Multichannel audio playback (was: Multichannel audio listening)

[Rodolfo Medina <rodolfo.medina@gmail.com>]

Joel Roth <joelz@pobox.com> writes:

> On Mon, Mar 05, 2018 at 10:39:19AM +0100, Rodolfo Medina wrote:
>> Hi all.
>> 
>> After learning, some months ago, thanks to listers' help, how to live record
>> into a multi channel audio file, I was wondering about the reverse problem:
>> now I have my multi channel audio file, e.g. composed by three different
>> channels.  Is it possibile (I guess it is), and how?, to send each of the
>> three outputs into a different loud speaker and so listen to the song...?
>> 
>
> Hi Rodolfo,
>
> Ecasound is pretty convenient for routing audio.
>
> If you connect three powered speakers to the first three
> channels of a (sufficiently capable) soundcard and you're
> using ALSA (the default low-level linux audio API), it's
> pretty simple:
>
> For example,
>
> ecasound -i:3ch.wav -f:16,3,44100 -o:alsa,default


Four years ago this interesting thread.  Now I've purchased a Behringer
UMC404HD 4-channels audio interface and finally want to do my experiment.  Now
I have a 3-channel .wav file and 3 loudspeakers connected to Behringer's
output: I want to playback each channel to a different speaker.  I get error:

$ ecasound -i 3canali.wav -f:16,3,44100 -o alsahw,2,0
**************************************************************************
*        ecasound v2.9.1 (C) 1997-2014 Kai Vehmanen and others    
**************************************************************************
(eca-chainsetup) Chainsetup "untitled-chainsetup"
(eca-chainsetup) NOTE: Real-time configuration, but insufficient privileges
... to utilize real-time scheduling (SCHED_FIFO). With small buffersizes,
... this may cause audible glitches during processing.
(eca-chainsetup) "rt" buffering mode selected.
ERROR:  Connecting chainsetup failed: "Enabling chainsetup: AUDIOIO-WAVE:
... Only WAVE_FORMAT_PCM and WAVE_FORMAT_IEEE_FLOAT are supported."

Please help whoever can.

One more thing: on the back of Behringer there are two groups of `playback
outputs': group A and group B.  Each of the two groups has 4 holes: 2 black
6.35mm, one red RCA and one white RCA.  Please help also to understand how to
use them for my special purpose.  Besides, on Behringer's back there is one
more group of outputs called `Main Out' and including two 6.35mm and two XLR.

Thanks in advance for any help,

Rodolfo