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Topic: String Symphonizer

Jon Johnson

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The Freeman String Symphonizer is a 5-octave synthesizer of the 1970s. The Freeman has 25 oscillators. The tuning relationship is not perfect, but it can never vary. The other 24 oscillators are assigned two to each of the 12 notes. Thus there are 3 separate pitch references for each note. Each pitch is slightly different, thus creating an analog warmth as the tones of 2 out of 3 gradually drift a tiny amount to give a dynamic beat frequency between them, much like real instruments gradually change in pitch ever so slightly due to temperature changes.

The Freeman has three complete sets of tones that can be mixed to create more or fewer overtones in the sound, as one rank is tuned an octave below the other from the beginning. The 'High' and 'Low' buttons on the front panel select which group is selected, or both can be mixed for a thicker octave overtone on each note. The 'Low' must be on to hear anything on the highest octave because there are not enough frequency divisions to layer the two across the whole 61-key keyboard.

Because all tones are present all the time, it had no restrictions on how many notes could be played at once, unlike most synthesizers at the time, which were often monophonic.

The Ensemble effect invokes thickness But two tones have one discrete oscillator per note have an 'animation amount' slider associated with them. 6 low-frequency oscillators are grouped to notes such that it maximizes the effect for typical chords. In other words, it makes it always sound like there are as many different vibrato rates as possible to again simulate an actual symphony. A built in spring reverb helps simulate a hall environment. And again one could choose 'cello' (16'), and 'violin' (8') tones.

There was a 'touch' (delayed) vibrato setting, and a 'glide' switch on the foot volume pedal (found also on many Lowery home organs), which dropped the pitch one-half step. This made it unique compared to other string machines that had only one oscillator and relied on delay line chips to produce the ensemble effect (chips that have to reduce the audio bandwidth to mask the digital clocking).

It was a heavy machine - about 70 lbs - and was rather durable except for the removable keyboard cover which looked like it hinged up, but rather pulled straight out.

View full synthesizer

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