Research->Music Instrument->Electric Instrument->Theremin
Provides pictures and information of electric music instruments.

I took this picture at YAMAHA Resort, Nemunosato.
The vertical antenna adjusts tones, the horizontal antenna adjusts volumes. The closer a hand approaches to the vertical antenna, the higher the tone sounds. The closer a hand approaches to the horizontal antenna, the lower the tone sounds. This reaction is opposite to general sense that the closer we approach, we hear the higher volume.
Like analogue synth, Theremin's tuning is distorted effected by temperature and humidity, so it requires tuning at frequent intervals.