This project will only be funded if it reaches its goal by .
Percussa Super Signal Processor Eurorack Module
Percussa Super Signal Processor Eurorack Module
A eurorack module based on one of the fastest ARM processors available, the quad core Cortex A17, and high end ADC/DAC converters.
A eurorack module based on one of the fastest ARM processors available, the quad core Cortex A17, and high end ADC/DAC converters. Read more
This project will only be funded if it reaches its goal by .
About this project
See further down below for additional stretch goals! Thanks for backing!
The Percussa Super Signal Processor (SSP) Eurorack Module is a powerful Eurorack module by Percussa, a brand of Noisetron LLC. It is based on one of the most powerful quad-core ARM Cortex A17 processors currently available, running an optimized linux mainline (v4) kernel, custom DSP software and professional audio I/O drivers.
Listen to the audio demo above (called Picard's Dream), recorded on our functional prototype: wavetable oscillator with manual tweaking and modulations using LFO and EG, with global delay and reverb section enabled, recorded directly to SD card.
The above demo (Conversation II) was made by request from backers and eurorack enthousiasts, to show what can be done with the step sequencer module. Some info on the demo: 2 sequencers, 1 Wavetable Osc, 2 LFOs, 1 EG (ADSR). The first LFO modulates the Z parameter of the wavetable osc, 1 sequencer modulates freq of the wavetable osc and triggers the ADSR while the other sequencer modulates freq/amp of the other (second) LFO. Manual tweaking of the first LFO frequency, sequencer pattern length, tempos, as well as live editing of sequencer steps. Also experimentation with cloud/spread feature of wavetable osc and manual tweaking of XY parameters of the wavetable oscillator. Sound passes through global delay and reverb section. You can find more demos below.
Key Features & Specifications
- 8 outputs via high end AKM DAC with 32 bit resolution / 192kHz sample rate (AK4458)
- 2 inputs via high end AKM ADC with 32 bit resolution / 192kHz sample rate (AK5552)
- Support for eurorack DC voltage level ranges on inputs and outputs (-5V to +5V)
- Low-noise power supplies and op-amp stages, featuring 0.1% resistors
Control Voltage I/O
- 14 inputs via industrial ADCs or via AKM audio ADCs (see “status of project” section)
- Support for eurorack DC voltage level range (-5V to +5V)
- Quad core processor running at 1.8 GHz per core 32-bit SIMD and 64-bit floating point arithmetic
- 32-bit floating point ADC/DAC input / output
- Capable of running multiple software modules in parallel on multiple cores
- Supports recording audio inputs and outputs directly to SD card for instant wavetable / sample creation or recording of live performances without the need for external software
- Supports loading your own WAV files into the Wavetable Oscillator and Sampler software modules, via the SD card (limited only by SD card size / RAM size)
- Coarse and Fine frequency controls on all Oscillators
- Comes with a set of 100+ pre-recorded samples / wavetables
- Storage and Recall of Presets and Settings with the press of a button
- Rule-based fast 2D patching
- Supports routing / mixing multiple inputs to multiple software modules
- Supports routing / mixing multiple software modules to multiple outputs
Included DSP modules (see stretch goals for additional modules)
- Wavetable Oscillator with true 3D morphing (XYZ) and cloud features
- Sampler with Layering features
- LFO with multiple waveforms (sine, saw, square, triangle)
- Variable Frequency Noise
- DC generator
- Enveloped Generator with Exponential A and DR
- Comb Filter
- State Variable Filter
- Step Sequencer
- SDK with examples for writing your own modules in C++
- Support on the SSP to load your modules from the SD Card
Display, Graphics and User Interface
- 1600x480 pixel wide format full colour LVDS IPS display
- 2D & 3D Graphics acceleration support (see stretch goals)
- 4x High quality Aluminium Machined Knobs
- 4x Bourns Endless and Click-less Encoders
- 18x Industrial Temperature MEC Switches
- User interface design featuring shallow menus (no menu diving), large fonts for readability and signal input / output Oscilloscope features
- 1 USB device port with USB Audio Class 2.0 support
- 1 USB host port with USB MIDI class and USB ethernet adapter support
- Serial (header) connector on PCB to access linux serial console
- 1 microSD card slot 16 GB professional microSD card (not included in DIY pledge) with FAT partition for easy sharing of presets and samples and for software updates (OS agnostic)
- 2GB onboard RAM
Dimensions and Front Panel
- 60HP width, 3U in height (eurorack compatible, see pledges for customization options)
- 50mm depth behind front panel (estimated)
- 2mm thick CNC machined / laser cut aluminium front panel, sandblasted and black anodized (see pledges for customization options)
- 350mA @ +12V and 50mA @ -12V consumption (estimated)
- Standard 16-pin eurorack power connector
Moog mother-32 modulating Wavetable Oscillator XYZ via Stereo Audio Inputs on functional prototype w/ manual tweaking of cloud features (sound output to speakers and recorded by camera).
