The atmosphere is a control

In our physically modelled instruments the environment is a control like any other.

Medium, temperature, humidity and the salt content of sea water change the speed of sound and with it pitch and tone. Altitude above sea level changes the density and damping of the air, not the speed of sound. This is calculated from published formulas such as ISO 9613-1.

Time of day, wind and breath add their own influence. One project climate can be shared by several instruments, so they share the same air.

The three listening examples each play the same phrase with only one control moved, loudness matched:

Cold against warm (pipe, -5 °C against 35 °C): in the cold the air column vibrates more slowly, the pipe sounds a good semitone lower, about 120 cents.

Dry against humid (plucked string, 35 °C, microphone 30 m away): over the long path dry air removes more of the high content. At 95 % humidity the same string sounds more open and brighter, at 10 % duller.

Sea level against 3000 m (blown tone): the pitch stays, because altitude does not change the speed of sound. Thinner air changes flow and damping, the tone becomes softer and a little darker.