Operation Manual

2.2 Tutorial 2 Playing a Synth with a Keyboard 30

signal output corresponds to the highest note played when one or more keys are pressed and to the

last key played when no key is pressed. In order to change the pitch of the VCO, remember that

the mod1 gain knob of the ﬁrst modulation input of the VCO must be turned to the right. In its

center position (green LED on), the gain is equal to 1 and the pitch variations will follow the notes

you play on the keyboard. If you do not want to play an equal tempered scale, tweak the mod1

knob to the left for microtonal variations or to the right for larger variations. You can also use the

pitch bend wheel of your keyboard to change the pitch. Note that the sound is uninterrupted even

after you have released a key on the keyboard. This is because a monophonic keyboard holds the

last note played. To remedy this, we will use the gate signal of the Keyboard module to stop the

note at the right time.

Step 2: Add a VCA

Description

A VCA is a Voltage Controlled Ampliﬁer. More simply said, it is a module that multiplies two

signals. In order to obtain sound only when a key is pressed, we will connect the gate signal from

the Keyboard to the ﬁrst input of the VCA. The gate signal is simply a signal that indicates whether

a note is pressed or not; its value is 1 when a key is pressed and 0 when the key is released. In

this way, if we connect a second signal to the VCA, the output of the VCA will produce no sound

when no key is pressed and will be equal to the second input signal when a key is pressed.

Construction

• Select a VCA module in the Envelopes section of the module library section in the Browser.

• Pull a wire between the ﬁrst Keyboard output, the gate signal, and the ﬁrst input of the VCA.

• Select the wire between the Vlowpass2 output and the Volume input and delete it.

• Now connect the output of the VCO to the second input of the VCA and the output of the

VCA to the ﬁrst input of the Volume.

Figure 15: Tutorial 2, step 2