Ian Fritz Euro Teezer thru-zero VCO

Ian Fritz Euro teezer thru-Zero VCO

This module is a sawtooth-based VCO capable of frequency modulation (FM) extending past zero frequency

into the negative-frequency regime. Thru-zero FM provides a much wider and richer variety of sounds than

"ordinary" (positive frequency only) FM. The negative-frequency version of a waveform is simply a time-reversed replica of the original waveform.

When a VCO is modulated through zero frequency, the waveform slows down to a stop and then speeds back up

in the reverse direction -- just like the wagon wheels in the old Western movies. Here is a picture of the core

sawtooth wave being modulated to negative frequencies. On the left side of the picture the wave is a down

ramp, and on the right side it's an up ramp, with the zero-frequency point being at the broad dip.

The Teezer's output waveforms also include triangle and sine waves, for producing sounds with fewer high

harmonics, as typically used for bell sounds, train whistles, and so on. The unit also features a variable

synchronization control that can be adjusted over a range of settings from hard sync to a fairly loose soft sync.

The module can also serve as a highly accurate and stable "ordinary" VCO (i.e., without the deep FM), with

upramp, downramp, triangle and sine output waveforms.

http://synthcube.com/cart/ian-fritz-euro-teezer-thru-zero-vco