Tube Oscillator

Audio Generators

1. Tuning Knob Sets the oscillator frequency when the Pitch input is at 0V. Double-click for middle C.
2. Fine Knob ±1 semitone adjustment around tuning frequency.
3. Hertz Knob ±5 Hz adjustment around tuning frequency.
4. Decay Knob Changes the oscillator decay time.
5. Gate Input When connected to a gate signal, dampens the sound when the note stops. Damping amount is controlled by the knob.
6. Open/Close Switch Selects between a tube open on both sides or closed on one side.
7. Tone Knob Controls the brightness of the oscillator.
8. Exciter Section Triggers the oscillator. See Exciter documentation for more information.
9. Pitch Input Calibrated for 1V/octave pitch signals.
10. Gain Mod Knob Controls by how much the pitch affects the output volume.
11. Output Oscillator output.

Overview ⚓︎

The Tube Oscillator takes its name from the physical model of a cylindrical tube that makes up its core. However, it was designed to do more than reproduce the sound of an open or closed tube being hit at one end or otherwise excited. Thanks to its extended decay range, it can be the foundation of great plucked strings, bowed strings, pads, basses, or serve a relatively CPU-friendly complement to a patch built around a more complex sound source.

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 sound similar to a plucked string 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. For a sound more similar to a tube being hit on one end, reduce the decay.

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 Tube Oscillator can function as a simple physical modeling synthesizer with only the Keyboard and Output Mixer as supporting modules.

In Depth ⚓︎

The Tube 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 Tube Oscillator. The Exciter section, which is also used in the Objeq 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 Tube Filter module.

The only differences between the physical models in the Tube Filter and the Tube Oscillator are the support for stereo signals in the former, and the extended Decay knob range in the latter. For pure filtering tasks, you might prefer to use the Tube Filter since it has a smaller footprint in the rack.

Physical Model ⚓︎

As mentioned in the previous section, the Tube Oscillator shares the same physical model of a cylindrical tube as the Tube Filter, but with a slightly extended decay range to enable its use as a more versatile physical modeling oscillator.

Refer to the Tube Filter manual page for more information on the Decay, Open/Close and Tone parameters.

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.