Bells and Whistles
On this page, we’ll explore
some odds and ends that can make the pipe more interesting.
Shaping the breath noise
Our model’s breath noise is
pretty drab: we can control the level,
and have a basic tone control in the Noise module’s Color control. But that’s it. Some additional EQ would be welcome.
One quick and easy solution
is the Vocal Filter. It’s a one-module
solution that can shape the noise into various vowel sounds. It has a frequency control, a resonance
control, and can morph between up to three different vowels. Quite a lot for a single module. Below is a patch that uses it.
Growling
Growling is when a wind
instrument player interrupts the air pressure into the instrument at a fast
rate, typically 15 to 30 Hz.
Growling is similar to
vibrato, and we’ve already implemented vibrato on a previous page. Below is a patch that growls. The LFO controls the rate, and the “Growl
Amount” knob controls the amount.
Controlling amplitude with velocity
Controlling amplitude with
key velocity seems like a simple thing.
But there’s occasionally a complication on the G2: when playing from note to note on a
monophonic patch, velocity differences can sometimes be so sudden that they can
make an audible click in the sound.
To compensate, we’ll add a
small amount of glide into the system.
Because it’s common to use the Velocity morph to control a panel knob
that controls patch volume, we’ll make our patch compatible with this.
In the patch is below, the
“Output Level” knob controls the patch’s volume, and is connected to the
keyboard velocity morph group. But the
audio signal doesn’t go through this knob.
Instead, the knob simply controls a DC voltage which is used to control
a VCA. A Glide module between the knob
and the VCA protects us from clicks if there are large changes in velocity from
note to note.
Chiffing overtones during the attack
A neat sound is when a wind
player briefly overblows on a note’s attack, causing a short higher-mode
vibration. Our model doesn’t have this
ability built into it, but it’s not difficult to add.
The patch below demonstrates
one method. It uses a Noise Oscillator
to generate the chiff. A Noise
Oscillator combines a noise source and a tunable bandpass filter in one module. It can also track the keyboard, and is ideal
for our purpose. We can adjust the pitch
of the chiff, and how focused the pitch is, using just one module.
This goes through an
envelope generator to shape the attack/decay characteristics, and then through
a level control. We’ll feed the chiff
into the model at the mouthpiece.
Since the Noise Oscillator
lets us adjust the pitch of the chiff, how should we set the pitch? It turns out that most setting won’t produce
much of a chiff at all! The reason is
that the pipe itself only lets a few favored pitches through: odd harmonics, the ones that correspond to
the harmonic series of a square wave.
The first pitch the pipe
lets through is the fundamental. That’s
not a very interesting-sounding chiff, so we’ll ignore it. The second favored pitch is the 3rd
harmonic, which is three times the frequency of the fundamental, or +19
semitones. That makes a pretty
good-sounding chiff. The next favored
pitch is the 5th harmonic, which is five times the frequency of the
fundamental, or +28 semitones. Our patch
is set to the 3rd harmonic.
For added measure, we’ll
control the volume of the chiff from the keyboard velocity. The patch is below.
