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A revolution in audio communications. The surround sound card (for the Raspberry Pi) which seemed impossible, but now it is done !
A revolution in audio communications. The surround sound card (for the Raspberry Pi) which seemed impossible, but now it is done !
A revolution in audio communications. The surround sound card (for the Raspberry Pi) which seemed impossible, but now it is done !
150 backers pledged AU$ 14,404 to help bring this project to life.

About this project

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Audio Injector Octo multichannel sound for the Raspberry Pi

AU$ 14,404

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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.

6ac5eb5acb7960dff0441212db13ab7e original

Prototype Gallery

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

Audioinjector Octo surround sound card for the Raspberry Pi

We bring to you the audio card (for the Raspberry Pi) which seemed impossible, but now it is done! Push your projects further into un-trodden territory - further then others have gone before.

Whilst this gadget works with the Raspberry Pi, it represents an innovation in the realm of embedded systems. The innovation is at a hardware level, in audio signalling, giving us the ability to retrofit these systems with more then their typically quoted two channels of audio in and out.

Audioinjector Octo sound card - RCA breakout
Audioinjector Octo sound card - RCA breakout

This sound card features crystal clear 8 channel output audio, with 6 channels of input audio. Unlike other multichannel solutions, this surround hat only uses the GPIO I2S bus for audio. It doesn't use USB nor does it use HDMI.

Audioinjector Octo sound card - powered balanced breakout
Audioinjector Octo sound card - powered balanced breakout

It has the capacity to provide powered balanced lines because the system is differential. This image shows the professional level output balanced breakouts. A similar board with provided for the six input balanced lines. 

          
Audioinjector Octo sound card - make your own breakout.
Audioinjector Octo sound card - make your own breakout.

The sound card is designed to be customisable. You can design your own break out to suit your needs. The break out headers are available on github as a KiCad project to aid your designs.

Our previous kickstarter success was delivered on time, working and with support. Support this campaign which builds on the same foundation.

For a scoop on the story behind this product, check this XDA post.

Stretch goal #1 at $10 000 (done)

Our first stretch goal (now achieved) will improve performance by introducing a second clock oscillator. This second oscillator will give improved performance at particular sample rates.

Stretch goal #2 at $12 000 (done)

Open hardware the RCA breakout boards. We have pushed to github the KiCad schematics and PCB layouts for the RCA breakout board. This will be a good reference if you want to design your own line breakouts.


Stretch goal #3 at $14 000 (done)

Open hardware the balanced line breakout boards. We have pushed to github the KiCad schematics and PCB layouts for the TRS breakout boards. This will be a good reference if you want to design your own balanced line breakouts.

Stretch goal #4 at $16 000

We will provide 3D printable panel templates (possibly on thingyverse). You will be able to print these panel plates to use in boxing your awesome devices !

Stretch goal #5 at $20 000

We will provide you with physical aluminium panel plates as part of your delivery ! Nothing beats the real deal ! Shipped to your door.

How do you use it ?

Nothing fancy, just plug it in and set it up like you would any other GPIO sound card. It is setup to run out of the box as the default sound output and input. That means that all of your applications will use it by default.

Example applications

  • Professional audio recording (with 6 balanced inputs)
  • Multichannel output for your projects.
  • Car audio front/back fading.
  • Active crossovers, up to 8 way, or 2 speakers each 4 way.
  • SDR, processing many channels at the same time.
  • Surround sound output for your media centre.
  • Projects we didn't imagine you would implement !
Implement Active Crossovers
Implement Active Crossovers

 

For a home theatre, plugin to your surround sound amplifier.
For a home theatre, plugin to your surround sound amplifier.

 

Auto front rear fading using GPIO control (suggested by Paul & inspector71)
Auto front rear fading using GPIO control (suggested by Paul & inspector71)

Stretch Goals

As we have made our goal, we would like to introduce some stretch goals. If you haven't heard, stretch goals are new goal targets which (if accomplished) introduce new elements for free into pledges. We would like to hear from you (backers) what you would like to see as future stretch goals.

Specifications

  • Audio output : 8 channels
  • Audio input : 6 channels
  • Sample rate : 96 kHz
  • Resolution : 24 bit
  • Codec : CS42448 (manufacturer page)
  • Clocking : Chip oscillator driven for low jitter performance.
  • Extra Requirements : None, just plug onto your Pi.
  • Software Requirements : Will be part of the stock Raspbian distribution, with drivers uploaded to the official Raspberry Pi git tree. This is similar to the previous hardware we have released and the drivers ship with standard Raspbian ready and working. We also provide setup scripts on the support forum.
  • Support : The raspberry Pi forum, stackexchange and this Audio injector specific forum.

