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Fixed: Connect Bluetooth Headphones with your Raspberry PI

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For a while I has been struggling in getting my Raspberry Pi connected to bluetooth headphones. This was with the idea to use in future projects available home assistants (like Google Assistant or Amazon Alexa) via bluetooth headphone or speaker on a Raspberry PI OS Lite installation (without the need of a GUI or graphical bluetooth manager).

My tests have been frustrated by common issues not well documented in the web and issues connecting an audio bluetooth device are really complex to find and solve. Also raspi-config can’t help, since this doesn’t include any bluetooth configuration in Interfacing options. So I started to follow many guides untill I reached a configuration that simply works. Main issues has been related to Bluetooth service errors on startup and connection breaking.

Solution came out with several fixes coming from different tutorials, being partcularly important the tricks from https://www.sigmdel.ca/michel/ha/rpi/bluetooth_n_buster_01_en.html and http://youness.net/raspberry-pi/bluetooth-headset-raspberry-pi. In this tutorial I’ll try to make all them together.

contemporary earphones and headphones on white table near smartphone


According to youness.net article, with the time there has been some changes in managing audio connection with Bluetooth. Raspberry PI OS uses BlueZ as Bluetooth stack:

  • BlueZ deals with pure Bluetooth tasks (pairing/connection/…)
  • So, BlueZ needs additional SW components for audio management
  • First Linux audio manager that comes to mind is ALSA
  • But, BlueZ (>= v5.0) doesn’t support ALSA anymore
  • Instead, BlueZ is now using PulseAudio (>= 5.0)
  • And, PulseAudio still uses ALSA

So, the chain changes should be the following:

Before: BlueZ → ALSA

Now: BlueZ → PulseAudio → ALSA

The following tutorial will help you to correctly connect bluetooth headphones with your Raspberry PI (not only model B devices, but any RPI model with onboard bluetooth module).

What We Need

Raspberry PI 4 model B image

I suggest adding to your shopping chart all needed hardware, so that at the end you will be able to evaluate overall costs and decide if continuing with the project or removing them from shopping chart. So, hardware will be only:

Check hardware prices with following links:

Amazon raspberry pi boards box
Amazon raspberry pi Zero W box
Amazon Micro SD box
Amazon bluetooth headphones box

Step-By-Step Guide

Install OS

We’ll start from standard Raspberry PI OS Lite installation with WiFi and ssh enables. So every command within the following paragraphs will be issued via ssh remote connection.

Be sure to have your OS up to date:

sudo apt-get update
sudo apt-get upgrade

Adding Pi To Bluetooth Users

This fix helps to use audio files from default pi user, without having to elevate privileges for each bluetooth action. Simply use the following command to add pi user to bluetooth group:

sudo usermod -G bluetooth -a pi

Now logout/login or reboot to have this change running:

sudo reboot now

Install Bluealsa and Pulseaudio Module

This module will be useful later to interface

sudo apt-get install bluealsa pulseaudio

SAP Driver Initialization Failure

The first issue comes from SAP (SIM Access Profile) driver initialization. If you check bluetooth service starting status:

sudo systemctl status bluetooth.service

you should find the following:

● bluetooth.service - Bluetooth service
Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2020-01-06 21:15:56 GMT; 2min 57s ago
Docs: man:bluetoothd(8)
Main PID: 424 (bluetoothd)
Status: "Running"
Tasks: 1 (limit: 2200)
Memory: 2.7M
CGroup: /system.slice/bluetooth.service
└─424 /usr/lib/bluetooth/bluetoothd

Jan 06 21:15:56 raspberrypi systemd[1]: Starting Bluetooth service...
Jan 06 21:15:56 raspberrypi bluetoothd[424]: Bluetooth daemon 5.50
Jan 06 21:15:56 raspberrypi systemd[1]: Started Bluetooth service.
Jan 06 21:15:57 raspberrypi bluetoothd[424]: Starting SDP server
Jan 06 21:15:57 raspberrypi bluetoothd[424]: Bluetooth management interface 1.14 initialized
Jan 06 21:15:57 raspberrypi bluetoothd[424]: Sap driver initialization failed.
Jan 06 21:15:57 raspberrypi bluetoothd[424]: sap-server: Operation not permitted (1)
Jan 06 21:15:57 raspberrypi bluetoothd[424]: Failed to set privacy: Rejected (0x0b)

