What is a prototype?

A prototype is a preliminary model of something. Projects that offer physical products need to show backers documentation of a working prototype. This gallery features photos, videos, and other visual documentation that will give backers a sense of what’s been accomplished so far and what’s left to do. Though the development process can vary for each project, these are the stages we typically see:

Proof of Concept

Explorations that test ideas and functionality.

Functional Prototype

Demonstrates the functionality of the final product, but looks different.

Appearance Prototype

Looks like the final product, but is not functional.

Design Prototype

Appearance and function match the final product, but is made with different manufacturing methods.

Production Prototype

Appearance, function, and manufacturing methods match the final product.

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Prototype Gallery

These photos and videos provide a detailed look at this project’s development.

About

Programmable USB/DSP Module

The FlexFX module is only 1.0" x 1.4" and supports USB Audio and MIDI, 32/64-bit DSP, up to 32 USB and ADC/DAC audio channels, up to 192 kHz sampling rates, and input to output latency of 350 microseconds. Modules can be updated with pre-built effects or custom designed effects at any time using standard USB/MIDI.

FlexFX can simultaneously act as a USB/MIDI controlled effects processor, a direct-input interface for recording to USB, and a USB audio output sound card to serve as an audio interface for powered monitors or for mixing effects and USB audio together (e.g. jamming to music and while playing). 

USB/MIDI can be used to customize each effect preset allowing you to tweak and store for later recall. You can also hook up potentiometers and switches using I2C controlled ADC's and GPIO expanders to control volume, tone, preset selection, bypass and other effects modes, and LED's.

Hardware and Firmware Features

  • USB Audio Class 2.0 compliant for audio streaming and MIDI supporting effects control, data loading, and user interfaces.
  • Safe firmware updating using USB/MIDI.
  • Up to 32x32, 16x16, 8x8 USB audio and I2S in/out at 48/44.1, 96/88.2, 192/176.4 kHz sample rates.
  • Support for I2S 8-slot TDM and up to four separate ADCs and four separate DACs.
  • Single audio cycle DSP processing for all 32 channels (e.g. audio block size = 1) with a system latency (I2S input to I2S output) of 16 audio cycles (16/Fs, less than 85 microseconds at 192 kHz).
  • I2C interface (for peripheral control) and general purpose input/output signals (GPIO).
  • Free application development kit supporting USB audio/MIDI, ADC/DAC input and output, I2S and PCM configuration.
  • Hand optimized digital signal processing functions for FIR/IIR filters, scalar and vector math, convolution, interpolation, etc.

Free High Quality Effects

Free quality guitar/audio effects are available (full source code) via the FlexFX development kit. All of the effects support knobs (potentiometers) for volume, tone and preset selection. Presets can be recalled using the 'preset' knob or via USB MIDI commands and can be 'tweaked' using a graphical user interface via USB MIDI (Google Chrome required).

  • Amp and cabinet simulation using impulse responses. A tube amplifier model and tone stack followed by up to 40 milliseconds of impulse response processing. Effect parameters for amplifier drive, bass boost/cut and center frequency, midrange boost/cut and center frequency, treble boost/cut and center frequency, power supply sag, output volume, and cabinet impulse response selection. Up to five presets.
  • Three-stage tube preamp overdrive model with customizable preamp responses and dynamics per preamp stage. Internal DSP processing at 12x oversampling (i.e. at 576 kHz) using 32/64 bit math functions.  Effect parameters for input drive, pre-stage bass cut, post-stage treble cut, slew-rate limiting, stage gain, triode/tube bias points, and output volume. Up to five presets.
  • Combination delay/chorus/flanger supporting variable LFO frequency, variable delay, feedback adjustment, tone filtering, and wet/dry blending. Parameters for input drive, delay time, LFO rate, modulation depth, parametric filter frequency and Q-factor, wet signal diffusion, feedback level, wet/dry mix and output volume. Up to five presets.
  • 15-band graphic equalizer with -12dB cut to +12dB boost per band. Up to five presets for EQ band cut/boost levels and output volume.

Guitar Interface Board

  • 1.0" x 1.5" and stackable with the FlexFX USB/DSP module
  • 24-bit 192 kHz 115 dB SNR fully differential analog to digital converter
  • 24-bit 192 kHz 115 dB SNR fully differential digital to analog converter
  • Input: Mono high-impedance (1 Mohm), 1 Vrms (2.8 Vp-p) max
  • Output Mono low-impedance, 1 Vrms (2.8 Vp-p) max
  • 4-channel analog to digital convert for four pots/knobs
USB/DSP Module and Guitar Interface Stacked
USB/DSP Module and Guitar Interface Stacked

Custom Application Development

Guitar/audio effects and custom effect programming support are all provided by the free FlexFX development kit.

Customization FlexFX development Kit

https://github.com/flexfx/flexfx.github.io

XMOS Compiler and Linker

xTIMEcomposer is freely available from www.xmos.com

FlexFX User's Forum

https://flexfx.discussion.community

Risks and challenges

No feasibility risks at this stage of the project. The PCB's have been prototyped and the development kit is stable. The USB, MIDI, I2S, DSP, I2C functions and the audio effects applications are in working order.

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Support

  1. Select this reward

    Pledge US$ 50 or more About US$ 50

    FlexFX USB/DSP Module

    The brains of the FlexFX kit. Small (1.0"x1.4") yet powerful with up to 2000 MIPs. Supports USB Audio Class 2.0, DSP processing, USB MIDI control, and I2C peripherals, I2S/PCM audio. Programmed with the free FlexFX firmware development kit.

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  2. Select this reward

    Pledge US$ 50 or more About US$ 50

    FlexFX Guitar Interface

    Very low noise and low latency mono guitar interface. One high-impedance input and a low impedance output both using differential analog signaling for ultra low noise. Has connections for guitar in, instrument out, ground, and four potentiometers (knobs).

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  3. Select this reward

    Pledge US$ 90 or more About US$ 90

    FlexFX Module + Guitar Interface

    One USB/DSP module and one guitar interface. Can be stacked to create an extremely small high performance programmable guitar FX processing system.

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    Estimated delivery
    Ships to Only certain countries
    22 backers
    $

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Funding period

- (30 days)