The noise source is filtered and then applied to the 20 db input of the inverter/buffer where it is amplified and mixed with a DC voltage. The control output then goes to the trigger input of the function generator which drives both the VCO and VCA. Since the noise generator produces a randomly varying voltage, the function generator triggers randomly. The -5, +5 bias control is adjusted to raise the function generator to trigger as often or as seldom as you like. You can have a lot of fun with this patch and the variations are endless.
Robert Matarazzo Brooklyn, NY
WOW! Try this one, you'll really like it, but beware, you could wind up playing with this one all day synthesizing popping strings of firecrackers, percolators, popcorn popping, space wars etc.
This patch configuration uses a jillion patch cords, so get ready to count your cords before attempting this one. It sounds best played in the mid-octave range of the keyboard and requires some knob twiddling and filter and waveform adjustments. The 4730 filter would probably give a crisper sound.
Playing in different ranges with different settings can give you most any brass sound from trumpets to trombones. -ed.
Track two VCO's C below Mid C to 2nd C above Mid C
1. (a) PWM bias to full 50% tone
(b) Var. AR out to PWM to narrowest pulse.
2. ADSR VGA envelope A - 10%, D - 20%, S - 60%, R - 20%.
3. Adjust AR curve to ADSR A & D to eliminate phase difference.
4. Add narrow pulse (20% duty cycle), or ramp for softer tone.
5. BPF "Q" - 90% and ADSR var. to desired tone (around 30%).
6. Add approximately 4 Hz. control to VCO's for vibrato.
Mark Schweter Parma, OH
Straight from Dr. Frankenstein's laboratory, this effect can be heard in the sound track of any one of a number of horror films.
W. Dubois Dover, NH
Here's a way to patch the band-pass filter to the attenuator to get a truly "super Q" filter response. This could prove valuable to the synthesist using only 2720 series modules. The output of the filter is used as a feedback in the control voltage input (there are two leads for feedback because of the low level output of the filter being used as a control voltage.) Here, the attenuator serves as Q control. The only drawback is that only one control source can be used at a time. The patching configuration must be followed exactly.
Jerry Van Loh Antigo, WI
* VCA may be used in place of attenuator for a voltage controlled Q.
This patch sounds much like a honky-tonk piano if the oscillator is kept at the top of its range. Sounds even better if the keyboard output is doubled by way of the patch panel. Using both control oscillator outputs sounds as though the PWM frequency were doubled. Admittedly, this doesn't sound much like a piano at low frequencies, but it's still a funky sound!
Gary Bannister Indianapolia, IN
As an example of the subjective nature of sound; when we set this one up in our demo studio we thought it sounded a lot like steel drums before doubling the control voltage.
Here's a patch which very realisticly duplicates the take-off of a Jetliner at an airport. Even though patching is simple, adjustments need to be made to arrive at the final sound. Adjust the bias so the pitch doesn't get low enough to sound unrealistic. Adjustments of the ADSR can be changed to give different effects. Other options are putting the output through some filtering or using multiple oscillators. A 2700 series oscillator was used.
Eric Hanson Seabrook, TX
If, by chance, you don't live near an airport, and have a strange yearning to hear a Jet take-off, this patch will give you some idea of what they sound like in action. Sounds more realistic when passed through a low-pass filter at a fixed bias to pass only low frequencies. -ed.
|KBD:||High Octave, No Glide.|
|Attack : 20%|
|Variable Output: 50%|
|4781 Manual Transposer:||All VCO's tuned in unison|
|VCO's:||All VCO's using pulse output. Pulse width set to 10% to 20% duty cycle.|
|LFO#1:||* Hz. Variable output set just high enough to hear a slight vibrato.|
|LFO#2:||10 Hz. Variable output set as in LFO#1.|
|MIXER:||All signals mixed equally.|