Objeq Oscillator

Audio Generators

1. Decay Knob Changes the oscillator decay time.
2. Gate Input When connected to a gate signal, dampens the sound when the note stops. Dampening amount is controlled by the knob.
3. Tuning Knob Sets the oscillator frequency when the Pitch input is at 0V. Double-click for middle C.
4. Fine Knob ±1 semitone adjustment around tuning frequency.
5. Hertz Knob ±5 Hz adjustment around tuning frequency.
6. Object Knob Changes the object model, affecting the oscillator timbre.
7. Material Knob Changes the object material from woody to glassy.
8. Tone Knob Adjusts the oscillator brightness.
9. Position Knob Adjusts the position of the exciter on the object.
10. Density Selector Sets the number of modes used to produce the sound, impacting its complexity and realism.
11. Exciter Section Triggers the oscillator. See Exciter documentation for more information.
12. Pitch Input Calibrated for 1V/octave pitch signals.
13. Gain Mod Knob Controls by how much the pitch affects the output volume.
14. Output Oscillator output.

Overview ⚓︎

The Objeq Oscillator is a physical modeling device that can reproduce the timbre of various acoustic objects being triggered either by the built-in Exciter or by any external source. The object’s physical characteristics can be modulated in real-time from any CV signal, allowing a range of sounds, from realistic tones to unique instruments that morph between object types, all with a natural acoustic feel.

This module can be very CPU intensive! Avoid using more than two in a polyphonic patch, and if you use many Multiphonics plug-in instances in your project, don’t load too many patches based on the Objeq Oscillator.

The physical model at the core of the module uses modal synthesis, meaning that each frequency component of the sound is implemented as a resonant filter with its own characteristics. Depending on the module settings, a single note can require over 70 filters. To reduce CPU usage, try choosing a lower Density setting.

Quick Start ⚓︎

• Connect the Keyboard Pitch output to the Pitch input at the bottom-left of the module.
• Connect the Keyboard Gate output to the Trig/Env input in the Exciter section. This triggers the exciter when a note is played.
• Connect the Keyboard Vel output to the Vel input in the Exciter section. This makes the module velocity sensitive.
• Connect the Out jack at the bottom-right of the module to the Output Mixer.
• For the best experience, set the Mode module to Poly.

If everything is connected correctly, you should hear a simple plucked string sound when playing on the keyboard. If you want the sound to stop when the key is released, connect the Keyboard Gate to the Gate input under the Decay knob.

You can use the CV Quick-connect feature to quickly connect the Trig/Env, Pitch, Velocity and Gate inputs by double-clicking on them.

To create a sustained sound instead of a plucked sound, change the Exciter mode to Noise.

Now you can experiment with the module’s settings or read the In Depth section below to learn more about adjusting the sound to your liking.

As shown above, the Objeq Oscillator can function as a simple physical modeling synthesizer with only the Keyboard and Output Mixer as supporting modules.

In Depth ⚓︎

The Objeq Oscillator is a large module that might seem intimidating, but it can be understood easily by breaking it into four simple sections:

Tuning ⚓︎

Tuning is controlled by the main Tuning knob, the Fine and Hertz knobs, their respective modulation inputs, and the Pitch input. See Oscillator Tuning for more information.

Exciter ⚓︎

An acoustic object doesn’t produce sound on its own—it needs to be triggered by an external force. The same principle applies to the physical modeling engine of the Objeq Oscillator. The Exciter section, which is also used in the Tube Oscillator module, fulfills this role. Read its manual page for more details on how to use it.

The Exciter allows the physical model to be triggered by an external audio source instead of its built-in pulse and noise generators. In this mode, the model acts as a filter, similar to the Objeq Filter module.

For filtering an arbitrary audio signal with an acoustic object, we recommend using the Objeq Filter module. It is more CPU-efficient and is designed to react musically when the filtered signal matches the resonant frequency of the object. While the Objeq Oscillator module provides finer control over the characteristics of the acoustic object and a technically more accurate model, it can also produce loud and uncontrolled resonances with some audio inputs.

Physical Model ⚓︎

At its core, the Objeq Oscillator uses modal synthesis to generate sound. Each object type is broken down into modes—which are individual frequencies with distinct amplitude and resonance characteristics. The parameters in the physical model section shape these modes, and all but one can be modulated in real time using any CV source.

Object Type

The acoustic object type can be changed by clicking on one of the icons in the display. The object types, from left to right, are:

• Rectangular membrane
• Drumhead
• Rigid plate
• String
• Marimba
• Beam

The Object knob allows you to set the object type anywhere between two adjacent objects for a greater creative control.

In the physical model, changing the object type adjusts the relative frequencies of the modes to match those produced by the selected object.

A useful trick for creating lush attacks and a less sterile sound is to modulate the Object knob by 1–2% with a slow Pluck Envelope.

Decay

The Decay parameter controls the overall decay time of the sound.

In many musical instruments, the sound stops after a note is played. For example, on a piano, a damper is applied to the string when the key is released. This behavior can be replicated by connecting the Gate input below the Decay knob to the Keyboard Gate output. When the key is released, the decay shortens, causing the sound to fade more quickly.

The Decay Gate knob determines how much the gate affects the decay time. At 0%, the decay remains unaffected by the gate. At 100%, the sound stops almost immediately when the gate falls.

Material

This parameter affects the decay time of each mode relative to the decay time of the fundamental frequency. This property is related to the material of the object. For example, a piece of wood and a piece of steel with the same shape will sound different because their modes vibrate for different durations.

Two key values in the knob’s range are:

• 50%: The decay of each mode is inversely proportional to its frequency—a mode at double the fundamental frequency will have half its decay time.
• 75%: All modes have the same decay time.

Across the range of 0% to 100%, the sound can be said to transition from woody to glassy. Musical instrument-like timbres are typically found around 50%, while more metallic tones appear around 75%.

Tone

The Tone knob adjusts the brightness of the sound by modifying the relative amplitudes of the modes. When centered, the modes have a natural amplitude based on the object geometry. Turning the knob counterclockwise emphasizes lower modes and de-emphasizes higher ones, resulting in a darker tone. Turning it clockwise does the opposite, making the sound brighter.

Position

This adjusts the point at which the object is excited, changing the relative amplitude of the different modes.

The value displayed when turning the knob represents the position relative to the object’s size. At 0%, the object is excited near its edge, and at 50%, it is excited at the center. The knob doesn’t go past 50%, as the effect from 50% up to 100% would mirror the effect from 50% back down to 0%.

Even during the object’s decay phase, the Position knob still affects the sound. Therefore, it can also be thought of as the listening position.

Density

This sets the number of modes used to produce the sound. At lower densities, only the lowest frequency modes are active, making it sound as if a steep low-pass filter had been applied to the object.

For the beam and marimba models, the mode frequencies are so spread out that most of them end up above the hearing range, so the different density settings can sound the same.

For better performance, we recommend finding the lowest density setting that still sounds good in your patch. Using fewer modes can significantly reduce CPU usage.

Output ⚓︎

The main component of the output section is the Out jack, which provides the oscillator’s output signal for routing to other modules in your patch.

The output volume of the physical model is controlled in three ways:

• The gain knob next to the Out jack can attenuate or boost the volume.
• The Gain Mod knob adjusts how much the pitch affects the volume, helping to balance the sound between the lower and higher registers.
• A built-in limiter, indicated by the LED above the Out jack, prevents the output from becoming too loud when resonances in the physical model get too strong. If the LED lights up frequently, reduce the volume with the gain knob.