How the Other Tones are Created, Vibrato and Chorus

How the VK-8 Works

Vibrato and Chorus

Traditional tone wheel organs provided a total of six different effects: three kinds of vibrato (V1, V2, V3) and three kinds of chorus (C1, C2, C3).

Vibrato is an effect that cyclically modulates the pitch, and chorus is an effect that modulates the pitch to produce spaciousness and depth.

Harmonic bars

The harmonic bars of a tone wheel organ are arranged in ascending order of pitch, from left to right. Borrowing some inspiration from the pipes of a pipe organ, the bars are labeled in “feet,” with 8’ being the fundamental.

There is one exception in the ordering of the harmonic bars, and that is the 5-1/3’ bar located second from the left. According to the pitch order, this should be the third from the left, but since 5-1/3’ is an overtone of 16’, and blends with the 16’ sound, it is placed beside the 16’ bar.

The harmonic bars are color-coded in three colors. The bars whose pitches are in octave relation to 8’ are white, the bars that are not octave harmonics are black, and the lower pitch range is brown.

On tone wheel organs, the highest feet were repeated (“reused”) in the high keyboard range, and the lowest feet were repeated in the low range. This is called “fold-back.”

If an organ had 109 tone wheels, all nine harmonics of the harmonic bars could be sounded by all 61 keys of a tone wheel organ. However, if this were the case, the upper range would be unpleasantly screechy, and the lower range would be excessively low and muddy-sounding.

For this reason, fold-back is used on the VK-8 to produce a well-balanced sound.

Amp Type (Rotary, Overdrive, Tone)

By using a rotary speaker with a tone wheel organ, you can create modulation and a sense of rotation, producing a spacious, three-dimensional sound.

On the VK-8, the volume of the rotary speaker, the time over which rotation will transition between fast and slow, the speed of rotation in fast and slow states, and the sense of spaciousness can each be adjusted independently for the tweeter and woofer.

Reverb

Reverb is an effect that adds reverberation to the sound. Reverb types ROOM, HALL, and CHURCH add the reverberation of differently sized acoustical spaces. The SPRING reverb type simulates a reverb circuit that used springs, and was often found on traditional organs.

The VK-8 lets you adjust the reverb time (p. 57). Also, by turning the [REVERB] knob you can adjust the volume of the reverb (p. 37).