Open Source DJ Mixer

I had an idea the other day for a Shruthi-style DJ mixer. What I mean by that is a hackable open source digital DJ mixer with A/D D/A converters on the inputs and outputs. There would be a variety of controls on the surface (faders and knobs) which you could freely assign to anything that you had going on in the firmware (EQs, deep frequency notches, fx etc.).

What do you guys think of this idea? What would the potential problems be? Hefty processor needed for all the DSP right?

How many inputs and outputs do you want?

Not sure, say four stereo ins and two stereo outs. Maybe a hardware switch for the inputs like a traditional mixer. What goes into a phono preamp I wonder?

Phono pre-amps have high gains and RIAA equalization. This is tricky to get right, but there are dozens of schematics for that on the net.

Simple EQs and FX on 4 audio channels is feasible with a microcontroller with DSP (STM32F4) but it’s starting to push the boundary a bit.

What is the advantage of a Open Source DJ mixer vs. one of the Behringer units? I realize that Behringer has a sort of tainted name to some, but they produce cheap versions of the big toys, in high volumes, with a often very good price-performance ratio.

Or just a simple midi controller, since it can do most of what you just said anyhow?

The advantage for me would be the ability to configure it how you wanted. You can set the EQ bands, you can decide what effects you want and how HQ you want them. Basically you get to decide how to spend the resources. Also it’s just a DIY project for it’s own sake as well as anything else.

Yeah a midi controller would do it but computers aren’t that robust or that compact, especially one with 8 inputs and four outputs.

Why has every piece of gear be digital? Whats the advantage having your EQs calculated by a CPU instead of using real analog ones?

See my my last post :stuck_out_tongue:

Say for instance you don’t want EQ, you want some sort of control of the dynamics instead. With this you could do have that.

Now that you mention 4 stereo channels and all this stuff, this is going to be a bit tough for a microcontroller-based project. Then it means DSP, then it means no open-source, because what’s the point of a project being open-source if you need to pay $$$$ for the development tools.

Well like I say the four stereo channels could be hardware switched from RIAA Phono to line so really it’s only 2 stereo. The point isn’t to have a lot, it’s to chose what you do have.

I want both as i got used to it :wink:

Sounds like you would be set with something like a raspberry pi and a midicontroller like the Reloop Disckjockey 2 Interface edition (out of production now, but the Reloop Jockey 3 should do the same).

This is one of those projects where just making something up for the sake of DIY is going to be really expensive, limited in usefulness, and sort of pointless due to other commercial(even cheaper) solutions, unless you know a ton about coding, hardware limits etc.

I guess if you would do it analog, modular with PlugIn Boards for the Gainstage/EQ/Compressor/FX for the single Channels and variable amounts of channels you are in the game…

Ehh, a behringer mixer would be cheaper…

A Pioneer mixer would probably be better for the price, and easier to sell for a good price…

I’ve used way too many crappy DJ mixers to ever be interested in a DIY one, well unless you’re going to clone a Bozak or something…

Maybe a DIY one that is built like a tank?

i would love to see a kit similar to the (french built) djr400.

I have no idea how complex it is under the hood.

i hate dj effects. just play the records.

Huh? 1650€? What am I missing?

point to point wiring? class a electronics?

djs pay more obviously. ridiculous price for sure.