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Quadrant 

 

A partly echoing, partly arpeggiating, possibly warped synth for the ArduTouch.

 

 
 

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IT IS RECOMMENDED THAT YOU USE ARDUINO VERSION 1.6.6. 

 
Then uncomment the "#define BUILD_166" line in Model.h of the library. 
 
Some features and/or presets may be omitted if BUILD_166 is not used. 
(In this version of Quadrant all features are present, and only the  
"FraraJaqua" preset is omitted.) 
 
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==== Audio/Control Flow Diagram for the Quadrant Synth ==== 

 
 
              ------------   
              |  Tropes  | --------. 
              ------------         | 
                                   |     
                                   v     
                            ---------------- 
             .----------->  |   Echotron   | 
             |              ---------------- 
             |                  |     | 
             |------------------|-----|------------------.  
             |                  |     |                  | 
             |                  v     v                  v 
        ------------        ---------------        ------------ 
        |  Lead 0  |  --->  |    Mixer    |  <---  |  Lead 1  | 
        ------------        ---------------        ------------ 
                                |     | 
                                |     | 
                                v     v 
 
                             [ Audio out ] 
 
 
Lead 0 is duplicated in the opposite audio channel by Lead 1 (which 
may be transposed and/or detuned from Lead 0).  The note information 
for Lead 0 is also fed into the Echotron.  At the same time, a "trope" 
(an arpeggiation pattern) can be applied to the echoed note.  The 
output from the Echotron is internally panned in stereo and then fed 
into a mixer along with the audio output from Lead 0 and Lead 1. 

 

 

Summary of Contents for Quadrant

Page 1: ...ly the FraraJaqua preset is omitted Audio Control Flow Diagram for the Quadrant Synth Tropes v Echotron v v v Lead 0 Mixer Lead 1 v v Audio out Lead 0 is duplicated in the opposite audio channel by Lead 1 which may be transposed and or detuned from Lead 0 The note information for Lead 0 is also fed into the Echotron At the same time a trope an arpeggiation pattern can be applied to the echoed note...

Page 2: ...ecrease by an amount controlled by the FEEDBACK setting If FEEDBACK is set to its highest value 255 then the note will echo forever or until all the slots in the carousel have been used up and a new incoming note overwrites it Each time a note echoes its pitch can be raised or lowered by the current WARP FACTOR The number of slots in the carousel is configurable and can be set interactively via th...

Page 3: ...tes currently echoing in the carousel and ISO TEMPO is on then the delay time will be 1 4 of what it would be if there were only 1 note in the carousel The Telepromt and Frara Jaqua presets use ISO TEMPO You can toggle ISO_TEMPO via the Parameter Menu see below ENVELOPE A master envelope dynamically controls the amplitude of the notes produced by the Echotron This envelope is a traditional ADSR At...

Page 4: ... pots see below PAN CONTROL A PAN control dynamically rotates the note output in the stereo field The DEPTH and FREQ of the panning can be controlled via the pots see below Overview Diagram of the Echotron Now that we have covered each component here is an overall view HOLD notes in SAMPLE HOLD v WARP Trope in Note Carousel DELAY ISO TEMPO FEEDBACK SLOTS ENVELOPE notes out Attack Decay v Sustain S...

Page 5: ... blue LED for right button will change state from OFF to ON to BLINKING back to OFF etc Below is a chart showing which pair of parameters the pots control when the LEDs are in a given state red LED blue LED top POT bottom POT OFF OFF echo WARP echo DELAY time ON OFF echo FEEDBACK lead echo BALANCE BLINK OFF panning FREQ panning DEPTH OFF ON autowah FREQ autowah DEPTH ON ON autowah CUTOFF echo PULS...

Page 6: ...cally exited restoring the prior user interface state You can exit the Parameter Menu without modifying any parameters by double tapping the left button a second time The list below describes what actions are taken when a key is pressed Key Action C toggle Sample and Hold on off C turn Sample and Hold off and unhold all held notes D hold next note played D reserved E toggle lead voices on off F se...

Page 7: ...ces off and should stay off D Farsy E Teleprompt lead voices off turn them on once 2 slots are playing F Glacial play very slowly G Blur A ToneJack B FraraJaqua lead voices off turn them on once 4 slots are playing FraraJaqua only available when compiled with build 1 6 6 Types of button presses Tap quickly tap a button Press long press a button Double Tap quickly double tap a button ...

Page 8: ...square wave oscillators which can only be set to frequencies which have integral wavelengths The frequencies produced by these oscillators conform more closely to a scale in Harmonic Tuning than one in Equal Temperament But why does the C key play an F The short answer is that on the ArduTouch whose audio rate is 15 6 kHz F in octave 1 has a period of 360 samples 360 is a number favored by the anc...

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