Raspberry Pi Bluetooth Speaker: A2DP Audio Streaming Build

Building a Bluetooth speaker with a Raspberry Pi is one of the most satisfying weekend projects in the maker community. Using the A2DP (Advanced Audio Distribution Profile), you can stream high-quality stereo audio from any smartphone, tablet, or laptop directly to your Pi-based speaker system — with full control over the audio chain, amplifier, and enclosure.

In this tutorial, we’ll cover the complete build: choosing your hardware, configuring Bluetooth A2DP on Raspberry Pi OS, setting up BlueALSA or PipeWire for audio routing, and connecting to an amplifier or DAC HAT. By the end, you’ll have a fully functional wireless Bluetooth speaker.

Understanding A2DP: The Bluetooth Audio Profile

Bluetooth has several audio profiles, and understanding which one to use is essential before diving into the build:

• A2DP (Advanced Audio Distribution Profile): High-quality stereo audio streaming from a source (phone) to a sink (speaker). This is what we’re implementing. Supports SBC codec by default; AAC and aptX with additional libraries.
• AVRCP (Audio/Video Remote Control Profile): Allows play/pause/skip controls. Often implemented alongside A2DP.
• HFP/HSP (Hands-Free/Headset Profile): For voice calls and microphone input. Not used in a pure speaker build.

For our project, we need the Pi to act as an A2DP sink — it receives audio from your phone (the A2DP source). This requires BlueZ (the Linux Bluetooth stack) plus an audio middleware layer (BlueALSA or PipeWire) to route Bluetooth audio to ALSA (the sound system).

Hardware Requirements

For this build, you’ll need:

• Raspberry Pi with built-in Bluetooth (Pi 3B, 3B+, 4B, Zero W, Zero 2 W, Pi 5) — or a USB Bluetooth dongle for older models
• Audio output: Either the Pi’s 3.5mm audio jack (adequate for testing), a USB DAC (better quality), or a DAC/amplifier HAT (best quality)
• Amplifier: A Class D amplifier board or a speaker with built-in amplification
• Speaker driver(s): 4Ω or 8Ω speakers
• Power supply: 5V/3A (Pi 4) or 5V/5A (Pi 5) — Bluetooth and audio processing increase power draw
• MicroSD card (16GB+), keyboard, and monitor for initial setup

Setting Up Raspberry Pi OS

Start with a fresh Raspberry Pi OS installation (Bookworm or Bullseye recommended). Use Raspberry Pi Imager to flash the OS, enable SSH and Wi-Fi in the imager’s advanced settings, then boot and SSH in.

First, update the system:

sudo apt update && sudo apt upgrade -y

Enable audio output. If using the 3.5mm jack on a Pi 4 or earlier, ensure the audio driver is enabled:

sudo raspi-config
# Navigate to: System Options → Audio → Select the appropriate output

For Raspberry Pi 5, audio routing is handled differently through the PipeWire stack that ships by default in Raspberry Pi OS Bookworm.

Method 1: BlueALSA (Lightweight Approach)

BlueALSA (Bluetooth ALSA backend) is a lightweight daemon that bridges BlueZ Bluetooth audio to ALSA. It’s ideal for headless builds or when running on Pi Zero W with limited resources.

Step 1: Install BlueALSA

sudo apt install -y bluealsa

On Raspberry Pi OS Bookworm, the package may be named bluez-alsa-utils:

sudo apt install -y bluez-alsa-utils

Step 2: Configure BlueALSA to start as A2DP sink

Edit the BlueALSA service to specify A2DP sink profile:

sudo systemctl edit bluealsa
# Add:
[Service]
ExecStart=
ExecStart=/usr/bin/bluealsa -p a2dp-sink

Step 3: Make the Pi permanently discoverable

sudo bluetoothctl
# In bluetoothctl:
power on
pairable on
discoverable on
agent on
default-agent

To make discoverable at every boot, edit /etc/bluetooth/main.conf:

[Policy]
AutoEnable=true

[General]
DiscoverableTimeout = 0
PairableTimeout = 0

Step 4: Auto-connect audio routing

Create a script that automatically routes newly connected Bluetooth devices to the speaker output:

#!/bin/bash
# /usr/local/bin/bt-connect-audio.sh
# Called by udev/systemd when device connects
DEVICE=$1
bluealsa-aplay -B 250000 --profile-rc a2dp "$DEVICE" &

Method 2: PipeWire (Modern Approach, Recommended)

PipeWire is the modern audio stack on Raspberry Pi OS Bookworm (Debian 12). It handles Bluetooth audio natively and provides much lower latency than BlueALSA. If your Pi runs Bookworm, this is the recommended approach.

