I was told those Starships were loud as hell on the inside. The prop noise on either side of the tailcone would reverberate, essentially turning it into a huge speaker, blasting the prop noise throughout the cabin. I've got a family member that was a scientist for Beech Raytheon. The Starship issue became one of his projects. "How to quiet it down". The only thing they could come up with was to add a complete interior active noise reduction system. Tons of little speakers and mics throughout the walls of the cabin, sampling the noise, inverting the sound signature and pumping it back into the cabin. It weighed a bunch, cost about a million dollars, and quieted the Starship down to approximately that of a Kingair. That was it. That killed it. Plus they wanted to sell business jets and the Kingair was alive and well. No need to fuck around with such a problematic plane as the Starship.