Multi Channel Audio Output

#1

May sounds "crazy" but I'm wondering if would be possibile to use the audio inputs as audio outputs with a specific software update or if it would be possible to use phones as additional audio outputs such as 3 & 4.

#2

I don't think so...
Headphone out is hard wired to the main out and there are just two "audio quality" DACs
Also Ins are ins.
Maybe adding some hardware...

#3

Won't be possible to have the headphone act as extra output. 2 Mono channels or 1 Stereo is the only thing you can do.

#4

The audio adc/dac is stereo only, only has separate gain for line/headphones.

It's likely possible to do lo-fi stereo out with the 12bit DAC inside the microcontroller. Another option is encoding spdif output in firmware (but this will be a clock master, not able to slave to wordclock!). And it is also possible to add another audio converter. But all these options require a substantial development effort, not very high on my priority list.

#5

Thanks Johannes!
I was just dreaming about a 4ch out Axoloti :smile:

#6

what you might try is to use AM/FM synthesis to encode the signals inside the axoloti and send them all out the stereo bus. Then after this use a AM/FM demodulator+LP filter after the output to get out the seperate channels. Though you'll be loosing lots of higher frequencies in this process as this rather needs 96kbps or higher to work nice for frequencies up to 20khz..

#7

or you might divide the samplerate by two. Use one sample for one channel and the sample after it for the other and then keep switching back and forth. Then use an oscillator & demux & filter to seperate the channels again (this would be the AM version that gets you two more channels, though your highest possible frequencies will be 10khz)

#8

It'd be extremely hard to get near decent audio quality by multiplexing 2 audio channels through one audio dac channel, I'd not recommend.

#9

I didn't say it would sound good... but you'ld have your multiple channels..chiptune style... :wink:

#10

Would there be a possibility in the future to have multi-channel digital audio out through the USB port? I have an old 6-channel USB audio interface that is married to a control surface and would love to not only control the Axo but also use its audio interface. The box is an old Hercules DJ controller that spits out MIDI when you move sliders and controls on it and also has audio and MIDI ins and outs.

#11

btw, wouldn't it be possible to send multiple audio channels over the usb connection?
There are multiple audio interfaces doing this...so..

#12

Ohhh Yes please, that could be nice..

#13

though, probably it would need quite some cpu to do this, I gues?

#14

So Maybe just do the SPIlink to chain more axos together. Multiple outputs and more power.