The “Sap driver initialization failed.” notices that someting is going wrong on startup. This can be fixed simply stopping the SIM profile loading. With your favourite text editor (mine one is nano), modify “/lib/systemd/system/bluetooth.service” file to add “–noplugin=sap” option near “ExecStart=/usr/lib/bluetooth/bluetoothd” configuration:

sudo nano /lib/systemd/system/bluetooth.service

and make sure that your appear like the following (just adding –noplugin=sap as mentioned above):

[Unit]
Description=Bluetooth service
Documentation=man:bluetoothd(8)
ConditionPathIsDirectory=/sys/class/bluetooth

[Service]
Type=dbus
BusName=org.bluez
ExecStart=/usr/lib/bluetooth/bluetoothd --noplugin=sap
NotifyAccess=main
#WatchdogSec=10
#Restart=on-failure
CapabilityBoundingSet=CAP_NET_ADMIN CAP_NET_BIND_SERVICE
LimitNPROC=1
ProtectHome=true
ProtectSystem=full

[Install]
WantedBy=bluetooth.target
Alias=dbus-org.bluez.service

Now reboot

sudo reboot now

Privacy Setting Rejected Failure

Once rebooted, a new check on bluetooth service status shows that the third error is still occurring. Command:

sudo systemctl status bluetooth.service

should give you:

● bluetooth.service - Bluetooth service
Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2020-01-06 21:38:05 GMT; 3min 9s ago
Docs: man:bluetoothd(8)
Main PID: 424 (bluetoothd)
Status: "Running"
Tasks: 1 (limit: 2200)
Memory: 2.7M
CGroup: /system.slice/bluetooth.service
└─424 /usr/lib/bluetooth/bluetoothd --noplugin=sap

Jan 06 21:38:04 raspberrypi systemd[1]: Starting Bluetooth service...
Jan 06 21:38:05 raspberrypi bluetoothd[424]: Bluetooth daemon 5.50
Jan 06 21:38:05 raspberrypi systemd[1]: Started Bluetooth service.
Jan 06 21:38:05 raspberrypi bluetoothd[424]: Starting SDP server
Jan 06 21:38:05 raspberrypi bluetoothd[424]: Excluding (cli) sap
Jan 06 21:38:05 raspberrypi bluetoothd[424]: Bluetooth management interface 1.14 initialized
Jan 06 21:38:05 raspberrypi bluetoothd[424]: Endpoint registered: sender=:1.6 path=/org/bluez/hci0/A2DP/SBC/Source/1
Jan 06 21:38:05 raspberrypi bluetoothd[424]: Endpoint registered: sender=:1.6 path=/org/bluez/hci0/A2DP/SBC/Source/2
Jan 06 21:38:05 raspberrypi bluetoothd[424]: Failed to set privacy: Rejected (0x0b)

A simple restart of bluetooth service solves this problem, but solution is only temporary untill a new reboot comes. The solution for this is editing “/lib/systemd/system/bthelper@.service” file to add the “ExecStartPre=/bin/sleep 2” configuration. For this solution credits go to Ben Windsow on https://github.com/RPi-Distro/pi-bluetooth/issues/8#issuecomment-480270680. So open the above file:

sudo nano /lib/systemd/system/bthelper@.service

and make it the same as the following:

[Unit]
Description=Raspberry Pi bluetooth helper
Requires=bluetooth.service
After=bluetooth.service

[Service]
Type=simple
ExecStartPre=/bin/sleep 2
ExecStart=/usr/bin/bthelper %I

Reboot again and now everything should be ok with sudo systemctl status bluetooth.service.

Check That Pulseaudio Is Running

Next step and one of most common issues is that, when attempting bluetooth connection, Pulseaudio is not running. So, before proceding to bluetooth pairing, please check that it is running.

