In a documentary about Stradivarius violins they recorded violin with microphones all over the room and then looked the sound waves with colors. The sound of stradivarius violin made big sound bursts much further from the violin compared to normal/extremely good violins. It may be difficult to really be able to study how much there is difference without really good equipments. Meaning even if you could not prove your cas it doesn't matter the proofs are not there.