Modulating Wavetable Oscillator XYZ via internal LFOs (sound recorded directly to SD card on functional prototype and synced to video in post).
Modulating Wavetable Oscillator XYZ via internal LFOs w/ tweaking of cloud features (sound output to speakers and recorded by camera).
Recording sound via stereo input of functional prototype to SD card and then loading it into the wavetable oscillator for playback (the sound you can hear in the video is output to speakers and recorded with camera).
Why this powerful Eurorack module?
The Percussa SSP module offers the processing power of roughly 10 digital eurorack modules:
Common processors in Eurorack modules are the single core Cortex M4 and M7 processors, which at their highest clock frequencies of around 200MHz stay below 500 DMIPS. Some eurorack modules have started using more advanced processors, for example the single core Cortex A8 at 1GHz, which offers around 2,000 DMIPS of processing power.
In contrast, the quad-core ARM cortex A17 platform, used in the Percussa ENGINE (part of Synthor System 8, a digital modular synthesizer), provides over 20,000 DMIPS of processing power, with its 4 cores running at 1.8GHz.
Such computation power allows the user to run DSP algorithms at higher sample rates, enabling better quality sound, or run multiple modules in parallel, saving the user space in his or her eurorack system and providing a simple and uniform user interface to multiple modules.
Based on our tests with the Percussa ENGINE, we estimate the SSP will be able to run 8 wavetable oscillators, with the unison / cloud feature set to 8, which means that it is effectively running 64 oscillators in parallel, with the global Reverb and Delay section enabled.
We will make a C++ SDK available as part of this project and will strive to foster a community of people who want to create custom modules.
What is the status of the project?
The Percussa SSP module is currently a functional prototype, based on the existing Percussa Engine and Remote products (currently selling and introduced at the Winter NAMM 2017 show). The platform works, has been tested the past months and runs the software of the Percussa Engine, but does not feature all the input and output jacks yet that will be on the module.
The prototype consists of several PCBs: carrier board with audio DAC/ADC, MIDI, SD card slot and USB host/device ports and LVDS connector, and power supplies, ARM SoC system on module PCB, encoder and knob PCBs and USB-encoder adapter board. The encoder/button/adapter boards are connected via flat cables while the adapter board/carrier board connects via USB. The display module installs onto the carrier board via FPC cable.
The SSP module which we will ship to the backers will consist of the same carrier PCB design which is currently used for the Percussa ENGINE, but will come with the following modifications:
- 4 encoders and 18 buttons will be directly integrated onto the carrier PCB to make the module more compact and so it fits within 60HP of eurorack space.
- The 9x ¼ jack connectors at the top right will be removed from the carrier PCB and will be replaced by 24x 3.5mm jacks on the right side of the PCB (where the system on module is now) - those 24 jacks will offer 14 CV inputs, 2 audio inputs and 8 audio outputs.