Type, from terminal window, the following command:

ps aux | grep pulseaudio

If this command returns the following output:

pi@raspberrypi:~ $ ps aux | grep pulseaudio
pi 538 0.0 0.0 7348 504 pts/0 S+ 22:01 0:00 grep --color=auto pulseaudio

then you must manually launch pulseaudio:

pulseaudio --start

so that you should see the correct status from ps aux | grep pulseaudio command:

pi@raspberrypi:~ $ ps aux | grep pulseaudio
pi 544 4.3 1.8 181592 17720 ? Sl 22:02 0:00 pulseaudio --start
pi 564 0.0 0.0 7348 488 pts/0 S+ 22:02 0:00 grep --color=auto pulseaudio

Pair Bluetooth Device

Finally, we can try that everything really works. Let’s configure bluetooth (note that I don’t use sudo because pi has been added to bluetooth group). First of all, consider that my headphones address is 00:25:DB:78:86:98, but in your case will depend on your hardware.

Set in pairing mode your bluetooth headphones according to their user guide. Go to the terminal.

Command:

bluetoothctl

Expected output:

pi@raspberrypi:~ $ bluetoothctl
Agent registered
[bluetooth]#

Command:

power on

Expected output:

[bluetooth]# power on
Changing power on succeeded

Command:

agent on

Expected output:

[bluetooth]# agent on
Agent is already registered

Command:

default-agent

Expected output:

[bluetooth]# default-agent
Default agent request successful

Command:

scan on

Expected output:

[bluetooth]# scan on
Discovery started
[CHG] Controller B8:27:EB:23:73:DF Discovering: yes
[NEW] Device 00:25:DB:78:86:98 BTC7

First row is RPI on board Controller. My headphones are these listed in second row.

Command (remember to change my Headphones addres with your one  from following command to the end!!!):

pair 00:25:DB:78:86:98

Expected output:

[bluetooth]# pair 00:25:DB:78:86:98
Attempting to pair with 00:25:DB:78:86:98
[CHG] Device 00:25:DB:78:86:98 Connected: yes
[CHG] Device 00:25:DB:78:86:98 UUIDs: 00001108-0000-1000-8000-00805f9b34fb
[CHG] Device 00:25:DB:78:86:98 UUIDs: 0000111e-0000-1000-8000-00805f9b34fb
[CHG] Device 00:25:DB:78:86:98 ServicesResolved: yes
[CHG] Device 00:25:DB:78:86:98 Paired: yes
Pairing successful
[CHG] Device 00:25:DB:78:86:98 ServicesResolved: no
[CHG] Device 00:25:DB:78:86:98 Connected: no

Command:

trust 00:25:DB:78:86:98

Expected output:

[bluetooth]# trust 00:25:DB:78:86:98
[CHG] Device 00:25:DB:78:86:98 Trusted: yes
Changing 00:25:DB:78:86:98 trust succeeded

Command:

connect 00:25:DB:78:86:98

Expected output:

[bluetooth]# connect 00:25:DB:78:86:98
Attempting to connect to 00:25:DB:78:86:98
[CHG] Device 00:25:DB:78:86:98 Connected: yes
Connection successful
[CHG] Device 00:25:DB:78:86:98 ServicesResolved: yes

Now you Bluetooth connection with your headphones is ready!

You will need to connect your bluetooth device at each connection. Otherwise, add following line in your /etc/rc.local file, before final “exit 0” row:

bluetoothctl connect 00:25:DB:78:86:98

(and, of course, bluetooth device will need to be powered on before Raspberry PI boot).

Test Your Headphones

From terminal, play audio example files (remember to use your headphones or bluetooth speakers address instead of mine!):

aplay -D bluealsa:DEV=00:25:DB:78:86:98,PROFILE=sco /usr/share/sounds/alsa/Front_Center.wav

You can also record your own test:

arecord -D bluealsa:DEV=00:25:DB:78:86:98,PROFILE=sco test.wav

and listen it

aplay -D bluealsa:DEV=00:25:DB:78:86:98,PROFILE=sco test.wav

to check both audio transmission and reception.

Now you should be able to correctly connect your bluetooth headphones / bluetooth speakers with your Raspberry PI.

Final step is using a common player to listen files like .mp3. This will require to create a default bluealsa profile and to specify in your player command options what output device it should use.

The default bluealsa profile can be arranged creating an .asoundrc file in pi default folder:

nano .asoundrc

In this file, use following lines (changing bluetooth address with your one):

defaults.bluealsa.interface "hci0"
defaults.bluealsa.device "00:25:DB:78:86:98"
defaults.bluealsa.profile "sco"
defaults.bluealsa.delay 10000

Save and exit. If you want to use omxplayer, which you can install with following command:

sudo apt install omxplayer

You will need the following simple command:

omxplayer -o alsa:bluealsa file_example_MP3.mp3

Enjoy!

