lexicon omega: 2 channels instead of 4 ?

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spadan
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lexicon omega: 2 channels instead of 4 ?

Post by spadan »

Hello everyone,
I'm new here in LinuxMusicians.

After few years I am back with my old Lexicon Omega but I am in trouble with it on my Dell XPS laptop, Debian Buster.
I usually work on Ardour through QjackCtl.
The system recognize the device and it works. The problem is that I can't distinguish the 4 input channels; just 2.
I mean, connecting 2 microphones (Mic 1 and 2) and the piano-keyboard (line 1 and 2) I get everything coming in one stereo channel only.
Could you please help me in order to get it work correctly ?

Thank you very much for your attention !

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bluebell
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Re: lexicon omega: 2 channels instead of 4 ?

Post by bluebell »

How many inputs (capture_xx) does Qjackctl show (Connect -> system)?
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

spadan
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Re: lexicon omega: 2 channels instead of 4 ?

Post by spadan »

bluebell wrote:
Sun Apr 26, 2020 2:01 pm
How many inputs (capture_xx) does Qjackctl show (Connect -> system)?
Hi bluebell.

Just two, both for capture and playback.

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bluebell
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Re: lexicon omega: 2 channels instead of 4 ?

Post by bluebell »

You can set in Qjackctl (settings -> advanced) the number of the channels. Maybe that helps.
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

spadan
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Re: lexicon omega: 2 channels instead of 4 ?

Post by spadan »

I did it but the server "cannot be started"

Code: Select all

JACK server starting in realtime mode with priority 10
self-connect-mode is "Don't restrict self connect requests"
audio_reservation_init
Acquire audio card Audio1
creating alsa driver ... hw:Omega|hw:Omega|256|2|44100|4|2|nomon|swmeter|-|32bit
configuring for 44100Hz, period = 256 frames (5.8 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 24bit little-endian in 3bytes format
ALSA: cannot set channel count to 4 for capture
ALSA: cannot configure capture channel
Released audio card Audio1
audio_reservation_finish
Cannot initialize driver
JackServer::Open failed with -1
Failed to open server
11:17:00.059 JACK was stopped
11:17:02.164 Could not connect to JACK server as client. - Overall operation failed. - Unable to connect to server. Please check the messages window for more info.
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

musciencia
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Re: lexicon omega: 2 channels instead of 4 ?

Post by musciencia »

I have the same problem. But here is what I have found so far:

I have used Lexicon Omega with Ubuntu Studio for years without any problems until I upgraded to Ubuntu Studio 20.04.
After tryting diferent versions of Ubuntu Studio I notticed that the 2 channels instead of 4 issue started with kernel 4.15.0-101.

In other words:
On Ubuntu Studio 18.04.4 with kernel 4.15.0-20, Lexicon Omega works great. No problems at all.
On Ubuntu Studio 18.04.4 with kernel 4.15.0-101 (and later), Lexicon Omega can only capture 2 channels. Or at least I can only see 2 capture channels in qjackctl.

I'm still using Ubuntu Studio 18.04.4 with kernel 4.15.0-20, but it would be nice to be able to upgrade.

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nikgnomicradio
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Re: lexicon omega: 2 channels instead of 4 ?

Post by nikgnomicradio »

spadan wrote:
Mon Apr 27, 2020 9:19 am

Code: Select all

ALSA: cannot set channel count to 4 for capture
ALSA: cannot configure capture channel
if JACK cannot start with 4 capture channels, try starting with only 2 channels and add the other 2 later

This interface will probably have 2 subdevices in ALSA (see aplay -l)
each subdevice will be capable of 2 channels of audio capture

change JACK settings to:
  • Input Device: hw:Omega,0 channels: 2
  • Output Device: hw:Omega,0 channels: 2
(hw:Omega,0 is first subdevice, instead of hw:Omega for the whole device)

if JACK can be started with 2 capture channels, the additional 2 capture channels from the 2nd subdevice could be added with:

Code: Select all

/usr/bin/alsa_in -d hw:Pro,1 > /dev/null 2>&1 &
also suggest periods/buffer = 3 is usually optimal setting for a USB device

and try using Sample Rate = 48000Hz instead of 44100Hz - JACK always seems to run better at 48000Hz

spadan
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Re: lexicon omega: 2 channels instead of 4 ?

Post by spadan »

Thank you nikgnomicradio.

I have just tried the code you suggest:

Code: Select all

/usr/bin/alsa_in -d hw:Pro,1 > /dev/null 2>&1 &
without any error.

But starting up qjackctl it stops with this message:

Code: Select all

17:17:46.891 /usr/bin/jackd -dalsa -r44100 -p256 -n2 -D -Chw:Omega -Phw:Omega -i4 -o2
17:17:46.893 JACK was started with PID=9939.
no message buffer overruns
no message buffer overruns
no message buffer overruns
jackdmp 1.9.12
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2016 Grame.
Copyright 2016-2017 Filipe Coelho.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK server starting in realtime mode with priority 10
self-connect-mode is "Don't restrict self connect requests"
audio_reservation_init
Acquire audio card Audio1
creating alsa driver ... hw:Omega|hw:Omega|256|2|44100|4|2|nomon|swmeter|-|32bit
configuring for 44100Hz, period = 256 frames (5.8 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 24bit little-endian in 3bytes format
ALSA: cannot set channel count to 4 for capture
ALSA: cannot configure capture channel
Released audio card Audio1
audio_reservation_finish
Cannot initialize driver
JackServer::Open failed with -1
Failed to open server
17:17:46.978 JACK was stopped
17:17:49.056 Could not connect to JACK server as client. - Overall operation failed. - Unable to connect to server. Please check the messages window for more info.
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock

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