https://en.wikipedia.org/wiki/Ondes_Martenot
https://www.youtube.com/watch?v=yidV0HeVyCg
To my mind, the best of the early (pre-Buchla/Moog) electronic synthesisers was the Hammond Novachord. It's remarkable that a commercial record was released with a polyphonic synthesiser as the sole instrument in 1939, and even more remarkable that it was anything but a novelty - it sounds absolutely gorgeous.
In that video the sackbuts are the three people at the back and there are 2 cornettos at the front.
So this is an early synthesiser that sounded a bit like a sackbut presumably.
[1] A virtuosic curved horn instrument with a trumpet-like mouthpiece but fingering like a recorder.
I wonder if this was done simply to aid the prototyping, or if the intention was that the performer would be changing the timber during the performance, while the instrument is sounding. This seems to be the effect you hear with the klaxon sound changing into a grunty, nasal timbre at the beginning of the Sackbut Blues.
My guess is that it was a prototyping convenience, but it would seem to have big implications for how the instrument is used in performance. A composer writing for it would have to think about mutable timbre not dissimilarly to planning pedal changes for a harp or even thinking about double-stops on string instruments -- there are practical limitations of the performer and instrument that has to be considered.
That actually makes the music a bit more interesting to me than an early 20th-century ideal of "liberating" music from the confines of catgut and sloppy wet wood and metal.
I know, I know, downvote me. But if you people had to be stuck on a desert island with a recording of that thing vs Tommy Dorse or Melba Liston or J.J. Johnson, you know which one you'd choose, and it's not the "electronic sackbut".