Adding Bluetooth Speakers to Linux

Playing Music on Multiple Sets of Speakers

Here was the plan: I've used a stereo audio Y cable to connect my Linux desktop both to standard powered speakers on a shelf above the computer, and to the Line In port on a receiver driving speakers in the bedroom.

The bedroom is through the wall, and I ran the speaker wire through the wall by removing the plates on the cable TV connections.

The receiver, dating from the late 1980s, was getting flakey. And the speaker wire was questionable. I wanted to avoid wires.

I would put a Bluetooth speaker on the shelf over the bed.

I also needed to add a Bluetooth transceiver to the Linux desktop. Setting it up was simple. Plug the Bluetooth transceiver into a USB port, and plug the speaker into a smartphone charger. Then bring up the Bluetooth configuration panel from the Settings menu, click to "flip the switch" by "Connection", and the Bluetooth link is good.

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The Problem

The music that was playing through the wired speakers immediately switched to the Bluetooth speakers. I could switch it back and forth, but I didn't see a way to make it send output to both the wired speakers and the Bluetooth speaker simultaneously.

The Solution — Add a Virtual Output Device

Install the paprefs command, which has it own package on Mint and Ubuntu. That command starts the PulseAudio Preferences graphical configuration tool. It needs module-gconf loaded in the sound server. Also make sure you have the pulseaudio-module-bluetooth package installed. You very likely have everything except paprefs installed already.

Run paprefs, select the Simultaneous Output tab, and check the box for "Add virtual output device for simultaneous output on all local sound cards" as you see here.

Select the New Virtual Output Device

I haven't figured out the plumbing of PulseAudio and other sound modules. Once I saw that I might be in for a long experimental struggle with various services, I simply rebooted.

Now the Sound panel from the Settings menu gave me a third Output choice. It wasn't there before. Select it.

You should now be hearing audio through both devices simultaneously.

Adjust Levels As Needed

Use the pavucontrol command to bring up a tool to configure your audio, including adjusting the relative levels of the Line Out device (wired speakers) versus the Headphones (Bluetooth speakers).

Note that the Bluetooth device likely has some latency, it will be a little behind the wired speakers. This might matter to you if you're putting your wired and Bluetooth speakers at either end of a large shared space. If so, the Advance option in this tool lets you adjust latency.

Now take the Bluetooth speakers into the other room!

If you bought a really low-end Bluetooth speaker without a volume control, you may need to make a few back-and-forth trips to adjust the relative levels.

Enjoy! Or Go Deeper

Above I have France Bleu Provence playing.

The Bluetooth player will appear in lsusb output:

$ lsusb
Bus 002 Device 005: ID 062a:727a MosArt Semiconductor Corp.
Bus 002 Device 004: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 002 Device 003: ID 03f0:c311 HP, Inc
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 006: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 005: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

You can ask for a verbose description by specifying its bus and device number. For example:

$ lsusb -v -s 001:006
[... much output deleted ...]

You can look up the vendor and device IDs at the USB ID Repository. For example, mine appears as 0a12:0001. Vendor ID 0a12 means "Cambridge Silicon Radio, Ltd", and device ID 0001 means "Bluetooth Dongle (HCI Mode)", both as reported by lsusb.

The bluez-tools package contains some useful commands, see their manual pages for details:

$ dpkg --listfiles bluez-tools | grep 'bin/'
/usr/bin/bt-adapter
/usr/bin/bt-agent
/usr/bin/bt-device
/usr/bin/bt-network
/usr/bin/bt-obex

$ bt-adapter -l
Available adapters:
desktop (00:1B:DC:06:77:A2)

$ bt-adapter -i
[hci0]
  Name: desktop
  Address: 00:1B:DC:06:77:A2
  Alias: desktop [rw]
  Class: 0x1c0104
  Discoverable: 1 [rw]
  DiscoverableTimeout: 0 [rw]
  Discovering: 0
  Pairable: 0 [rw]
  PairableTimeout: 0 [rw]
  Powered: 1 [rw]
  UUIDs: [00001133-0000-1000-8000-00805f9b34fb, AVRemoteControl, OBEXObjectPush, 00001132-0000-1000-8000-00805f9b34fb, PnPInformation, IrMCSync, 00005005-0000-1000-8000-0002ee000001, HeadsetAudioGateway, AVRemoteControlTarget, PhoneBookAccess, 00001801-0000-1000-8000-00805f9b34fb, AudioSink, 00001800-0000-1000-8000-00805f9b34fb, Headset, AudioSource, OBEXFileTransfer]

$ bt-device -l
Added devices:
onn. Indoor SPK MD GRY (F4:4E:FD:C2:C8:14)

$ bt-device --info=--info=F4:4E:FD:C2:C8:14
[F4:4E:FD:C2:C8:14]
  Name: onn. Indoor SPK MD GRY
  Alias: onn. Indoor SPK MD GRY [rw]
  Address: F4:4E:FD:C2:C8:14
  Icon: audio-card
  Class: 0x240404
  Paired: 1
  Trusted: 1 [rw]
  Blocked: 0 [rw]
  Connected: 1
  UUIDs: [AudioSource, AudioSink, AVRemoteControlTarget, AVRemoteControl, Handsfree]