Ideas to make Jack detect a tablet's microphone connected via USB (and present in Pulseaudio)? [ SOLVED ]

[Nachei]

My laptop's internal mic broke, so I looked for a way to replace it with the mic of an old Android tablet, connected via USB (it's very convenient to have this microphone always at hand without having to assemble anything when you have an idea, etc). I found this project:

https://github.com/gdzx/audiosource

and got it working without problems with Pulseaudio: the tablet's microphone shows in Pavucontrol as a device called "Unix FIFO source /tmp/audiosource (Microphone)", I can choose it in audio-recorder, and it records flawlessly.

Now I'm trying to take the next step and see of making it work with Jack, so that I can use the microphone in a DAW.

I've tried connecting to Jack with Cadence, the Pulseaudio > Jack bridge is enabled, but Catia's patchbay does not show this mic as a connection.

Do you think of something I could try to make this mic visible to Jack? It surprised me how simple to configure was this Audiosource program, "it just worked", but I'm wondering if such simplicity maybe also means that it doesn't have the code necessary to "talk to" jackd, etc... Thank you for any suggestion...

[bluebell]

If you use PulseAudio JACK Sink then jack-clients should be able to record from Pulseaudio.

[Nachei]

If you use PulseAudio JACK Sink

I assume I use it, I'm on Ubuntu 22.04.3., which runs with Pulseaudio, and when I start Jack, a box "PulseAudio Jack Sink" appears in Catia (what I don't get is a box showing the tablet's mic). I'm thus assuming Jack Sink is enabled by default in this system. I have no problem with any other Jack program.

then jack-clients

This takes to my previous question. What is a jack client? Does jack-sink turn any audio program you use automatically into a "jack client", or each program (the tablet-to laptop converter Audiosource in my case) needs to have their own code that "talks" to Jack, and maybe Audiosource does not have it? To sum up again, Pulse sees and uses the tablet mic, but Jack does not (no box in Catia).

should

Yeah, we both agree on what should be happening. But the tab's mic does not appear in Catia or Carla, and there's no way to use it via Jack. That's the reason for this post, to ask for some ideas, if maybe there's some config change I could look into, or an alternative way of doing it... This comment doesn't really advance my situation, but thank you for at least confirming that this is weird...

[Impostor]

Yeah, we both agree on what should be happening. But the tab's mic does not appear in Catia or Carla, and there's no way to use it via Jack.

All of Pulseaudio's output will be routed through pulseaudio-jack-sink. No individual connections for pulseaudio apps will be available. In jack's connection manager you must simply route the output of pulseaudio-jack-sink into your DAW. That routes all of pulseaudio's sound into your DAW, indiscriminately (any muting/mixing of pulseaudio sources must be done with a pulseaudio mixer).

Much nicer would be to get the mic input recognized in Jack directly, but I've no clue how to do that. That would mean using two distinct audio devices, one for the usb-input, one for output.
https://jackaudio.org/faq/multiple_devices.html

[LAM]

This is what I use to "expose" a Mic or any other source from PA to JACK with its own Sink and Source:

Code: Select all

#!/bin/bash

### Find the default input device
#MICROPHONE='alsa_input.usb-SunplusIT_Inc_FHD_Camera_Microphone_01.00.00-02.analog-stereo'
MICROPHONE=$(pactl get-default-source)
### Create an empty array
mic_pa_devs=()
### Load PA JACK modules and save the index in an array
mic_pa_devs+=( $(pactl load-module module-jack-sink sink_name=mic_out client_name=MicOut channels=1 connect=no) )
mic_pa_devs+=( $(pactl load-module module-jack-source source_name=mic_in client_name=MicIn channels=2 connect=no) )
### Load PA JACK loopback module and save the index in an array
mic_pa_devs+=( $(pactl load-module module-loopback source=${MICROPHONE} sink=mic_out latency_msec=1) )

function remove-mic-modules() {
### Load the file in the array
readarray -t pa_devs < /tmp/pa_devs

### Remove every modules by index
for module in "${pa_devs[@]}"
do
	pactl unload-module $module
	# or do whatever with individual element of the array
done

### Remove the temp file
rm /tmp/pa_devs
exit 0
}

# Set a trap for SIGINT and SIGTERM signals
trap remove-mic-modules SIGTERM SIGINT SIGKILL

### Wait for a keypress to remove the modules
#read -n 1 -s -r -p "Press any key to remove devices"
#echo
while true
do
	sleep 1
done

Use CTRL+C to exit and remove the Mic sources and sink. I use this script in RaySession so it's one click away to start/stop it.

[Impostor]

This is what I use to "expose" a Mic or any other source from PA to JACK with its own Sink and Source:

Isn't using alsa_in/out (https://man.archlinux.org/man/alsa_out.1.en) a better option, cutting out the middle man pulseaudio?

@Nachei: zita-ajbridge is a package found in the Ubuntu repo, providing equivalent functionality, with the extra promise of "much better audio quality". Although maybe it doesn't work with usb plugin devices: "The alsa device should be a 'hw:' one, i.e. direct access to a soundcard and not an ALSA 'plug' device." (https://kokkinizita.linuxaudio.org/linu ... guide.html)

[LAM]

That depends on your case, using PulseAudio allows you to select that Mic when using PA applications, so it can work with both PA and JACK.

@Nachei is using https://github.com/gdzx/audiosource that sends audio via USB to Pulseaudio from another device. Not sure how your suggestion would work here.

