecturer at the Universidad de Lleida who works with acoustic patterns himself, published this in Barcelona, Investigación, Arte, Creación in October 2022. The claim is direct: Margaret Watts Hughes was the first woman to treat sound as a plastic tool within visual art, working before the figures usually named as precursors of the discipline.
The method is documentary rather than experimental — tracing evidence that she was deliberately constructing visual works from sound vibrations at the end of the nineteenth century, and asking why the canon of sound art has almost no room for her.
It is a short open-access paper and the framing is advocacy, which the author does not hide. Read alongside the Public Domain Review essay it makes a reasonable case, and the bibliography is a useful route into Spanish-language writing on cymatics that rarely surfaces in English.