Having a background in telecoms and a keen interest in shortwave radio, the concept of an AM-transmitting cello intrigues me. Assuming the idea had never been considered before, it certainly sounds inventive enough to be patentable. I am not aware if a patent application was ever filed for it though and I suspect that patents will not be high on the artist's priorities.

That is not surprising, of course. Artists are typically more focused on the art and its message than stopping third parties from using the technology. Nonetheless, art-based inventions are patented: I have handled a number. Michael Jackson's 'anti-gravity' shoes are a good example of such a patent (I should stress that I was not involved though). 

Importantly, patents should be seen as a business tool, not just a certificate of inventiveness. Inventors regularly ask us if their innovation will make their fortune, but patent attorneys may not be best qualified to answer such questions. We can advise on whether a patent might be granted, but the value of that patent to a business depends on many factors.

There may be a lesson here for fast-moving, highly innovative industries, such as IoT. Patents can be seen as an important step in developing a new business, but these patents will have the most value when they are obtained as part of a more complete business strategy.