Pitch Detector

1. Pitch Display Shows the pitch of the input signal.
2. Trig Output Triggered when a new pitch is detected.
3. Sensor Output Gate signal. High when a pitch is being detected.
4. Pitch Output Main module output: 1V/octave pitch CV. 0V represents middle C (261.6 Hz).
5. Input Audio signal for which the module will detect the pitch.

Overview ⚓︎

The Pitch Detector module generates a 1V/oct pitch CV from an audio signal.

When a stable pitch can be detected from the audio signal connected to the In jack, the following happens:

• the pitch is displayed at the top of the module,
• the CV corresponding to that pitch is produced by the Pitch output,
• the Sensor output goes high (10V),
• a short trigger signal is generated by the Trig output.

When no pitch is detected:

• the pitch display becomes darker,
• the Sensor output falls to 0V,
• the Pitch output holds the last valid pitch.

Usage ⚓︎

Connect an audio signal to the In input at the bottom of the module (see below for the limitations on the kind of source that can be used). The Pitch output will produce a 1V/octave pitch CV signal.

Connect the Pitch output to any module with a Pitch input (such as the Classic VCO, the Objeq Filter or the Pitch Shifter), or use it as a general purpose modulation source for any module.

You can also process the Pitch output with a Slew Limiter to smooth the signal if the source pitch is not stable. In that case, connecting the Trig output to the Reset input on the Slew Limiter will allow for quick note changes and stable note sustain.

When the Pitch Detector is used as a pitch source for a synthesized sound, the Sensor and Trig outputs can be used to trigger an ADSR to control the sound amplitude the same way that the Keyboard Gate and Trig outputs would be used. See the patch example below.

Limitations ⚓︎

Pitch detection is not an exact science, and this module is limited in what it can do.

For optimal results, take this into account when you use the Pitch Detector:

• Input must be monophonic. Detection will fail or will give unexpected results for polyphonic inputs.

• Input signal should be dry. Reverb, echo and chorus are very detrimental to pitch detection.

• Avoid quick vibrato and deep bends. They may cause spurious triggers on the Trig output and discontinuities in the Pitch output.

• Avoid large transients. Instruments with a strong attack such as guitars, pianos and tuned percussions may have delayed or inexact pitch detection.

• Bass takes longer to detect. There is a noticeable and unavoidable detection lag on low frequency sounds that stems from their longer time periods. In fast bass lines, some notes may be skipped. It gets worse when the bass has a strong or bright attack.

Patch Example ⚓︎

In the following patch, a simple triangle bass is generated one octave below the pitch of the audio input signal. Note that the oscillator pitch is set to C3 (one octave below middle C), and that the Dry/Wet on the Output Mixer is set to the center position so that the input signal is mixed with the generated bass.