How to create drum sounds in ZynAddSubFX or Yoshimi, Part 1
This tutorial will assume basic familiarity with Yoshimi or ZynAddSubfx. We will cover how to create -- to synthesize -- some basic electronic sounding drum sounds. When creating patches, it is very important to have some decent headphones or studio monitors. You'll want to be able to hear the low frequency sounds that we may be creating. When creating patches, it is helpful to have the Virtual Keyboard window open so you can test your patch, or you may wish to use a real MIDI keyboard to trigger your sounds.
As stated before, a working knowledge of Yoshimi or ZynAddSubFX is helpful. This tutorial mentions what knobs you should turn, but does not mention what these knobs do.
Most synth drums are modeled on the idea that when a stick or mallet hits a drum, the drum head is compressed, which tunes the drum up. When the stick or mallet leaves the drum and the vibrations leave, there is a lower pitch, because the drum head has relaxed.
If you start with a blank patch, you will notice that the patch is just set up for a basic sine wave. We can start to shape this sine wave to sound like a kick drum, using this idea that the pitch of a drum when hit goes from high to low.
Click Edit/Edit instrument on the main window, and then click the Edit button under ADDsynth. Since we will only have one possible tuning for our kick drum, open the Voice Parameters window and click the 440Hz checkbox. This will ensure that every key pressed is tuned to A (440 Hz.)
Back on the ADsynth Global Parameters window, lets turn the R.dt knob on the Amplitude Envelope to 62.5 to let the sound decay when a key is released. Next, change Octave from 0 to -3. This is what a kick drum's pitch might rest at. You'll need better than laptop speakers to hear this tone. At this point, if you were creative, you could use this kick drum sound in a song. However, we're looking for a more complete sound.
Next lets use the Frequency Envelope. Turn A.val up to 117. Listen to how this has changed the sound. Next, change A.dt to a value around 35.4. Listen to how this has changed the sound.
A more advanced kick drum
With a real kick drum, we also might imagine that there is more harmonic content during the start of a kick drum hit then there is when the sound has resolved to a softer vibration.
To approximate this, we will change the oscillator on our kick drum from sine wave to a square wave. To do this, click Show Voice Parameters, then the Change button under Voice Oscillator. Under the Base Func. box to the right, choose Pulse from the Base F. drop down menu. Our kick drum should now sound like a nasty buzz.
So back at the ADsynth Global Parameters window, under Filter Parameters, set C.freq to 18.43. Set Q to 38.10. Under filter envelope, set A.val to 104.39. Set A.dt to 26.79. We've now made it so the front of the kick sounds punchy, yet it resolves into a softer tone.
A kick drum sounds okay on its own, but it happens to go nicely next to a snare drum. Stay tuned for Part II of this tutorial, where I will cover how to use the Drum Kit mode, and create a snare drum sound.