boourns / spectrum

AudioUnit ports of popular open source eurorack modules

Spectrum

AudioUnit ports of popular open source eurorack modules

Available on App Store for iOS: https://apps.apple.com/us/app/spectrum-synthesizer-bundle/id1467384251

Building

Spectrum depends on two other git repositories to build: BurnsAudioCore and BurnsAudioUnit. The Spectrum xcode workspace expects these three git repositories to all be siblings in a directory. So for example,

mkdir auv3
cd auv3
git clone [email protected]:boourns/Spectrum.git
git clone [email protected]:boourns/BurnsAudioCore.git
git clone [email protected]:boourns/BurnsAudioUnit.git
open Spectrum/Spectrum.xcworkspace

Exploring the code

Each AudioUnit is broken down into the following components. You can find the code under the Instrument subdirectory. Audio Units with both an Effect and an Instrument version have a Shared folder holding the shared code. For example, here is the code for the Spectrum instrument.

AudioUnit.mm / AudioUnit.h (Objective-C)

Root AudioUnit class. Responsible for parameter registration, initializing and managing buffers, instantiating the C++ "kernel" where the DSP code is written. The internalRenderBlock callback is in this class, which the host calls for every render block.

ViewController (swift)

Provides the UI for the Audio Unit. The parent class, BaseAudioUnitViewController, is provided in BurnsAudioCore and handles connecting the UI to the Audio Unit instance.

Kernel (C++)

The exciting DSP code. Reads/writes parameter values into the C++ engine, contains the DSP render block. In our case it mostly manages the Mutable Instruments code and calls those DSP engines.

There are many independent, reusable components available in the other repositories, for example helper classes for initializing AudioUnit buffers, a tempo-synced LFO, or a MPE-capable MIDI processor / voice manager in BurnsAudioUnit.

License

MIT

spectrum's Issues

Matrix UI: support ~10 rules

garageband, modal and resonator not getting MIDI

ui pattern for hidden settings

• "fake modal" view

actual app contents

XY UI doesnt change with MIDI

does it on AU?

sustain pedal midi CC support

spectrum: pitch knob busted

Modal: L/R with no Space is weird

elements: add input as mod source

just have it for instrument too to keep them in sync

TUNING

plaits: amp ADSR is a lie

silver TODO list

silver TODO

• deployment
• logging

plaits: check unison pan spread

xy modulation via au parameters

does it work?

clamp gain modulation from 0 to 1

otherwise its a shitty ring mod

clouds: input gain

modal/resonator/granular: is pitchbend getting set to 12?

Spectrum: smooth changes to right/left gain

env cuts off decay stage if gate goes low

Use the value to text converter for the UI

Then in the kernel we can use LFO rate strings and, say, specify the chord type in chord mode.

rings: stereo spread parameter

NanoStudio2 load project has no matrix mappings

volume: clouds too low, plaits too low with polyphony

sync LFO to host tempo, key sync, reset phase

clouds: v/oct in is too slow

clouds internally processes floats, remove short conversions

@

write manuals / website

add MIDI mapping to manual

portamento - range is poor, use doubles

Make XY Pad same CCs on all units

clean up parameter groups

left/right output -> output & spread

integer knobs

presets

randomize?

aftertouch, sustain pedal CCs

clouds modulation targets dont work

left/right source: middle default

clouds: gate mapping

modal is too loud, louder than spectrum

new icon

scrolling through pitch parameter can cause it to jump really high pitch

licenses

rename plugins

unique icons

fx are not working

modal: volume too high?

plaits can lose voices

clouds env-> level no work

elements: aumf version