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45 comments

  1. don’t think you need pulseaudio here
    bluealsa is able to connect without pulse.
    Also both working together is not recommended

    1. This solution worked for me for the 27 May 2020 RasPiOS build that was not working. THANK YOU for this solution!

    1. Hi Douglas.
      Bluetooth is really hard to work in Raspbian Lite and results can change from device to device. I’m going to write you to try more help in troubleshooting.

    2. I have never been able to get sound out of 2 different RPi 3s via BT now and have tried everything I can find online for the last two years now.

      I am beginning to disbelieve it works for anybody.

      Multiple different speakers always pair, and then connect, and are able to be seen from the pi but no sound ever comes out of the speakers.

      There must be another mixer setting, or switch to enable BT output.

      ….Larry

      1. Hi Larry,
        thank you for your feedback. With my CellularLine bluetooth headset I also had to work hard to make it working. Some keys which gave me results:
        – check pulseaudio is working: even if installed, pulseaudio could be not running. Once started, verify that its process is alive
        – bluetooth pairing seems to be working easily in Rasbpian Lite. But check – when you connect a device – that it remains connected
        – aplay worked to me with sco profile and a wav file previously recorded with same library and “arecord” command. so try this way first. If your device is an “output only” one, try downloading a wav file or let me know to generate one and make it available to you in my download area

        A different solution is listed in Gus comment. You can also try this one.

        If you have still problems, feel free to mail me (my contacts are in my Info page)

        1. Thanks for your reply.

          I did some noise out of the speaker using the PROFILE=A2DP in the aplay command line. The .wav file sounded like it was playing at about 1/10 speed, and the .mp3 file did output some random noise. This indicates most things are working, so far.

          Every other attempt no sound will come out of the speaker. Today I have rechecked pulseaudio is running but still no sound. Using A2DP or SCO I get silence until after about 45 seconds I get aplay kicking back with
          aplay: main:828: audio open error: no such device
          The speaker still hasn’t reported “disconnecting Bluetooth” at that point so the connection is still valid from the speaker’s point of view. Pulseaudio is still showing running in the ps list.

          This is the same results I got many times with the Alexa speaker also. They pair, connect and everything seems OK but will never produce sound.
          I wrote some pythin3 code to open a socket via BT and the speaker reports paired, and connected. Same thing with it. After trying many methods with Alexa and GH “right out of the book”, I assumed those brands would not allow other brands to interoperate with them.

          This tiny speaker I am using now connects and plays music from my Samsung S7, and my laptop, just fine. Something is missing on these RPi methods yet. Maybe I need to connect up a monitor and KB for a RPi desktop trial to prove it isn’t just a Raspbian command line thing
          **SIGH**

          1. If you are receiving some sound (even if a simple noise), this is a good signal: this means that bluetooth is paired and connected. This also could mean that in this moment you could have a simple coding problem. So, your next test it the one you are going to do: try with a deskop version able to let you have also more advanced music applications (like the famous vlc player) which are more likely to have a complete library for media decoding.
            Another trik: in terminal, you should be able to use “alsamixer” command, which enables a terminal console to manage volume for your audio devices.

          2. Thanks. The alsamixer only shows analogue devices, namely just one.
            The noise indicates the volume is loud enough. I’ll have to make a bench setup to get a monitor and kb on this Rpi. I would even be happy just to use a simple earphone jack speaker for this application but having trouble finding one of them too. They have incorporated video into the same jack making it non-standard.

      1. Hi kendun,
        undo-ing it is simple:
        – sudo nano /lib/systemd/system/bthelper@.service
        -> remove “ExecStartPre=/bin/sleep 2″ row
        – sudo nano /lib/systemd/system/bluetooth.service
        -> remove ” –noplugin=sap” option
        – sudo apt-get purge bluealsa pulseaudio

        Just for curiosity, are you getting errors or simply you can’t get sound?

