AtkFoa.speedOfSound = 333.0; // (m/s)

NOTE: this value is implied by the current setting of the cutoff
frequency (53 Hz) found in the sc3-plugins code for FoaProximity & FoaNFC

freq = speedOfSound / 2pi // wavenumber = 1
speedOfSound = 53 * 2pi // 333.0

this value is the speed of sound @ 3C
https://www.weather.gov/epz/wxcalc_speedofsound

TODO: consider updating sc3-plugins to align with
AtkHoa.speedOfSound = 343.0