Recently, the question was posed to me: Will I have any problems operating my player piano at 8500 ft.? I didn't know the answer, so I started asking people who might know. Before going any further, the most accurate answer to the question is; "hardly any".

Scientifically speaking, Johan Liljencrants gave me the most accurate answer. It goes like this:

"Boyle's law (Robert Boyle, 1627-91) states that Pressure times Volume is constant in a specific gas content at isothermal conditions. So to reduce pressure in a closed volume of 1 cubic foot from sea level 14.7 PSI into 0.4 PSI less demands a volume increasing to 14.7/(14.7-0.4)=1.0279 cu ft, an increase of about 2.8%.

At high altitude, e.g., 10 PSI [absolute], you must expand the volume more, 10/(10-0.4)=1.0417, about 4.2%.

So at the high altitude, a bellows suction pump, driven at the same speed, would produce one or two percent less volume flow of rarified air, and this should be of very little concern."

It's interesting to note that the air pressure at 8500 feet is about 11 PSI [absolute]. So, in terms of how much harder it would be to pedal the pumps, the user would have to pump one or two more times for every 100 pumps. The people who live in Mexico City and Lake Tahoe told me that they didn't notice any difference in the performance of their instruments.

However, there is one concern which should be addressed here. Everyone also agreed that any leakage in the player system would be exacerbated by the typically lower humidity at higher altitudes. I won't get into the scientific explanation here, but basically speaking the thinner air can get into a leak easier than air that is more dense. So, a leaky player will be more difficult to operate at higher altitudes....