  2. Awesome post thank you. I followed it and I have a few suggestions for improvements after having tried (and retried on a brand new SD card) the steps myself:

    1- I started with a fresh Pi Zero W, with a brand new Raspbian Lite (buster) installation
    2- I didn’t have to install PulseAudio. BlueAlsa alone worked. I skipped the section “Check That Pulseaudio Is Running” altogether
    3- For convenience, I created a file .asoundrc in my home directory for convenience, it included a profile called “bluealsa” that I referred to from the media players command line (see below)

    # Bluetooth headset
    defaults.bluealsa {
    interface “hci0” # host Bluetooth adapter
    # device “AA:00:A7:00:B8:D4” Vidonn – doesnt support A2DP! Commenting out
    device “D0:8A:55:08:FC:BE”
    profile “a2dp”
    }

    4- I learned that “SCO” and “A2DP” refer to the possible ‘services’ that your bluetooth audio device supports. If you have a speaker or high end headphones, they likely support A2DP . If they’re simple telephone headsets (like my Vidonn bone conduction headphones) they do not support A2DP but rather SCO (which is optimized for VOIP calls). They’re called “profiles”, replace SCO with A2DP where necessary.
    5- aplay expects a wav file, not an mp3 file 🙂 I jumped from my seat when aplay started playing the encoded data found in the mp3 file into my headphones (it was all noise)
    6- for omxplayer to be able to play over bluetooth you need to call it like the following (I wanted omxplayer because I needed to play video, not just audio). “bluealsa’ here refers to the name of the profile created inside the ~/.asoundrc file like I described above: omxplayer -o alsa:bluealsa

    1. Hi!
      Thanks so much for this post. It really saved me.
      SCO works for my buetooth speaker
      and a2dp for my headphones!

      Cheers.*

    2. I setup the .asoundrc as you suggested and that works fine for omxplayer. Any thoughts on how to get SoX to use the bluetooth output?

  3. Thanks. I followed your instructions, then my Jabra BT2080 works fine on my pi3 B+.
    I skipped chapter “Check That Pulseaudio Is Running”. Pulseaudio is not necessary here.

  4. pi@raspberrypi:~ $ sudo systemctl status bluetooth.service
    ● bluetooth.service – Bluetooth service
    Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset
    Active: active (running) since Sun 2020-06-28 11:36:45 EDT; 2min 34s ago
    Docs: man:bluetoothd(8)
    Main PID: 607 (bluetoothd)
    Status: “Running”
    Tasks: 1 (limit: 4915)
    Memory: 2.1M
    CGroup: /system.slice/bluetooth.service
    └─607 /usr/lib/bluetooth/bluetoothd –noplugin=sap

    Jun 28 11:36:45 raspberrypi bluetoothd[607]: Bluetooth daemon 5.50
    Jun 28 11:36:45 raspberrypi systemd[1]: Started Bluetooth service.
    Jun 28 11:36:45 raspberrypi bluetoothd[607]: Starting SDP server
    Jun 28 11:36:45 raspberrypi bluetoothd[607]: Excluding (cli) sap
    Jun 28 11:36:45 raspberrypi bluetoothd[607]: Bluetooth management interface 1.14
    Jun 28 11:36:45 raspberrypi bluetoothd[607]: Endpoint registered: sender=:1.24 p
    Jun 28 11:36:45 raspberrypi bluetoothd[607]: Endpoint registered: sender=:1.24 p
    Jun 28 11:37:03 raspberrypi bluetoothd[607]: Endpoint registered: sender=:1.45 p
    Jun 28 11:37:03 raspberrypi bluetoothd[607]: Endpoint registered: sender=:1.45 p
    Jun 28 11:37:03 raspberrypi bluetoothd[607]: RFCOMM server failed for Headset Vo

    ##########################
    RFCOMM server failed for Headset Vo
    ##########################

    Everything went smooth until very last step, then I got the error mentioned above.
    Any ideas about this issue?

    1. Hi joseph. Your error seems to be truncated. Please check with journalctl -xe for complete error label

  5. Hello! Thanks for the article. I have been following youness’s article but still not successful.
    So my main question is DOES THIS WORK WITH HFP PROFILE HEADPHONES? Because all the Pulseaudio related articles talk about using ofono with hfp profiles, which is proving to be another headache. Please let me know if it works.
    Thanks

    1. Hi Ebrahim. I’ll try to test it as soon as possible. Bluetooth world has a number of different hardware and profiles so huge that procedures working with some hardware could have issue with different hardware.
      In the meanwhile, you could try with a Raspberry PI OS Desktop installation, so having other packages that could visually help you.

