SCHLAPPI ENGINEERING Interstellar Radio User manual

The Interstellar Radio is a faulty transmission line providing several varieties of destructive effects as
well as acting as a non-volts/octave complex oscillator when no input is provided.
Interstellar radio converts an audio signal from the input jack to a high frequency pulse train and then
back to an audio signal with voltage control over the clock for the up conversion (CARRIER) as well as the
down conversion (DEMODULATOR), like a voltage controlled radio transceiver designed for poor
reception.
Manipulating these clocks allows for a variety of aliasing, distortion, and frequency modulation type
effects. The output is also sent to a comparator along with the input, and the result is available at the
“ERROR” output for a ring modulation type effect.
When no input is provided a DC offset (controllable with the input jack) sets a frequency for the up
conversion (which is effectively a VCO), the down conversion is a form of frequency modulation acting
on the DEMODULATOR oscillator. Two audio signals can be inserted into CARRIER and DEMOULATOR IN
jacks and modulate each other in the same way.
If no external CV is applied the input signal is normalled to the two CV inputs, so that turning those
controls to the right applies additional audio rate modulation directly to the two oscillators.

Panel Controls
SIGNAL IN: Attenuates input level; If no input is connected, it changes the level of a DC bias
input allowing for standalone noise and broken radio sound explorations.
CARRIER CV: Attenuates CV input over internal clock applied to transmit (up conversion) side.
If nothing is plugged into the CV input it will apply the SIGNAL IN as audio rate
frequency modulation to the CARRIER frequency.
CARRIER FREQ: Bias frequency of the transmit (up conversion) side. Adjusting this effectively
changes your sample rate, allowing for aliasing effects. If it is too low it may not
pass any audio.
DEMODULATOR CV: Attenuates CV input over internal clock applied to receive (down conversion)
side. If nothing is plugged into the CV input it will apply the SIGNAL IN as audio
rate frequency modulation to the DEMODULATOR frequency.
DEMODULATOR FREQ: Bias frequency of the receiver (down conversion) side. If this clock matched the
CARRIER FREQ and both were set over twice the frequency of the input signal,
then the output would match the input. By adjusting this all sorts of
nonlinearities and distortion are introduced, including some effects similar to
bitcrushing. If this is set too low no output will be produced.
ERROR THRESHOLD: Sets the comparator threshold for the ERROR output. The waveform is
asymmetrical and bipolar so a center setting will be the noisiest and most
similar to the SIGNAL OUT with the two extremes being closer to the SIGNAL IN.
On certain settings this knob will be similar to a wet/dry mix (but everything is
square waves).
TONE: This controls a passive low pass filter on the SIGNAL OUT (also the PLL
demodulator loop) and can be used to tame the output as well as affect the
tracking of the signal.
TYPE: Sets the type of PLL tracking loop used to recover the signal on the
DEMODULATOR side. Changes the character of the effect.
PANEL JACKS
SIGNAL IN: Insert audio here.
OUT: This is the recovered and mangled audio, may or may not resemble the input.

ERROR: This is the difference between the input and output audio as rendered by a
comparator. Can be thought of as a type of ring modulation.
CARRIER CV: CV control over the internal clock for the CARRIER modulation process.
CARRIER IN: Replaces the internal clock with any signal that crosses zero volts of your choice.
If you plug the output of an oscillator that tracks 1V/OCT here you can play
melodies on the Interstellar Radio.
NOTE: This will disconnect the internal CARRIER clock, CARRIER CV in will no
longer affect CARRIER FREQ.
CARRIER OUT: The output of the internal CARRIER clock - a wide range non V/OCT square wave
oscillator.
DEMODULATOR CV: CV control over the internal clock for the demodulation process.
DEMODULATOR IN: Replaces the internal clock with any signal that crosses zero volts of your choice.
NOTE: This will disconnect the internal DEMODULATOR clock, DEMODULATOR
CV in will no longer affect DEMODULATOR FREQ.
RX CLOCK OUT: The output of the internal DEMODULATOR clock - a wide range non V/OCT
square wave oscillator.
SOME PATCHES TO TRY
BROKEN RADIO NOISE: Leave the input unconnected, listen to the OUTPUT while turning the CARRIER
FREQ and DEMODULATOR FREQ knobs. Try feeding in some CV. LOOP 1 or 3 will
work best for this.
MODEM MELODIES: Patch a melodic sequence to the input (triangle wave is good), mult the CV of
that melodic sequence into the CARRIER CV in and a different CV into the
DEMODULATOR CV in. Listen to the OUT.
GLITCH DISTORTION: Insert an audio source into the INPUT (triangle wave, melodic is really good),
listen to the ERROR output. Turn down the CARRIER FREQ and DEMODULATOR
FREQ until things get crunchy, feed in CV. Turning ERROR THRESHOLD will act as
a wet/dry mix.

MODEM MELODIES II: Leave the input unconnected, patch a V/OCT tracking VCO into the CARRIER IN,
you are now effectively playing the clock rate. Play a melody, turn the frequency
knob on the VCO, go low. Feed a slow LFO into the DEMODULATOR CV.
LASER DRUMS: Feed an external drum machine (or rhythmic sequence) into the SIGNAL IN.
Take output from ERROR. Start with both FREQ knobs low and start turning up
the CV knobs, turn knobs to taste. Turning ERROR THRESHOLD will act as a kind
of wet/dry mix. You may need a VCA after the Interstellar Radio with an
envelope triggered by the input or an envelope follower to get silence between
drum hits.
PSEUDO RUNGLER: You need a shift register module for this one, I used an NLC 8Bit Cipher. Patch
the oscillator OUT from the CARRIER into the DATA in on your shift register.
Patch the oscillator OUT from the DEMODULATOR into the CLOCK in on your
shift register. Take CV outputs from the shift register into the CV ins of the
CARRIER and DEMODULATOR. Lister to the main OUT of the Interstellar Radio.
Start with CV and FREQ low then turn up slowly, you should achieve a wide
variety of generative melodies and abrasive sounds.