开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. BITX20
  2. Messages
Single Messages Topics Expanded Polls

Re: SBITX v3 - Ability to use a Headset for phone modes

Paul
 

A little progress made to solve a bit of a thorny issue regarding what happens when the sbitx is rebooted when a usb device is connected like a headset. Sorry bit of a long post, but it needs to be.
Not much point in connecting things up if a reboot changes the order of devices, this has involved a fair amount of learning and research but hopefully it has been worth it.
  • I know if I run the speaker-test -D default -c 1 -t wav command the sound comes out of the sbitx speaker
  • If I run the?speaker-test -D plughw:CARD=II,DEV=0 -c 1 -t wav command, the sound comes out of my USB headset
and then if I run the arecord -D "plughw:CARD=Loopback,DEV=1" -f cd | aplay -D "plughw:CARD=II,DEV=0" and then start the sbitx app, I get sound from the radio fed to both the speaker and my USB headset. The headset volume is a little on the low side but it is usable and is progress. Adding the -f cd option to the arecord command actually improves the audio quality fed to the headset by reducing some of the noise level on the audio from the radio.

I have now updated the /etc/rc.local file to create/amend the number of Loopback devices available:
modprobe snd-aloop enable=1,1,1,1 index=1,2,3,4

(If you are not interested in connecting other headset devices e.g. USB or Bluetooth, I would amend this line to read modprobe snd-aloop enable=1,1 index=1,2 to remove the unwanted Loopback_2 interface to keep things simple and tidy.)

Using this update creates 4 loopback interfaces so that when cat /proc/asound/cards is run you get a list of the available sound cards:

pi@sbitx:~ $ cat /proc/asound/cards
?0 [audioinjectorpi]: audioinjector-p - audioinjector-pi-soundcard
? ? ? ? ? ? ? ? ? ? ? audioinjector-pi-soundcard
?1 [Loopback? ? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 1
?2 [Loopback_1? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 2
?3 [Loopback_2? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 3
?4 [Loopback_3? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 4

We know that audioinjectorpi (card 0) is used for the sbitx audio I/O
We know that Loopback (card 1) is used for the output to digital software such as JTDX, FLDIGI etc.
We know that Loopback_1 (card 2) is used as the capture interface from the digital software such as JTDX, FLDIGI etc.
As delivered Loopback_2 (card 3) is not used for anything (that I can find anyway)
So to mirror the digital audio I/O I created an additional Loopback interface using the update to /etc/rc.local

Now for the device order problem: when I connected the USB headset after powering on the radio it would appear at the end of the list using cat /proc/asound/cards:
pi@sbitx:~ $ cat /proc/asound/cards
?0 [audioinjectorpi]: audioinjector-p - audioinjector-pi-soundcard
? ? ? ? ? ? ? ? ? ? ? audioinjector-pi-soundcard
?1 [Loopback? ? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 1
?2 [Loopback_1? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 2
?3 [Loopback_2? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 3
?4 [Loopback_3? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 4
?5 [II? ? ? ? ? ? ?]: USB-Audio - Jabra EVOLVE 30 II
? ? ? ? ? ? ? ? ? ? ? GN Audio A/S Jabra EVOLVE 30 II at usb-0000:01:00.0-1.1, full speed
pi@sbitx:~ $?

However if I rebooted the radio with the USB device still connected then the listing would look like?

pi@sbitx:~ $ pactl list cards short

54??????????????alsa_card.usb-GN_Audio_A_S_Jabra_EVOLVE_30_II_0000F358FA9E07-00????????????alsa

55??????????????alsa_card.platform-soc_sound??????????????????alsa

56??????????????alsa_card.platform-snd_aloop.2???????????????alsa

57??????????????alsa_card.platform-snd_aloop.1???????????????alsa

pi@sbitx:~ $

NOTE the different command used, still achieves the same thing and this was being used before I got to my solution. The issue here is that the USB device is now top of the ordered list and prevents sbitx from accessing the audioinjectorpi card because the USB device is now hw:0,0 instead of the audioinjector pi device. Note also that a Loopback interface has also disappeared!
if I unplug the USB device and reboot the correct order is resumed :

pi@sbitx:~ $ pactl list cards short

54????????????? alsa_card.platform-soc_sound????????????????? alsa

55????????????? alsa_card.platform-snd_aloop.2?????????????? alsa

56????????????? alsa_card.platform-snd_aloop.0?????????????? alsa

57????????????? alsa_card.platform-snd_aloop.1?????????????? alsa

pi@sbitx:~ $

Normal service is resumed now, If I connect the USB headset again it gets added to the list at the end as it should:

connect headset:

pi@sbitx:~ $ pactl list cards short

54????????????? alsa_card.platform-soc_sound????????????????? alsa

55????????????? alsa_card.platform-snd_aloop.2?????????????? alsa

56????????????? alsa_card.platform-snd_aloop.0?????????????? alsa

57????????????? alsa_card.platform-snd_aloop.1?????????????? alsa

106?????????? alsa_card.usb-GN_Audio_A_S_Jabra_EVOLVE_30_II_0000F358FA9E07-00??????????? alsa

pi@sbitx:~ $


Reboot again with the headset connected just to prove the point:

pi@sbitx:~ $ pactl list cards short

54????????????? alsa_card.usb-GN_Audio_A_S_Jabra_EVOLVE_30_II_0000F358FA9E07-00??????????? alsa

