Arduino based Digital Audio Headphone Matrix mixer

HI folks..i have planned to build a digital headphone matrix mixer( personal monitor for musicians)..

i had already completed the project in analog :

for reference..check it out
http://mickeydelp.com/news/106-passive-matrix-mixer.html

  • it takes 8 analog inputs connected via potentimeter (volume control) gives 8 different output i.e 8x8 matrix mixer

mix output of each channel is connected to an op amp LM786 in order to amplify the low signal to drive the headphones loud...

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i had succesfully completed the project..
but now i planned to do the same in digital..since i used 64 potentimeter.. :confused: :confused:

refernce model of the digital project:http://www.music-group.com/Categories/Behringer/Signal-Processors/In-Ear-Monitor-Systems/P16-M/p/P0421
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for this digital project:
first i have to convert all the analog signal into digital signal (ADC) and too simultaneously 8 channel at a sampling rate of 44khz and resolution of 16bit..(for goood quality).

i have planned to use this Simultneous ADC Chip with 8 analog input and 8 Digital Output:
http://www.ti.com/product/ADS1278

after the digital conversion of each channel i have to mix down the signals to each output..
i.e i have to mix all the signals and send to each output..therefore all each output all the 8 inputs ..(8 input -8 mixed output)

so the digital output from the adc holds all the 8 inputs.

we can take the headphone output either via digital using PWM or via analog DAC convertor

meanwhile ,i have to control the volume of the signals for each mixes..i planned to use a switch to select the channel and Rotatary encode potentiometer to control the volume .one for each mix.

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Can i able to completed this project ?? is it possible??
help me to finish up the project

thanks in advance!!!!

ads1278-ht.pdf (1.12 MB)

There's no way an Arduino will be able to read / output 8 channels of audio simultaneously.
What you could do, is using digital potentiometers, that are controlled by the Arduino. (Basically, the exact same thing you did before, but with digital pots instead of real ones.) You could then use 8 potentiometers to set the volumes for each channel, and 8 switches to select 1 of 8 channels.
Another approach would be to buy an 8 in / 8 out USB ADC/DAC audio interface (you can get a Behringer FCA1616 for €239) and connect it to a computer or a Raspberry Pi. You can then use software (e.g. a DAW) to set the volumes how you want them. And you could use the Arduino to build a MIDI controller to control the software with physical knobs. Keep in mind that this will add some latency, though.

Pieter

but now i planned to do the same in digital..since i used 64 potentiometer

There's a way to do almost the same thing with 16 (or 24) pots, and it can be done electronically or digitally, but not passively.

Of course you need 8 pots for the "regular" mix.

Then, you subtract each channel from the master mix. For example, channel-2 has gets a special master-mix with channel-2 subtracted. Then, you can mix channel-2 back in with a pot for level adjustment.

To do that with analog electronics each channel gets its own difference amplifier (made with an op-amp and almost as easy as a summing amplifier). ...I assume you know that analog mixers are built-around summing amplifiers. And each channel gets it's own summing amp to add it's own signal back in after adjustment.

You might want to give each user 2 "personal pots" so he/she can adjust "me" and "everybody else" separately (for a total of 24 pots).

And, you might want to build 8 little 2-input personal mixers for each user. If you do that, the main mixer doesn't need any additional pots/adjustments, it just needs 16 additional outputs... Each output has a "this channel" output (like an effect send on a regular mixer) and "everybody else" output.

DVDdoug:
Of course you need 8 pots for the "regular" mix.

Then, you subtract each channel from the master mix. For example, channel-2 has gets a special master-mix with channel-2 subtracted. Then, you can mix channel-2 back in with a pot for level adjustment.

The problem with one main mix is that some musicians need more control, for example, a bass player often asks to turn up the drums, and wants very little piano or voice.

Pieter