We measured the acoustic Frequencies emitted by an argon plasma torch. At c
onstant intensity, acting on the anode - cathode distance, indirectly monit
ored the are voltage. The results on the evolution of the observed acoustic
frequencies suggest that their position is mainly a function of the are te
mperature. The poorness of the are temperature estimation from enthalpy bal
ance does not allow to ascertain that it is the case. Direct measurements o
n the are column must be performed to demonstrate this hypothesis.