Here's a theremin-like VST plug-in for your MIDI editing software.
It's called Spooky Keys (http://www.vstplanet.com/Instruments/VST_Synthesizers9.htm). (At the bottom of the webpage.)
It's basically a nine octave VST synth, but the sound can resemble a theremin. The notes are discrete pitches, but (being nine octaves) the notes are very close together (when played manually) and treated with a fairly heavy delay. There is a "glide" knob that does smooth the transitions somewhat, but no true portamento.
As you can see (http://www.vstplanet.com/Instruments_photos/Full%20view/spook_20keys.jpg), it has four waveforms available and a variety of controls for the ambience, pulse-width for the square waveform, delay, and the vibrato (right side of the X-Y screen).
It can be played manually by dragging the fuzzy ball on the bottom left around the X-Y screen.
To play a serious tune on it, you'll need a software MIDI sequencer.
It's not a real theremin, or even a great emulation, but can provide some amusement for five or ten minutes.
It's called Spooky Keys (http://www.vstplanet.com/Instruments/VST_Synthesizers9.htm). (At the bottom of the webpage.)
It's basically a nine octave VST synth, but the sound can resemble a theremin. The notes are discrete pitches, but (being nine octaves) the notes are very close together (when played manually) and treated with a fairly heavy delay. There is a "glide" knob that does smooth the transitions somewhat, but no true portamento.
As you can see (http://www.vstplanet.com/Instruments_photos/Full%20view/spook_20keys.jpg), it has four waveforms available and a variety of controls for the ambience, pulse-width for the square waveform, delay, and the vibrato (right side of the X-Y screen).
It can be played manually by dragging the fuzzy ball on the bottom left around the X-Y screen.
To play a serious tune on it, you'll need a software MIDI sequencer.
It's not a real theremin, or even a great emulation, but can provide some amusement for five or ten minutes.