Caustic Song file (optional):
The word "Modulation" essentially means to "change"
Caution: when you open this file and turn the Mute off it will produce noise even if you do not press Play or touch a key. This will make sense soon.
The Modsynth is probably the best for learning. With other synths the wiring and inner workings are kinda invisible. Those who understand basic synthesis can deduce most aspects but the Mod is the best to start with.
If you unmute synth 1, noise appears. Aside from Mute you have no control except to turn a volume knob. We need to be able to Modulate the volume. You'll notice nothing is attached to the Mod jack on the Noise Generator module.
Mute synth 1 again and go to synth 2. Notice that a DADSR envelope is now connected to the Mod jack of the Noise Generator. This allows you to "modulate" or "change" the volume of the Noise.
Press a piano key and listen. Now set the Attack time on full and listen. Set the Release time to full and try again.
You have now Modulated the volume using an envelope and discovered you have control over aspects of the volume like how quickly it starts or fades.
Next, you can also Modulate sound using different methods. Commonly, automation and LFOs are used as different and complimentary methods to Modulate or change a sound.
Go to synth 3. Notice there is now a MiniLFO attached. However, the DADSR is already allowing us to Modulate the volume so the jack is in use.
Fortunately we can also modulate the volume in the top right corner of the Modsynth by attaching an envelope or LFO to the jack labeled, guess what... "Volume Mod".
Now pressing a key allows us to Modulate the Noise by turning it on or off. The LFO also Modulates the sound now. The sine wave setting changes the volume smoothly. The square wave setting will change the volume just as it's shape would imply - on or off. The "random" setting on the far right changes the volume randomly and as time goes by it will be your best friend.
Adjusting the Rate of the LFO should be self explanatory.
Finally, for this lesson, go to synth 4 and unmute it. Be sure the other synths ate muted. Press Play and note how the volume follows the automation drawn or recorded.
So, that's 3 different common methods to Modulate the volume:
1 - using as envelope
2 - using an LFO
3 - using automation