The Beilfuss Step Synthesizer

flickr set by John Grabowski

"Pics of the Beilfuss Step Synthesizer, as shown by Beilfuss Synthesizer Co. President Keith Williams at the SEAMUS 2009 National Conference held at Sweetwater Sound in Fort Wayne, Indiana."

http://www.beilfusssynth.com/
Note Beilfuss was mentioned in the Electronic Keyboard Reference Guide from 1984 - 1985.

via sequencer.de, via John:
"Even though the synthesizer has a whopping 93 keys, it is essentially two connected 4-octave synthesizers. I was given complete documentation, I’ll see what I can do to post more.

From what I was told, this synthesizer is a completed prototype, and has not yet been put into production."

via http://www.beilfusssynth.com:
"Unlike any analog or digital synthesizer's controls, the patented tone control consists of sixteen steps simply outlining the waveform as set by the Signal Controls you see at the left of the control panel. Similarly, the envelope and filter contour transients and their time intervals are also set by the Signal Controls for rhythms or extended notes. You may easily add prompted, parallel voicings, combining settings of both sides for complex notes.There are 32 controls and 142 pushbuttons for direct programming. Dedicated LED pushbuttons always read out their side of the full eight octave, split keyboard. Five octaves of transposition are possible."

Update via WD on the AH list: "Here's the patent, for anyone interested in reading about the "patented tone control": link (US Patent Number 4495846)"

Update: I sent email to the contact alias on site and received the reply further below, after the images.




"Step Synthesizer Functions

The Step Synthesizer is built around the unique Signal Controls on the left side of the instrument.
The sixteen slide controls, side by side, represent either the literal waveform, the envelope or filter contour curves (like ADSR’s), or the time intervals of the steps in the envelope and filter contour.
The circuitry is all digital, however the organization is based on analog synthesis.

The waveform values appear in the sixteen character LED readouts and may be adjusted while playing. For the envelope and filter contour, they may complete after the key is released or repeat as long as the key is held. Keyed rhythms may be input very simply. The time intervals, ranging 2ms to 2 sec, may be factored slower or faster. A stopwatch timer automatically divides for the equal intervals and enters the resulting values. Then, when altering individual time intervals, a constant sum may be maintained.

The Signal Controls may be moved any two together to set all values equal.

There are two identical instruments both sharing twenty voices and sixty-four programs. There is an alternate group (bank) of sixty-four. The eight octave keyboard is split between middle C and B.
The split point may be varied or floated. Four octaves of transposition are possible with key transposition or transpose rate control with programmed transposition setting. A full range pushbutton will automatically set the two transpositions to piano keyboard. The ergonomically positioned levers add up to an extra octave of transposition. There is key velocity, pitch, and aftertouch patching.

The 440 square inch control panel has dedicated LED pushbuttons and controls for both sides. The edit sections allow full 1 in 256 resolution adjustment of individual control settings of saved programs for both sides.

There may be up to ten voices in parallel with easily prompted editing of voice volumes and tunings. Voices may have the settings of the opposite side’s program selection. Voice reassignment modes consist of Chordal, Single Keyed, Unison, and overflow modes. There is a Legato Notes function.

Glide start and glide functions may be smooth or stepped, key release-ordered or two key overlap. Separate rise and fall controls may be set.

Programs are reset by a dedicated pushbutton. Programs are saved, inserted, deleted, or rotated in the group of sixty-four programs. Partial recalls of separate Signal Controls divisions, individual controls, and voicings are possible.

Almost all control values may be set by foot controls and some pushbuttons may by actuated by foot switches. There are program advance foot switches. The headphone jack has volume and separation controls.

MIDI has selective transmit and receive enables for Notes, Programs, Common, and Exclusive messages. System Exclusive saves the sixty-four program groups to computer or audio recorder.
Self diagnosis of circuit boards is included."