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FUNCTION 5: PORTAMENTO
Portamento means a smooth glide between notes. When you play a slide flute or trombone,
you can portamento all the time. This glide effect is what you need to emulate that good ol’
theremin sound. We designed the Altura’s Portamento function to work well with the Macchiato
Mini Synth. Many synthesizers do not implement Portamento at all; some do but only in a limited
manner. Consult your synth’s documentation to find out if you can use this feature.
When the FUNCTION knob is set to 5, and Portamento Time is other than zero, the Altura
MkII sends a “Portamento ON” message (CC #65, value 127) on the currently selected Send
channel. If you send a Portamento Time = 0 message, or if you send any Pitch Bend messages,
the Altura MkII will send a “Portamento OFF” message (CC #65, value 0, current Send channel).
Waving your left hand transmits a Portamento Time message (CC #7, value 0 – 127, current
Send channel). Zero represents an infinitely short glide from note to note, which is the same
as no glide at all; that’s why Portamento Time = 0 will switch off the effect. Portamento Time =
1 means a very fast glide between notes, almost too fast to perceive. Portamento Time = 127
produces a glide about 1 second long. Intermediate numbers produce glide times along a linear
interpolation. It is an absolute time: the glide will last the same number of milliseconds whether
the interval is one semitone or six octaves. For pleasant melodic playing, use Time values of
about 10 - 25. The Altura MkII sounds most like a theremin at Time values around 30. Set the
DATA FAR knob to the slowest effect you want to hear, and DATA NEAR knob to the fastest. See
the section “PRESETS” on page 26 for a list of presets that we designed to sound most like a
theremin. How they sound on any particular synth will vary widely, so experiment!
FUNCTION 6: X-Y MODE
This function causes the right sensor to emulate the left sensor: it no longer sends Note On
messages; instead, it sends control change messages of your choosing, just like the left sensor.
You would use this mode not to create melodies, but to shape the sound already being produced
by a synthesizer. A typical use would be to assign two different filter sweeps to the left and right
sensors, or a filter sweep to one and resonance to the other.
The DATA FAR and NEAR knobs set the limiting MIDI values for the left sensor. The OCTAvE
FAR and NEAR knobs do the same for the right sensor. Use the KEY knob to select the Control
Change Number (CC#) for the left sensor, 0 – 127, and use the SCALE knob to select the
right-sensor CC#. On startup, these default to CC# 85 & 86, which are undefined. See your
synthesizer’s documentation for a table of available CC’s.
DATA
FAR
DATA
NEAR
FUNCTION
KEY
SCALE
OCTAVE
NEAR
OCTAVE
FAR
Left Sensor MIDI Max
and Min
Function
Select
Left CC#
Select
Right CC#
Select
Right Sensor MIDI Max
and Min
