About this project
With some coding and DSP knowledge, the OWL can become any kind of audio effect that you can imagine. Effects can be combined in any number of ways by chaining or switching between them.
Using a provided C++ framework, effects can be developed, compiled and loaded to the on-board ARM Cortex M4 chip with no proprietary tools or hardware-specific knowledge.
The OWL gives coders the chance to implement their own effects and become part of an open-source audio developer community. For those who don’t write code there is a growing collection of patches available for immediate download and use in the patch library.
With a strong emphasis on open-source hardware and software, the OWL is perfect starting point for anyone wanting to experiment with embedded audio, or for those wanting to to learn more about audio programming and Digital Signal Processing in general.
- Load patches from your computer via USB
- Collection of sample patches available and growing
- Standard guitar pedal inputs/outputs
- Write code for a hardware DSP architecture in plain C/C++
- no hardware specific coding required
- Open source platform and tool chain
- Access to all low level ARM functions
Implement this class to create your own Patch. Call getParameterValue() to get a knob position. The processAudio() method is called on each audio block.
A simple Gain patch that multiplies each sample by a value between 0 and 1.
Test your patches with the Owl Simulator
We developed a C++ project called the Owl Simulator (OwlSim), that makes it easy to test your patch. The OwlSim uses the Juce library and is cross-platform (Mac / Windows / Linux). Put your patch in the OwlSim and you will be able to run it as a VST/VSTi/AU in your favorite DAW (Reaper, Logic, Live, Nuendo, Ardour...). The OwlSim allows easy testing, debugging, or just being able to run your favorite patches on your computer for a home studio session !
- 168MHz 32bit ARM Cortex M4
- 1mb RAM, 1Mb Flash memory
- Integrated DSP, FPU, DMA
- 12bit / 96kHz codec
- 4 assignable control knobs
- Bypass switch
- Indicator led
- Mono Jack input (6.35mm = 1/4 inch), unbalanced, Z=1MΩ
- Mono Jack output (6.35mm = 1/4 inch), unbalanced, Z=1kΩ
- 9V DC power socket
- mini USB for patch upload
As we've hit all our stretch goals, all OWLs also include
- Expression pedal or switch input jack
- MIDI control via USB
- Hardware codec
- Push button bi-colour LED
- Stereo Input/Output
- 1mb of RAM
+ £12,000 Expression Pedal / External Switch - funded
We will add an input jack to connect an expression pedal or an external switch. Control moving filters, wah effects, or tap tempo by foot!
+ £16,000 USB MIDI - funded
We will implement MIDI over USB functionality. This will allow you to control patch parameters from external MIDI controllers, or send MIDI signals from the Owl to other devices.
+ £20,000 24bit Codec - funded
A high-resolution 16/24 bit 96kHz hardware codec will be integrated for input and output processing.
+ £24,000 Push button bi-colour LED - funded
An extra push button mounted on the surface to allow more control. The switch will contain a bi-colour light emitting diode for visual feedback.
+ £28,000 Stereo Input / Output - funded
Another input and output will be added to allow stereo and dual mono effects. Great for delays, reverbs, dual effects and advanced signal routing!
+ £30,000 Memory Extension - funded
If we reach this target we will increase the amount of available memory to 1Mb RAM.
We believe in open source and open hardware, and hope that publishing the OWL source code and hardware designs will encourage you to get involved with the process of creating awesome technology. All our source and documentation is published under the Gnu GPL and is available here on github. Pull requests welcome!
The OWL is being made by Rebel Technology, a well respected and established synthesiser manufacturer on the modular scene.
Risks and challenges
Having already developed electronics and software products, and having designed a working prototype of the Owl, we know that we will be able to deliver the project as planned. We will produce the Owl at a rate of 100 units per month for the first batches. The following problems could occur after the campaign:
- Parts availability and sourcing the necessary parts and custom components.We have developed great relationships with all our providers, most of whom are local, but shortages and delays may still happen. For critical components we have several sourcing options, and smaller delays will be absorbed in our time margins.
- Although we allowed plenty of time for pre-production, unexpected hardware design issues might delay the production by a couple of weeks.
In C++, we've been using GCC ARM embedded, found here https://launchpad.net/gcc-arm-embedded
Our current scheme is a compile, drag and drop model. You simply compile the
code and then drop the generated file onto the device, just like onto a USB stick.
Linux, Mac OS X and Windows.
12 bits represents about 70dB of dynamics, which is pretty good for most effects. Having a simpler design helps keep the costs and risks down. However if we reach our Kickstarter push targets, we will add a high quality 24 bit external codec.
Yes, but you will need to use an external microphone preamplifier to get a decent signal into the pedal (and to provide phantom power if using a condenser mic).
It runs at 168MHz and is capable of performing most operations in a single cycle, including floating point arithmetics and Multiply and Accumulate. At 48kHz sampling frequency it can perform more than 3500 cycles per sample. For reference, a 7-band EQ can be implemented on this chip using 299 cycles per sample.
Is it worth putting a two-digit LED display and a knob for selecting programs or does that make it a lot more complex?
It is possible to program either effect-chains, or a program that contains several patches which you can switch between using one of the assignable pots.
We have a push target to implement MIDI control over USB to extend the interface control options.
Will be available on the PCB!
A jack input for an expression pedal is also planned as a Kickstarter push target, along with extra ADC headers on the PCB for the hardware hackers.
Yes, it’s a Kickstarter push target!
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