nRF5340 Audio DK. I want to set to Audio Demo to 3ch sink

[Pio_NSatou]

I have four of these devices. nRF5340 Audio DK.

I would like to use them as follows. Is there a way to set them up?

Device A: source

Device B: sink left

Device C: sink right

Device D: sink center

Each will be connected with CIS.

The audio to be streamed will be 3ch: left, right, and center.

I would like to see it in action as a simple demo, not as a product.

 

I think there are three issues.

1. The chip does not have the processing power to stream 3ch audio.

According to this QA, I understand that multi-channel is difficult due to the chip specs.

https://devzone.nordicsemi.com/f/nordic-q-a/92980/query---nrf5340-audio-dk---configuration-to-stream-multiple-stereo-audio?pifragment-684=1

For example, can this be cleared by lowering the audio quality or some other setting?

 

2.The source output cannot be set to output 3ch.

 

3.The sink set cannot be set to left, right, and center.

I have already confirmed that it can be operated as two sinks (left and right).

It seems that there are parameters like these, but I don't know which ones are valid.

https://developer.nordicsemi.com/nRF_Connect_SDK/doc-legacy/2.5.3/nrf/applications/nrf5340_audio/README.html#cmdoption-arg-CONFIG_BT_ASCS_ASE_SNK_COUNT

[Elfving]

Hello,

1. The chip does not have the processing power to stream 3ch audio.

First of all, you are somewhat right in this. If you want 3 different streams set up from one source that might be a bit much for nRF5340 to handle. There is a rule of thumb which states that nF5340 wuld spend about 30% of its computational power on one of these streams with 96 kbps. So if you would even do 2 of them, you need to make sure that you are not doing anything too intensive in addition to that. 3 however would easily be a bit much if you want anything on top of this. It is also rather common to want some further audio processing in addition to sending out the streams themselves, so this is important to keep in mind.

Its also true that one could theoretically decrease the quality from 96 kbps. You could also simply back the left and right streams into one stereo CIS stream, meaning that you essentially have two streams here. 

2.The source output cannot be set to output 3ch.

Yeah there is some limitation there as well which I believe depends on the controller used. Could you tell me where you found this?

3.The sink set cannot be set to left, right, and center.

Meaning all of them at the same time? I thought that should be possible.

Try adding a center one in addition to left and right. Have one stereo CIG for the left and right channels, and let the last mono one be your sink center.

For more on how to configure them for this, see here.

Regards,

Elfving