Specifications : balanced breakout

Add to the previous specifications the following :

  • 8 output and 6 input 1/4" balanced sockets.
  • 20 pin header for both input and output, which includes differential signals and power.
  • Mute pin for output header.
  • Using metallized film capacitors for optimum linear performance.
  • Professional audio line levels (around 1.5 V peak).
  • Threaded connectors with nuts for face plates (panels).
  • Output breakout dimensions : 190mm x 45mm
  • Input breakout dimensions : 145mm x 35mm

Previous kickstarter campaign

Previously the Audio injector was successfully released on Kickstarter. The Audio injector was delivered on time (one month after the end date of the campaign).

Back this project and save

From experience, Kickstarter allows you to pickup the product at a much reduced rate (our previous product was around 15% to 20% cheaper on kickstarter, mainly because of the Amazon and Ebay fees).

Risks and challenges

We have previously kickstarted and delivered a Pi sound card on time.

This is a reasonably low risk project because of the amount of prototyping and development we have put in pre launch.

We have also demonstrated our ability to prototype, manufacture, deliver and support successfully.

For those who pledge for the balanced breakout versions, we have given ourselves extra time to prepare the balanced breakouts. We will be seeking input from you as the campaign progresses on desires and needs for the balanced breakouts, so that we can make sure this product is as fully functioning as you would expect.

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Questions about this project? Check out the FAQ

Support this project

  1. Reward no longer available

    Pledge AU$ 51 or more About $37

    Audioinjector card (early bird, $39 USD)

    Early bird special (approx $38.60 USD)

    You will receive 1 Audio injector Octo surround sound card.

    Shipping is around $7 USD

    Less
    Estimated delivery
    Ships to Anywhere in the world
    Reward no longer available 20 backers
    AU$
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  2. Select this reward

    Pledge AU$ 57 or more About $42

    Audio injector card - RCA ($44 USD)

    Kickstarter special (approx $43.50 USD)

    You will receive 1 Audio injector Octo surround sound card. With RCA breakouts.

    Shipping is around $7 USD

    Less
    Estimated delivery
    Ships to Anywhere in the world
    82 backers
    AU$
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  3. Select this reward

    Pledge AU$ 112 or more About $82

    2x Audio injector cards - RCA ($84 USD)

    Kickstarter special (approx $83.50 USD)

    You will receive 2 Audio injector Octo surround sound cards. With RCA breakouts.

    Shipping is around $9 USD

    Less
    Estimated delivery
    Ships to Anywhere in the world
    13 backers
    AU$
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  4. Select this reward

    Pledge AU$ 138 or more About $101

    Audio injector hat - balanced ($100 USD)

    Kickstarter special (approx $99.50 USD)

    You will receive 1 Audio injector Octo surround sound card. With RCA breakouts and balanced powered breakouts. 1/4" (TRS) versions.

    Shipping is around $13 USD

    Less
    Estimated delivery
    Ships to Anywhere in the world
    21 backers
    AU$
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  5. Select this reward

    Pledge AU$ 160 or more About $117

    3x Audio injector cards - RCA ($120 USD)

    Kickstarter special (approx $120 USD)

    You will receive 3 Audio injector Octo surround sound cards. With RCA breakouts.

    Shipping is around $13USD

    Less
    Estimated delivery
    Ships to Anywhere in the world
    4 backers
    AU$
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  6. Select this reward

    Pledge AU$ 262 or more About $191

    2xAudio injector - balanced ($189 USD)

    Kickstarter special (approx $188.5 USD)

    You will receive 2 Audio injector Octo surround sound cards. With RCA breakouts and balanced powered breakouts. 1/4" (TRS) versions.

    Shipping is around $17.50 USD

    Less
    Estimated delivery
    Ships to Anywhere in the world
    7 backers
    AU$
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  7. Select this reward

    Pledge AU$ 393 or more About $287

    3xAudio injector - balanced ($283 USD)

    Kickstarter special (approx $283 USD)

    You will receive 3 Audio injector Octo surround sound cards. With RCA breakouts and balanced powered breakouts. 1/4" (TRS) versions.

    Shipping is around $26 USD

    Less
    Estimated delivery
    Ships to Anywhere in the world
    0 backers
    AU$
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Funding period

- (39 days)