[Impostor]

That depends on your case, using PulseAudio allows you to select that Mic when using PA applications, so it can work with both PA and JACK.

@Nachei is using https://github.com/gdzx/audiosource that sends audio via USB to Pulseaudio from another device. Not sure how your suggestion would work here.

I was just thinking that if Pulseaudio can get sound from this usb connection, then one should also be able to get sound from it with just alsa.

[erlkönig]

You could introduce a udev rule, that, when the mic is connected to usb, runs a little script that does all the connection stuff.

[bluebell]

If you use PulseAudio JACK Sink

I assume I use it, I'm on Ubuntu 22.04.3., which runs with Pulseaudio, and when I start Jack, a box "PulseAudio Jack Sink" appears in Catia (what I don't get is a box showing the tablet's mic). I'm thus assuming Jack Sink is enabled by default in this system. I have no problem with any other Jack program.

then jack-clients

This takes to my previous question. What is a jack client? Does jack-sink turn any audio program you use automatically into a "jack client", or each program (the tablet-to laptop converter Audiosource in my case) needs to have their own code that "talks" to Jack, and maybe Audiosource does not have it? To sum up again, Pulse sees and uses the tablet mic, but Jack does not (no box in Catia).

should

Yeah, we both agree on what should be happening. But the tab's mic does not appear in Catia or Carla, and there's no way to use it via Jack. That's the reason for this post, to ask for some ideas, if maybe there's some config change I could look into, or an alternative way of doing it... This comment doesn't really advance my situation, but thank you for at least confirming that this is weird...

With PulseAudio JACK Sink the whole Pulseaudio output goes there. So you won't find your mic there explicitely.

There are alternatives: You can make JACK see your mic with zalsa_in.

Code: Select all

jack_load zalsa_in -i "-d hw:USB"

Instead of USB use the name you see with

Code: Select all

arecord -l

[Nachei]

All of Pulseaudio's output will be routed through pulseaudio-jack-sink. No individual connections for pulseaudio apps will be available. In jack's connection manager you must simply route the output of pulseaudio-jack-sink into your DAW. That routes all of pulseaudio's sound into your DAW, indiscriminately (any muting/mixing of pulseaudio sources must be done with a pulseaudio mixer).

Thank you so much for this great and clear explanation... This is something I didn't know about Pulseaudio and I thought it was going to solve my problem. I tried, per your suggestion, connecting in Catia the output of pulseaudio-jack-sink to the inputs of my DAW (Reaper), then created a track and armed it to record.

What happens is that I get the computer sounds through that track (e.g. the music player that was on)... but not the tablet's mic (tapping on it does not make react the levels, like it does in Pavucontrol).

The part of getting the computer sound makes sense to me, out of what you say... What doesn't is that the tablet's mic is still absent...

Related to that, here are the input devices I'm getting in Pavucontrol:

https://drive.google.com/file/d/1nh7DXF ... drive_link

When I tap on the tablet's mic, the levels of "Unix FIFO Source /tmp/audiosource" move, but the levels on "Monitor of Jack Sink" do nothing (and neither do in Output devices > Jack Sink). Shouldn't those levels be moving too with the taps, given that the sink receives the tablet mic's output?

[Nachei]

@LAM

Thank you for the script, it looked promising, when I ran it it creates a Mic_Out box, but connecting it to the DAW does nothing, I don't know what is it connecting (I haven't managed to understand PA yet and I'm not really sure what the script does...)

I didn't know about RaySession either, I'll also check it out, it looks cool...

[Nachei]

@Impostor

Thank you for the suggestion of zita-ajbridge, although, out of what you yourself say and even quote about the USB devices, I don't think in this case it's even worth trying (or is it?) Good to know for the future that its sound quality is better, by now the sound quality I get with Audiosource is more than enough for the quick-crappy demos I intend to use it for...

[Nachei]

@erlkönig

Thank you for the idea, udev is something I've hardly used and I've always been curious to harness more its power... Perhaps your suggestion is more of the "stage 2" kind, "once you have it working, optimize it"... I'm still at stage 1 I'm afraid, trying to have something that works...

[Nachei]

@Bluebell

Thank you for this other great suggestion... Unfortunately, with arecord -l I only get

Code: Select all

**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC269VC Analog [ALC269VC Analog]
  Subdevices: 0/1
  Subdevice #0: subdevice #0

This doesn't seem to me like something USB connected, but rather my broken built-in laptop mic....

However, one of the many things I found in Internet and tried without understanding too much:

Code: Select all

pacmd list-sources | grep -e 'index:' -e device.string -e 'name:'

gives

Code: Select all

    index: 1
	name: <alsa_output.pci-0000_00_1f.3.analog-stereo.monitor>
		device.string = "0"
    index: 2
	name: <alsa_input.pci-0000_00_1f.3.analog-stereo>
		device.string = "front:0"
    index: 3
	name: <android>
		device.string = "/tmp/audiosource"
    index: 4
	name: <jack_out.monitor>
  * index: 5
	name: <jack_in>

Therefore the tablet gets detected by Pulseaudio (as index: 3, android)... but not as a hardware connection? Any idea why this might be? Hardware detection is another area where my knowledge is very patchy...

Thank you everybody for the great answers... Even if I don't finally get to solve this, Pulseaudio and Jack have stopped being the dark mystery they used to be for me...