Octo out order issue

[pierlox]

Dears,

I'm quite a beginner on raspi and just purchased an octo card to work on a simple 8 out synth in Pure Data. Sorry if my explanations aren't very clear…

Because I will not use inputs on this project, I thought I might unplug the 6 inputs (to improve compacity). So, I did some tests with the input board plugged and unplugged, using a PD patch with 8 audio outputs (using the [dac~ 1 2 3 4 5 6 7 8] object) and I found some strange results (please see scheme attached) :

• Without the 6 inputs board :
— the order of outputs seems logical but the audio signals of 5 and 6 outputs are mixed on both outs (5 and 6)
— the out n°8 has a lower audio signal and some audible distorsion

• With the 6 inputs board plugged :
— order seem tricky : 3-4-5-6-7-8-1-2
— there is the same trouble with mix on 5 and 6 outputs (the physical ones) and low vol/disto on n°8 (now outputting signal of channel 2)

Am I doing anything wrong ?! Is that possible there is a physical mis-soldering on the 5 and 6 outs ? Any idea that might help me ?

Kind regards,
Pierlox

octo-outs.jpg (139.74 KiB) Viewed 2641 times

[tha-poke]

I was having major issues with pure data reordering outputs every time i restarted it or the pi, I sorted it by using jack and starting the jack server at boot, then loading pd with a separate script which connects pd to the Octo outputs.

Are you using alsa or jack? I couldn’t figure out how to sort this using just the alsa driver.

[pierlox]

Thanks Tha-Poke for your reply!
Yes I try to do it using only ALSA, but as you said Jack seems to be more than helpful. So I'll go this way.
But concerning the mix of 5-6 outs I guess it's more an hardware issue and Jack won't help.

[flatmax]

Hi there,
I haven't noticed mixing between channels 5 and 6 - interesting !

What is your software setup - PD I see. Can you tell me if PD opens both input and output at the same time ? Or does it open one then the other much later ?

Regarding channel 8, you may find this informative :
http://forum.audioinjector.net/viewtopic.php?f=9&t=3080

Matt