  6. So I went all the way through the tutorial and got to the end, ran the tests and the audio came through and the recording worked. However, I cannot use it for anything else (browser, app ect.) Is this expected or did I do something weird?

    1. Hi,
      I just added a final section explaining how to use a common player (like omxplayer). What is important (and changes from app to app) is that you need to tell your software which output audio device use, pointing to bluealsa. In omxplayer it can be done with “-o” option. also defining tha .asoundrc file simplify bluealsa usage because it point by default to correct configuration.

  7. Hi All,

    For me bluetooth devices, either headsets or speakers were connecting successfully on various distros like ubuntu, raspbian or mate. However what I couldn’t achieve till date is utilizing the microphone of those bluetooth headsets. The headset was always connected for sound output. Though the bluetooth device shows in volume control gui, however I can’t record any voice through it. Getting frustrated now as I referred multiple solutions and all failed. Any help would be highly appreciated. This is the only thing which is pending in my issue list for raspberry pi which I have prepared for my day to day task which is online web-browsing and classes. And finding resolution would reduce the need of cable management and system can be set with fixed output and input from bluetooth headset.

  8. HI,
    Thanks for quick response. However, while looking at other solutions available online, I messed up with bluetooth config files and is now not able to connect with my handsfree. Would do a fresh install again and would update with results of your input.

  9. I’ve gone thorugh and completed the entire tutorial and have success with the test wav file, though when i try to use chromium or other programs the sound will default out te HDMI rather than go to the headphones. I dont want to disable HDMI sound as this is what i normally use, i would just like it to be able to switch for youtube videos. the sound is execllent through a2dp in the test.

  10. How to make these profiles appear on alsa-mixer and pactl list cards? They do not appear by default, and show only the HDMI and aux profiles

  11. Great tutorial, Thanks! It worked out of the box on my RPi 3B+ with Buster 10.7 and retropie 4.7.2.
    With one exception: with A2DP, sound is stuttering horribly. SCO works but sounds like I have a tin can speaker 😉 Disabling WiFi didn’t help. Any ideas how I could solve this?

    As for retropie: I cannot seem to find how to configure the ‘alsa:bluealsa’ PCM device in EmulationStation/RetroArch. Is that because this is a virtual driver? Suggestions, anyone?

    BTW retropie audiosettings destroys ~/.asoundrc. Oops. Somehow, installing bluealsa & pulseaudio caused all sound output to go to the jack, not to my previously configured HDMI. In trying to correct that, my bluealsa settings where overwritten. Fixed that, but still no HDMI audio.

    So, that’s three questions in one. Biggest thing is the stuttering A2DP. Any suggestions would be greatly appreciated!

    Note: I did not need to run ‘pulseaudio –start’ as more commenters suggested. I was already wondering why you didn’t include a ‘run-at-boot’ script for that 😉

    Versions:
    pulseaudio 12.2-4+deb10u1+rpi2
    bluealsa 0.13
    bluez 5.50-1.2~deb10u1+rpt2 (as installed by retropie)

  12. Just to let y’all know: I fixed 2 of the 3 problems. A2DP still stutters really bad; no progress there. I found no hints when searching for it on the web. My guess is a buffer size needs to be increased, but which & how?

    As for bluealsa, the following will enable BT output in RetroArch: add to, e.g., /opt/retropie/configs/all/retroarch.cfg a line
    audio_device = “bluealsa:DEV=11:AA:BB:CC:DD:EE,PROFILE=sco”
    with your own MAC. Unfortunately, this requires hardcoding your BT headset id..

    I did not succeed in getting BT output to work in non-retroarch emulators like openmsx, scummvm & dosbox. As ‘sco’ (16kHz mono) does not provide a very pleasant gaming experience, I didn’t investigate further, but any suggestions would still be appreciated nevertheless!

    I solved my HDMI vs. headphones output with a simple ‘sudo raspi-config’ > System Options > Audio > choose HDMI or headphones. This in turn edited ~/.config/pulse/-default-sink with the value ‘alsa_output.platform-bcm2835_audio.digital-stereo’ (when choosing HDMI).