55????????????? alsa_card.platform-soc_sound????????????????? alsa

56????????????? alsa_card.platform-snd_aloop.2?????????????? alsa

57????????????? alsa_card.platform-snd_aloop.1?????????????? alsa

pi@sbitx:~ $


After headscratching, extensive use of Google and testing and retesting here is the solution:
In order to consistently achieve a correct order of devices a couple of commands were used to determine device names, note that I am totally focussed on using ALSA here to minimise complexity.
What we need to achieve is this order whenever the device is rebooted:
pi@sbitx:~ $ cat /proc/asound/modules
?0 (efault)
?1 snd_aloop
?2 snd_aloop
?3 snd_aloop
?4 snd_aloop
?5 snd_usb_audio
pi@sbitx:~ $?

or

pi@sbitx:~ $ cat /proc/asound/cards
?0 [audioinjectorpi]: audioinjector-p - audioinjector-pi-soundcard
? ? ? ? ? ? ? ? ? ? ? audioinjector-pi-soundcard
?1 [Loopback? ? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 1
?2 [Loopback_1? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 2
?3 [Loopback_2? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 3
?4 [Loopback_3? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 4
?5 [II? ? ? ? ? ? ?]: USB-Audio - Jabra EVOLVE 30 II
? ? ? ? ? ? ? ? ? ? ? GN Audio A/S Jabra EVOLVE 30 II at usb-0000:01:00.0-1.1, full speed
pi@sbitx:~ $

The solution is straightforward when you know how and what it is but it took a bit of finding along with trial and error :-)
Create this file (it doesn't exist on the delivered sbitx) using the command:
sudo nano /etc/modprobe.d/alsa-base.conf?

Add these lines to the file:
options (efault) index=-2? ? ? ? ? ? ? ? ? ? ? ? ? #am sure this should say default in the brackets but that is how the hw:0,0 device we want was listed in the cat /proc/asound/modules command
options snd_usb_audio index=5
?
Save the file and reboot with the USB device still connected. Note it is the output from the command cat /proc/asound/modules command that is important for this to identify the correct device names to use in the file. The higher the index value, the lower down the priority list they appear. to be really sure it might be worth adding the all the interface modules with an assigned index value to properly maintain the list order.

Do the check commands to ensure the USB device is at the bottom of the list (index=5) following reboots:
pi@sbitx:~ $ cat /proc/asound/cards
?0 [audioinjectorpi]: audioinjector-p - audioinjector-pi-soundcard
? ? ? ? ? ? ? ? ? ? ? audioinjector-pi-soundcard
?1 [Loopback? ? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 1
?2 [Loopback_1? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 2
?3 [Loopback_2? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 3
?4 [Loopback_3? ? ?]: Loopback - Loopback
? ? ? ? ? ? ? ? ? ? ? Loopback 4
?5 [II? ? ? ? ? ? ?]: USB-Audio - Jabra EVOLVE 30 II
? ? ? ? ? ? ? ? ? ? ? GN Audio A/S Jabra EVOLVE 30 II at usb-0000:01:00.0-1.1, full speed

pi@sbitx:~ $ cat /proc/asound/modules
?0 (efault)
?1 snd_aloop
?2 snd_aloop
?3 snd_aloop
?4 snd_aloop
?5 snd_usb_audio
pi@sbitx:~ $?
?
Now that bit is sorted we can start to try and reliably route audio to a USB headset based on the knowledge that the device whether plugged in or not won't affect the core audio routing of the sbitx radio.?
Just got to work that bit out now using the Loopback_2 for playback to the USB device and Loopback_3 for capture from the USB device microphone, that way we don't impact the digital functionality of the radio.
Might need some coding help with that bit, logically I know it can be done having proved some of the routing via the command line earlier, but now need the output from the codec that feeds the speaker and Loopback(card 1) to also feed Loopback_3(card 3) for play with a volume control (maybe using the Master Volume)? capability to drive the headset with more audio.?
Another option would be to take the output/input directly to/from the USB device but maybe that's a bit trickier

I believe an alternative headset solution is now a bit nearer

Regards
Paul G0KAO
Join [email protected] to automatically receive all group messages.