2 interfaces, 2 jackd, couple them

[bluebell]

As I wrote Ihave 2 interfaces and need all of their outputs.

My first attempt with alsa_out on the 2nd interface worked but when it ran with 48000 then starting Audacity broke it.

So I am using another setup now:

jackd (on interface 1)
jackd -n monitor (on interface 2)

They can be coupled:

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jack-stdout -q -e float "Calf Studio Gear:Equalizer 12 Band Out #1" "Calf Studio Gear:Equalizer 12 Band Out #2" | JACK_DEFAULT_SERVER=monitor jack-stdin -q -e float system:playback_1 system:playback_2

Advantage: seems to be very stable
Disadvantage: additional latency on the signal that goes to the 2nd jackd

[bluebell]

I found zita-njbridge as well. Latency is much lower than using jack-stdout/in for coupling 2 jackd.

[khz]

• ALSA - MultipleCards >> http://alsa.opensrc.org/MultipleCards , "~/.asoundrc" >> https://www.alsa-project.org/main/index.php/Asoundrc#Virtual_multi_channel_devices
• Jack - multiple soundcards >> http://jackaudio.org/faq/multiple_devices.html
• JACK - alsa_in and alsa_out >> https://github.com/jackaudio/jackaudio.github.com/wiki/WalkThrough_User_AlsaInOut
• Zita-njbridge >> https://kokkinizita.linuxaudio.org/linuxaudio/
• Pulseaudio >> https://www.freedesktop.org/wiki/Software/PulseAudio/FAQ/#index31h3
• NetJackTrip >> https://linuxmusicians.com/viewtopic.php?p=95720#p95720
• audioadapter >> see below

I did it with the "audioadapter" (4.), all in one qjackctl (Jack2) instance:
The boot sequence of the (PCI/PCIe) sound cards is important so that the same prerequisite (sound card sequence) is always given when the computer is started.

1. Define first sound card. What's in the computer:

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cat /proc/asound/cards

edit:

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/etc/modprobe.d/alsa.conf

Example, take what "/proc/asound/cards" says!

- same drivers :

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    options snd-ymfpci index=0
    options snd-hda-intel index=1,2

- different drivers:

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    options snd-emu10k1 index=0
    options snd-via82xx index=1

2. Save settings in alsamixer (as root), make settings for each sound card separately and save them:

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alsactl store

3. Programs take certain soundkate:

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~/.asoundrc

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    defaults.ctl.card 0
    defaults.pcm.card 0
    defaults.timer.card 0

# https://wiki.linuxaudio.org/faq/start#qhow_to_order_the_numbering_of_soundcards_if_using_alsa_drivers


4. Merge multiple sound cards into qjackctl:

A)
Setup > Advanced: "Server Prefix" select "jackdmp", "H/W Monitor", "H/W Meter", "Soft Mode", (RT) "Priority (0 - 99)" (https://linux.die.net/man/1/jackd)
Setup >> Options >> [X] Run script at startup

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jack_load -i "-d hw:1 -i16 -o16" 9632 audioadapter && jack_bufsize 128 &

hw <-- you want to merge (sound card) (hw:1/hw:0/...)
-i <-- your number of sound card inputs
-o <-- your number of sound card outputs
9632 <-- as you want to call them (jackport name)
jack_bufsize <-- set the JACK buffer size
# https://github.com/jackaudio/jackaudio.github.com/wiki/WalkThrough_User_NetJack2

==>
Synchronisation your cards: with SPDIF, word clock or an internal sync port.
Is there anything about this in the manual of your used sound card?
(Personal, unverified and possibly false assumption: "? I think you need to synchronize the soundcards over one of the possibilities mentioned above. If it doesn't offer your sound card it won't work. The audioadapter does not do this. ?") IMHO

