The original Martinetta was played with a small wind tube. Here the wind goes trough the tube to a small pipe, so that the player had the typical blowing noise with the characteristic edge tone. Behinde the pipe was a small microphone, which transfered the pressure fluctuation into voltage fluctuations. After a low pass filtering these fluctuations have been the control voltage for the width, shape and hight of the pulses generated in the sound processing unit, as well as for the transients (beginning and ending of the sound) and the small modulations in the timbre
The Variophon worked like the Martinetta. but it had a recorder-like mouthpiece, so there was no tube with a small pipe and no edge tone. The player could add a artificial blowing noise with the help of a noise potentiometer. He could also adjust the instrument to his personal breath intensity, while a LED chain shows the dynamics from pp to ff.
The Variophon gig had also the possibility to influence the modulations (caused by the musicians breath) in two ways: With the help of the "Frequency Modulation" potentiometer the player could adjust the strength of the vibrato and with the help of the "Spectrum Modulation" potentiometer the player could adjust the strength of the fluctuations of the partials.
In the blow controller the blowing of the player was transferred with all minimal fluctuations in a fluctuating controlling voltage, which influences the pulse forming sound generating process and the circuitry of timbre dynamics.