- For the CV inputs, we will add additional ADCs and input / output stages. The ADCs can be connected to the SPI or the high speed USB host port of the ARM SoC. Preliminary tests show we have both options. If further testing of the USB to I2S/TDM bridge we intend to use provides satisfying results we will use the USB host port and use the same AKM ADCs as used for the audio inputs, offering 192 kHz / 32-bit sample rate / resolution. Otherwise we will opt for an industrial ADC connected via SPI, capable of 40kHz / 16-bit sample rate / resolution, as is commonly used for CV inputs in eurorack digital modules.
- ARM SoC system on module will be relocated to the back of the carrier PCB.
- 2 USB host ports will be removed since one will be used to connect additional onboard I/O and the other is the same port as the device port, leaving 1 remaining USB host and 1 USB device port available to the user
- MIDI in/out/thru ports (DIN-5 connectors) will be removed from the PCB, since most MIDI controllers now are USB devices without MIDI ports.
- Headphone amplifier will be removed from the PCB
- A vertical (perpendicular to the PCB) microSD slot will be used instead of a large SD slot flush with the PCB.
- Power supplies will be revised and updated so the module can be powered by the eurorack power rails.
Besides these hardware modifications, we will update the sound synthesis software currently running on the Percussa Engine, with a new graphical user interface design, and will tailor its menu system to work optimally with the encoder and button layout of the Percussa SSP module (see below).
In-depth description of Percussa SSP Module
A detailed overview of all specifications can be found at the top of the page. Below we describe the main parts of the module:
1) Widescreen Display and Input/Output Ports
The SSP module comes with the same 1600x480 IPS display (full colour, NOT A TOUCHSCREEN) as used on the Percussa ENGINE synthesizer, and will feature one USB host and one USB device port, in addition to the microSD card slot used for starting the module and storing user data.
A professional grade microSD card of 16GB size, with software, will be included with all units shipped (except in the case of the DIY KIT, where the backer will have to buy and flash their own microSD card). Software will be upgradeable through the microSD card.
2) DSP Algorithms (software modules)
The same DSP algorithms which are used on the Percussa ENGINE, and which are used in the videos and sound recordings below, will be used on the SSP module.
Below you can find some audio examples recorded directly to SD card on the Percussa Engine, at 192kHz, 32-bit resolution and then encoded using Audacity to MP3, 320kbps VBR ("insane" export option).
The first example features 15 oscillators running in parallel, with realtime tweaking. the oscillators are slightly detuned and are passed through the global delay and reverb section. The second example features a combination of modules such as LFOs, wavetable oscillators, waveshapers, noise generators, etc.
One of the main software modules of the platform, the digital wavetable oscillator, is capable of chopping up the samples you load dynamically to create different wavetables. It supports true 3D morphing of the wavetables, which can be modulated either internally using other modules (LFOs, EGs, …) or through the audio / CV inputs.
You can see a demo of the wavetable oscillator in the video below. The oscillator also comes with a unison/cloud feature which thickens the sound by duplicating the oscillator up to 16 times with a pitch offset (spread) which can be modulated internally or via the CV/audio inputs.
Outputs of software modules can be routed to multiple output jacks and signal inputs can be mixed together and routed internally to multiple software modules.
Using the audio inputs, the user can record samples to the SD card, just like in the case of the Percussa ENGINE (see video gallery for a demo of the sampling feature). These samples can then immediately be loaded into the wavetable oscillator or sampler software modules without requiring any external software running on a computer. The software supports cropping and normalization features for simple editing and supports recording the main audio output, which is also useful for recording your live performances.
The following software modules will be included in the Percussa SSP. These modules are already working and available on the Percussa ENGINE:
- Wavetable Oscillator with true 3D Morphing (XYZ) and Cloud (Spread) features
- LFO with Saw, Sine, Square, Triangle,
- Step Sequencer with 64 Steps per Pattern, Length and (MIDI) Sync features,
- Comb Filter,
- Sampler with Individual Triggering and Layering features,
- Variable Frequency Noise Generator,
- State Variable Filter (SVF),
- Envelope Generator (EG) with exponential A and DR,
- Global Reverb and Delay Processors
3) DSP routing / modulation system
The Percussa SSP will feature the same modulation system as used in the Percussa ENGINE, where the user is able to insert modules in a 2D grid, and set rules for which modules will accept modulation and which modules will modulate other modules. This modulation system is a 2D extension of the 1D “rack” or “signal chain” system popular in some DAWs and software synths, and enables fast patching.
