Pulse

1. Length Knob Set the length of the pulse.
2. ×100 Switch Multiplies the length of the pulse by a factor of 100.
3. Cutoff Knob Cutoff frequency of the built-in low-pass, band-pass and high-pass filters.
4. Amplitude Knob Controls the amplitude of the pulse.
5. Vel Knob Exponential modulation of the amplitude.
6. Trig Input Triggers the pulse. The pulse can also be triggered manually with the push button.
7. Boost Knob Boosts the amplitude of the filtered outputs.
8. Filtered Pulse Outputs From top to bottom: high-pass (12 dB/oct), band-pass (6 dB/oct) and low-pass (12 dB/oct) outputs.
9. Pulse Output Raw pulse output, bypassing the filters and the Boost gain.

Overview ⚓︎

The Pulse module converts a trigger signal into a rectangular pulse with the specified length and amplitude.

In addition to the raw pulse output, three filtered outputs are provided: high-pass (HP), band-pass (BP) and low-pass (LP).

Here’s an example of the possible outputs for a short and long pulse length, with the default amplitude settings:

See the Use Cases section for ideas on how to use it.

In Depth ⚓︎

Pulse Length ⚓︎

When the ×100 option is disabled, pulse length will be from 0.1 millisecond when fully counterclockwise to 100 milliseconds when fully clockwise. When it is enabled, the pulse length will be from 10 milliseconds to 10 seconds. Using the modulation input, it is possible to produce even longer pulses.

Once a pulse is triggered, its length will not change even if the knob is moved or a modulation signal is applied.

Pulse Amplitude ⚓︎

The default pulse amplitude is 10V, which is in line with the Keyboard gate or ADSR output level. In some use cases, you might want to set a different value with the Amplitude knob.

Double-clicking on the knob will set the amplitude to exactly 5V.

When using the Pulse module as a trigger source in a physical modeling patch, you may want to modulate its amplitude exponentially by connecting the Keyboard Vel output into the Pulse Vel input. When doing that, it may be advisable to lower the amplitude, because the raw pulse output is clipped at 40V.

Filtering ⚓︎

The module contains a built-in state variable filter with 3 outputs: low-pass, band-pass and high-pass. The low-pass and high-pass filters have a 12 dB/oct slope, while the band-pass has a slope of 6 dB/oct.

The Cutoff knob sets the filter’s cutoff frequency.

Filtering will lower the amplitude of the output signal, so the gain of the filtered outputs can be increased with the Boost signal. The filtered outputs begin saturating at 20V, which is signaled by the Over LED. In any case, the output never goes beyond 40V.

Use Cases ⚓︎

Trigger-to-Gate Converter ⚓︎

This module can convert a trigger or a gate signal into a new gate signal with a specific length:

1. Connect the trigger signal into the Trig input.
2. Set the Amplitude knob fully clockwise to 10V.
3. Set the desired gate length with the Length knob. Enable ×100 option for a longer gate.
4. Use the raw pulse output as a gate signal to control another module such as a VCA or an ADSR envelope.

Impulse for Filter ⚓︎

A pure tone similar to a tuning fork can be obtained by connecting the raw pulse output to the input of any resonant filter (such as the State Variable Filter) with a high Q factor. This works best when the pulse length is very short (<5ms).

This can be used as a building block for analog percussion patches.

Physical Modeling ⚓︎

The Pulse module can be used with the Objeq Filter to simulate a mallet hitting a physical object. This works best when the pulse length is very short (<5ms) and the Objeq Filter resonance is high.

The richest signal will be achieved by using the raw pulse output.

The low-pass output will steeply attenuate frequencies above the Cutoff value, which may be desirable for bass or kick sounds.

The high-pass output will steeply attenuate frequencies below the Cutoff value, which may be desirable for brighter metallic sounds.

The band-pass output will slowly attenuate frequencies below and above the Cutoff value. With a cutoff frequency lower than the Objeq Filter’s Cutoff, it will behave like a brighter low-pass filter.

Changing the pulse length produces a comb filtering effect that can somewhat simulate changing the playing position on a physical object. A very short pulse will be similar to playing very close to the edge of the object, and a longer pulse will be similar to playing closer to the middle. However, for lengths greater than 5ms, the raising and falling edges of the pulse might be heard as a double attack.