Pro-Audio Concept

Dean posted Jun 10 '15, 14:55:

ok, so i've read about this project today on social media and i'm so glad someone has finally made this kind of device a reality.

A raspberry pi engine with SD card functionality always seemed like the most logical way of approaching this DIY method of building an audio device, however the one i've had in my head for a few years now is SLIGHTLY different to the sampler box, although it's arguably more straight forward.

Please, forgive me in advance as the only code i know how to writeis html/css and the only thing i've soldered is some LED strip and the insides of a few guitars... so i'm going to need some help, and some guidance if i'm going to finally make my idea a reality.

enough of the lifestory... my idea in brief;

"Backing Track Box"

  • 4 to 8 audio outputs
  • audio loaded on an SD card
  • play, forward, back and stop buttons

so... a band, or a singer, or any kind of performer who wants to use backing tracks but doesn't want to lug round their expensive brand new macbook with them and risk getting it stood on or crashing half way through the gig because the software update loads up!

the example; load your backing tracks onto the SD card, and either via software or some simple coding (like i've seen on this site) tell the click track to be output 1, the bass to be output 2 and so on, plug audio output 1 into your headphone amp, output 2 into the bass amp and so on... hit play and you're off.

cheap, inexpensive, simple, easy backing track box... NO manufacturer from Korg, Roland etc etc are making this machine. It's devastatingly simple in it's concept, and it's success will be in the fact that it's so cheap and easy to put together (for you experts ofcourse)

Does anyone else see the potential here? Imagine how many musicians and performers around the world would gladly ditch their expensive macbook based set up, with audio interface and a CPU intensive DAW just to run a couple of simple audio backing tracks.. in favour of a small, portable, simple and effective option instead?

like i said, i'm going to need help, but this idea i've had it for a few years now and only today have i uncovered the genius behind this samplerbox who's finally unlocked the potential of the R.Pi/SD card engine!

:) hope i didn't go on for too long and i didn't come across as too much of a newb.


joseph posted Jun 11 '15, 00:19:

Hi Dean,

Thanks for sharing this here! Yes I think it's a cool idea...
I want to say: start the project! (If I wasn't busy myself with SamplerBox + other projects I would help you!)
All you need is :

  1. have a Pi,
  2. some basics about Python (it's a really fun language and easy to learn),
  3. use PyAudio (a Python module for sound),
  4. find a way to have 8 outputs. That might be the difficult part! You need to find a digital-analog-converter (DAC) with 8 outputs... I suggest that you dig in forums, electronics chat, FabLabs, etc. to find this. Maybe have a look at Texas Instruments PCMxxxx components, or AnalogDevices DAC (maybe this one ? I haven't checked, it's just a random 8-channel DAC)... Oh a last thing: if you want 8 stereo outputs, you need 16 channels, that will probably be difficult, but not impossible.

If you spend 1 week of work for each of these steps, you'll have a prototype.

My advice would be: don't wait too much (people who have the skills to do it for you are probably busy with their own projects), and start! Work on a minimal prototype (maybe with only 2 outputs for a start) and then people will help you to improve! That will be a cool project!

Dean posted Jun 11 '15, 00:43:

thanks for the reply mate... encouraging words :)

quick few questions then;

  • is python the only language i'd need to get my head around?
  • is this language the best language to learn for R.Pi or is it the best language for this particular project?
  • the DAC side of things, i understand it's not as simple as just soldering 8 jack sockets onto a board, but how hard would it be to have it work with more common USB audio interfaces? for example, an M-audio or Focusrite multiple output device?
  • that link you kindly provided, are those just straight up pure DACs and nothing more?

obviously, the fundamental point here is just replacing the common personal computer or laptop with a scaled down simplified focused computer system, centred around the R.Pi...

i'd be happy with a prototype with just four working outputs at the beginning... my homework shall commence :)

joseph posted Jun 11 '15, 01:44:

Yes I really think Python will be enough to do this (+ basic Linux skills, but you probably already have, if you use a Raspberry Pi?)
I suggested Python, because a) it's a good language to learn, easy b) it's beautiful and very powerful (I used it for Samplerbox, and with good optimization, I had no performance problems) c) it's very "trendy" now, more and more people are using it each day.
Many people will say "trendiness" is a bad argument, but I really think there's a reason why there are more and more Python users. One reason amongst others: you have ready-to-use packages for nearly everything!

About using a USB audio interface, never tried myself to connect a 8 output audio interface to the Pi. I would be interested to know if/how it works when you'll have tried.

(The link that I provided was just one of the first google results of DAC 8 channels, so I know nearly nothing about it.)

Dean posted Jun 11 '15, 02:03:

trendy is cool and cool is trendy... i'm not scared of joining the coding hipsters :) thanks for the help mate, i'll let you know how i get on

Dean posted Jun 11 '15, 02:07:

actually... i have no idea about linux at all, other than it's the "third" operating system. and i'm a solid user of OS X -- am i gonna have problems?

joseph posted Jun 11 '15, 02:22:

Then you'll have a week for learning it (step #1 mentionned in my 00:19 post ;) ), so that you can achieve steps 1-2-3-4 in 4 weeks :)

John posted Sep 3 '18, 14:27:

Hi Dean

Just saw this post. Actually, this project has been brought to reality meanwhile. Check Basically, you can attach any linux-compatible audio interface by USB and play your backing tracks over this interface. It's open source and you're very welcome to become a contributor.


Gmeader posted Sep 14 '18, 02:27:

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