Thierry's been at it again, and his latest mod sounds great! The mod, demonstrated by Thierry himself in this video, is a small circuit soldered onto the main Etherwave circuit board. In addition to adding nearly 1.5 octaves of range on the low-end, one of the biggest improvements, in his own words, is that "the bass range of this instrument does not longer sound like a dying motorbike". I can't wait to order one myself!
Learn more about the mod at his website: http://theremin.tfrenkel.com