• https://en.wikipedia.org/wiki/Word_clock
  
• https://www.rme-audio.de/english/techinfo/sync.htm (German: https://www.rme-audio.de/techinfo/sync.htm); (https://www.rme-audio.de/download/hdspeaio_e.pdf)
• http://manual.ardour.org/synchronization/

B)
Alsa2jack (MIDI):
install:

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a2jmidid

Setup >> Options >> [X] Run script after startup

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sleep 5 && a2jmidid -e &

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sleep 5 && a2j -e &



Use 'a2j -e' instead of 'a2jmidid -e'.
The 1st option enables dbus.


https://linuxmusicians.com/viewtopic.php?p=74397#p74397
# sleep - delay a specified time period

Setup >> Settings >> Parameters >> MIDI Drivers [none]
Setup >> Miscellaneous >> [ ] ([none]) Provide support for ALSA sequencer

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>> http://jackaudio.org/faq/multiple_devices.html
I did it with the "audioadapter"

Interesting but I can't find the word "audioadapter" there. Where did you find docs about the audioadapter feature?

[khz]

No idea anymore. I was desperate and had searched the Internet for a solution. There were not much contributions/documentation and if then very different to it.
After several failed attempts of the different possibilities, the "audioadapter" worked. I documented it right away in the net because I and also other users maybe later want to have it easier.

1.) On the fast even that found: https://github.com/jackaudio/jackaudio.github.com/wiki/WalkThrough_User_NetJack2
2.) jack with multiple cards?: https://linuxmusicians.com/viewtopic.php?t=16062
3.) That's my original post: https://www.sequencer.de/synthesizer/threads/alsa-soundkartenreihenfolge.93441/page-3#post-1156186

[bluebell]

No idea anymore. I was desperate and had searched the Internet for a solution. There were not much contributions/documentation and if then very different to it.
After several failed attempts of the different possibilities, the "audioadapter" worked. I documented it right away in the net because I and also other users maybe later want to have it easier.

1.) On the fast even that found: https://github.com/jackaudio/jackaudio.github.com/wiki/WalkThrough_User_NetJack2
2.) jack with multiple cards?: https://linuxmusicians.com/viewtopic.php?t=16062
3.) That's my original post: https://www.sequencer.de/synthesizer/threads/alsa-soundkartenreihenfolge.93441/page-3#post-1156186

Very interesting. I'll play around with it.

The solution "coupling 2 jackd with zita-j2n and zita-n2j" has the disadvantage that zita-j2n crashes when I change the bufsize of the jackd where it's connected to. Else it would be nearly perfect (low latency).

[khz]

I'm not sure right now if the "audioadapter" command is important. "audioadapter" may be superfluous.
The "jack_load" command is important!

Once you have found the working setting, please document it comprehensibly for other users.
Good documentation is so helpful!

[bluebell]

I'm not sure right now if the "audioadapter" command is important. "audioadapter" may be superfluous.
The "jack_load" command is important!

Once you have found the working setting, please document it comprehensibly for other users.
Good documentation is so helpful!

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jack_load -i "-d hw:2 " onboard audioadapter

onboard: the name as seen in qjackctl, can be chosen freely
audioadapter: the resampling module, name has to be exactly like this

That does the job on one of my machines. Changing bufsize seems to work. This is the most promising attempt.

In a few days I can test it on the other machine with 2 usb-interfaces.

[bluebell]

The audioadapter internal client is the best solution for me. I can't believe that it is so badly documented, especially the internal clients audioadapter and netadapter.

Scarlett 2i4:
jackd -p512 -t2000 -dalsa -r48000 -p128 -n2 -Xseq -dhw:1

Add Scarlett 2i2:
jack_load -i "-dhw:2 -p64 -r48000" 2i2 audioadapter

[khz]

Now also included in the grandiose GNU/LINUX@AUDIO ~ /Wiki $ Howto.Info.


Wish/Request/: @qjackctl @Cadence/Cadence-JackSettings
Offer audio and net adapters under "Settings >> Parameters"?
Would make sense IMHO :freedom: and so