4) User Interface of SSP module
The UI of the Percussa SSP will use the same philosophy of the Percussa ENGINE, where only one “level” of menus is used, to avoid menu diving. Additionally, the encoders and buttons will be placed around the screen to improve usability.
Currently there are 4 editors on the Percussa ENGINE which will also be present on the SSP module: the Processor, Global, Modulation, and Recording Editor. One additional editor will be added to the software for the SSP, the Network editor, which will provide an overview of the 2D grid with modules.
- Sep - ordering parts
- Oct - PCB design
- Nov - first prototype assembly and testing
- Dec - Software engineering
- Jan - second (final) prototype assembly and testing
- Feb - Software engineering + order front panels
- Mar - assembly of final units
- Apr - shipping early pledges
- May - shipping normal pledges
Taxes and Duties
If you are located outside the United States, please note that import duties, taxes or VAT is not included in the pledges. When your shipment clears customs, you (the backer) might be liable for paying import duties or taxes to the customs office in your country.
If you are located in California, please note that sales tax is not included in the listed pledges, and depends on the county / city we are shipping to. At the time of shipment, we will calculate the correct CA sales tax and send you an email with a secure payment link asking you to pay the correct sales tax amount for the address we are shipping to.
Outside California, within the United States, sales tax is the responsibility of the backer.
The HS code for customs classification of the module will be 9209.94.80 00 (parts for musical instruments for which the sound is produced electronically).
- $35,000 - MIDI MPE Support
- $45,000 - Extra software module group #1 ***
- $55,000 - Extra software module group #2 ***
- $65,000 - Extra software module group #3 ***
- $75,000 - Extra software module group #4 ***
- $100,000 - LuaJIT module to write your own DSP modules in LUA, directly on the SSP, using a USB keyboard attached to the SSP's USB Host port.
- $120,000 - 3D acceleration support in the C++ SDK giving you access to the GPU on the quad Cortex A17 processor using OpenGL ES.
**** The extra module groups listed above consist of 5 modules each, 2 of which are more advanced modules and 3 of which are simpler modules. Each time the stretch goal is reached, the modules to be developed will be announced.
Examples of advanced modules (non exhaustive list):
- Steiner Parker Filter (SPF)
- Virtual Analog Oscillator
- Membrane Physical Model
- Spectral Oscillator
- Percussion Oscillator
- Filter Bank
Examples of simpler modules (non exhaustive list):
- Ring Modulator
- Simple Delay Line
This kickstarter project would not have happened without the support of close friends in the electronic music and music technology communities, and enthousiastic eurorack users. You know who you are.
Risks and challenges
The main challenges of the project consist of:
1) adding CV input jacks, input stages for the CV signals, and ADC conversion chips for the CV signals to the existing schematics and layout
2) relocating the main processor module, and re-routing the PCB layout where necessary
3) updating the power supplies to use the eurorack power rails
Given our background, our history of shipping multiple products since 2004, and the experience we've built up with designing, developing, prototyping and manufacturing the Percussa ENGINE, and reaching our deadline for the 2017 Winter NAMM show in Anaheim where we first showed the ENGINE and Synthor System 8, I'm confident we can bring the project to a good ending and deliver on time.
PCB layout and schematics, as well as software development, is being done in house by the founders of Percussa, Bert and Celine, with assistance from embedded linux specialists and analogue electronics design engineers.
Once the project gets funded, PCB schematics and layout design will begin immediately. The project allows for 2 revisions of prototypes, which should be adequate given the Percussa Engine only went through 2 revisions before it came to market.
Parts will be ordered shortly after the projects get funded, to avoid production delays.
Building prototypes and manufacturing the units will be done by Percussa's subcontractors which we have worked with since 2004.Learn about accountability on Kickstarter
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