    1. Hi Cayce. Thank you for your feedback.
      Regarding stuttering, I’ve discovered that some Raspberry PI users (expacially for PI3 B+) noted same problem when using togeher both bluetooth and WiFi. This is related to not perfect broadcom/cypress boards integration. Somu users on GitHub referred a solution from Cypress with following steps:

      1) Locate your “NVRAM” text file – it’s in /lib/firmware/brcm/brcmfmac-sdio.txt, where is 43430 or 43455 respectively. Make a backup copy somewhere safe to make it easier to undo the changes (or recover from an error).
      2) Open the file in a text editor, scroll down to the bottom (purely for neatness – these settings could probably go anywhere) and append the following:
      # Experimental Bluetooth coexistence parameters from Cypress
      btc_mode=1
      btc_params8=0x4e20
      btc_params1=0x7530
      3) Reboot.

      If not, I whould try to test with cable connection instead of WiFi. Please also be sure that your power supply is enought capable (I always suggest a PS able to dry at least 2,5/3 A).
      Let me know if these help on solving stuttering problem.

      Giuseppe.

  13. Thanks for the hints! (I don’t know howcome I didn’t find that github issue 1402 myself *blush*) But.. My RPi 3B+ (with CYW43455, apparently) already came prebaked with your suggestions, although the comment in /lib/firmware/brcm/brcmfmac43455-sdio.txt now reads:
    # Improved Bluetooth coexistence parameters from Cypress.
    It seems those ‘experimental’ parameters have been accepted ;-).

    I already tried disabling WiFi before I contacted you, but it did make me rethink all usage of WiFi and BT in my installation. I realized I was using cwiid (wminput) for connecting a WiiMote. Bingo! Killing that process removes the stutter. cwiid is unmaintained – maybe I’d better replace it with MoltenGamepad and see if that does not hammer BT so much.

    I learned 2 new valuable commands in the process:
    – ‘sudo ip link set wlan0 down’ to kill WiFi (‘ifdown wlan0’ does not work anymore in recent versions of Linux/Raspbian)
    – ‘hciconfig -a | grep bytes’ – a poor man’s BT traffic monitor; I could not easily find another tool. blueman and WireShark are mentioned on the web, but GUI-oriented and kinda heavy for my RPi.

    I hope others can benefit from my experiences!

  14. Thanks for your post I have applied to build my own project.
    It is a audio bluetooth transmitter based on a pi zero W.
    The audio comes from an USB microphone (mono I guess, through a cheap USB audio adapter like https://www.amazon.com/Adapter-Raspberry-external-headphone-microphone/dp/B01I5P3POO)
    I can here sound played by the VLC on the bluetooth speaker. The problem I have now is
    first : to route audio in (micro) to audio out (bluetooth device) : how can I set this connection stable and permanent, without delay or buffering (if possible)
    second : to make the system working after boot without any more user action (in CLI mode, no desktop required). I have only one bluetooth headset to connect to and “forget”. No other appli running.

    It could help a lot if you have any advice or link/tuto to reveal.
    Thanks a lot guys.

    1. This error seems to say that your speaker appears to RPI already paired, so you should try to connect. Consider that your OS is a Desktop version, for this reason some addctional bluetooth/audio package could “interfere”. This tutorial has been written for RPI OS Lite

  15. Great Article: All works well! But one thing I was not able to figure out: audio volume control! Tried amixer and pactl or pavolume.sh script. Can see the change in volume but the sound level is always the same. pls adv!

    PS. My project is to transmit blinker set tone of my motorcycle direct into my helmet ( Pi Zero detecting blinker switch and sending warntone via bluetooth to the second channel of my freecom 4 bluetooth kit from cardo). Cool, indeed, true?

    1. Hi Theodor,
      I would check only at alsamixer levels, but I understand you have already done it. I may be wrong, but if this doesn’t work I suspect that differently from a wired solution, where higher volume means higher signal power, with a bluetooth connection the volume level depends only on bluetooth final device (your headphones).

  16. HI ,
    Thank you for this article, i am fresh user for Raspberry Pi, i just buy Raspberry Pi 4(8 GB) and i need to connect headphone, i prefer it to be bluetooth but at the same time i very worried if the connection is not working.it is about my gradution project.So can you give advaice about buying bluetooth headphone or just normal one.

    1. Hi Bayan, you should be able to use any Bluetooth headset. I can’t recommend a specific one as I created this procedure with a very old headphone from a local brand.

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