@whale-av It works!!!!! ahhh you save me today hahahaha... so stupid that I forgot to choose ASIO4All as input device... now I got sounds from all 8 channels 👍

@whale-av Thanks for the detailed explanation. I tried 4 devices as you said, but still there is only sound from [dac~ 1 2] but not other outputs from 3 to 8.

When using ASIO4all, I am not able to add multiple devices, and there is no sound at all.
Now I doubt whether the on-board sound interface supports 8-channel-output in Pure data or not 😂

@whale-av Hi David, Thanks for the reply. I tried that, but I may not route the speakers in a correct way. When I use multiple devices, how can I distinguish them with [dac~] object? Because there is only one option for the output device, which means I will choose the same four device for the audio output.

@weightless Hi, I set up 8 channels in audio settings.

Hi there,

I am using a MSI motherboard. There are four on-board audio output - Line out (main L/R), CS out (center/sub), SS out (side L/R), RS out (rear L/R). So it supports up to 8 channels.
I plugged four pairs of headphones, and test with system built-in audio test, and sound works fine. (The pic shows the system setting surround_sound_410.jpg )
When I set up in Pure data, I choose the right audio output with 8 channels, and test [dac~ 1 2 3 4 5 6 7 8]. Only the first two channels have sounds (it's from Line out, the main L/R). The other six channels do not have any sounds.

Do you have any idea why this happened? What else solutions I could give it a try?
The PD runs on Windows.

Now I'm using soundfiler (expr 44100 / sample size) to get the information of the playback speed. And I also use this to change the speed.

sound filer
|
expr 44100 / $f1
| (numberA)
|
phasor~

I wrote a patch about tap BPM calculator and I tapped with the soundtrack to get the BPM, and is there any connection between BPM and numberA (above)? or is there any possibility to change the playback speed by the BPM??

http://www.pdpatchrepo.info/hurleur/94C49BB8-8ECB-4C9F-A4DE-B4C9EC0D9D6D.png

Thanks guys, I'll try