Step 1: Install PipeWire Bluetooth support

sudo apt install -y pipewire pipewire-audio-client-libraries 
  pipewire-pulse wireplumber libspa-0.2-bluetooth

Verify PipeWire is running:

systemctl --user status pipewire pipewire-pulse wireplumber

Step 2: Enable A2DP sink role in WirePlumber

WirePlumber is PipeWire’s session manager. Create a config file to enable A2DP sink:

mkdir -p ~/.config/wireplumber/bluetooth.lua.d
cat > ~/.config/wireplumber/bluetooth.lua.d/51-bluez-config.lua << 'EOF'
bluez_monitor.properties = {
  ["bluez5.enable-sbc-xq"] = true,
  ["bluez5.enable-msbc"] = false,
  ["bluez5.enable-hw-volume"] = true,
  ["bluez5.roles"] = "[a2dp_sink]"
}
EOF

Step 3: Restart PipeWire services

systemctl --user restart pipewire pipewire-pulse wireplumber

Step 4: Auto-accept Bluetooth connections

Install and configure bt-agent for automatic pairing:

sudo apt install -y bluez-tools

# Create systemd service
sudo tee /etc/systemd/system/bt-agent.service << 'EOF'
[Unit]
Description=Bluetooth Agent
After=bluetooth.service
PartOf=bluetooth.service

[Service]
ExecStart=/usr/bin/bt-agent -c NoInputNoOutput
Restart=always

[Install]
WantedBy=bluetooth.target
EOF

sudo systemctl enable --now bt-agent

Now any device can pair and connect without requiring confirmation on the Pi.

Audio Output Options

The audio chain after Bluetooth decoding determines sound quality:

Option 1: 3.5mm analog output — Built-in PWM audio on Pi. Works but has audible noise floor and limited dynamic range. Suitable for testing only.

Option 2: USB DAC — Plug in a USB audio adapter. Much cleaner output than the built-in jack. ALSA will recognize it automatically. Set as default audio device in /etc/asound.conf.

Option 3: I2S DAC HAT — Best audio quality. I2S (Inter-IC Sound) is a digital audio bus that bypasses the Pi’s noisy power circuitry entirely. Popular I2S DAC HATs include the HiFiBerry DAC+, Pimoroni Audio DAC SHIM, and IQaudio DAC HAT. Add the appropriate overlay to /boot/config.txt:

# Example for HiFiBerry DAC+
dtoverlay=hifiberry-dacplus

After adding the overlay, PipeWire will automatically detect the I2S DAC as the default audio output device.

Pairing and Testing Audio

With the Pi configured, pairing from your phone is straightforward:

1. Open Bluetooth settings on your Android or iPhone.
2. The Pi should appear as a discoverable device (name defaults to your Pi’s hostname, e.g., raspberrypi). To change the name: sudo hostnamectl set-hostname MyBTSpeaker
3. Tap the Pi’s name to pair. If using bt-agent with NoInputNoOutput, it will auto-accept.
4. Once paired, select it as your audio output and play music.

To test audio from the command line:

# Check audio devices (PipeWire)
pw-cli ls Node

# Play a test tone
speaker-test -t wav -c 2

If you hear audio through the connected speaker, your A2DP sink is working correctly.

Troubleshooting Common Issues

Device pairs but no audio plays: Check that wireplumber is running (systemctl --user status wireplumber). Also verify the Bluetooth device profile is A2DP, not HFP — on Android, long-press the Bluetooth device and check the active profiles.

Audio stutters or drops: Increase the BlueALSA buffer size, or check for Wi-Fi/Bluetooth coexistence issues. Pi’s built-in Wi-Fi and Bluetooth share the same chip and can interfere. Try using USB Wi-Fi and keeping built-in Bluetooth, or vice versa.

High latency: SBC codec has ~100-200ms latency. For video sync this can be problematic. Enable SBC-XQ (high quality SBC) in WirePlumber config for better quality without switching codecs.

Frequently Asked Questions

Can I connect multiple Bluetooth devices simultaneously to the Raspberry Pi speaker?

BlueZ and PipeWire do support multiple simultaneous Bluetooth connections, but A2DP audio mixing depends on your audio stack configuration. With PipeWire, multiple A2DP source devices can connect and their audio will be mixed automatically. With BlueALSA, you need to run multiple instances of bluealsa-aplay. In practice, most use cases involve one device streaming at a time.

What audio quality can I expect from Raspberry Pi A2DP?

The default SBC codec provides ~320 kbps equivalent quality — noticeably lower than wired audio but perfectly acceptable for casual listening. With SBC-XQ (high-quality SBC extension), quality improves significantly. The Pi itself doesn’t limit audio quality; the bottleneck is the Bluetooth codec and your speaker/amplifier hardware.

Does this work with Raspberry Pi Zero W?

Yes. The Pi Zero W has built-in Bluetooth and can run BlueALSA as an A2DP sink. However, the Zero W’s limited CPU and RAM mean PipeWire may be too heavy. Use BlueALSA with a lightweight ALSA setup instead. Audio output requires a USB audio adapter since the Zero W lacks a 3.5mm jack.

How do I rename my Raspberry Pi Bluetooth speaker?

Change the hostname with sudo hostnamectl set-hostname YourSpeakerName, then restart the Bluetooth service: sudo systemctl restart bluetooth. Also update /etc/hosts to reflect the new hostname. The new name will appear in Bluetooth device discovery on your phone.

Can I add physical buttons to control playback?

Yes. Using the AVRCP profile alongside A2DP, you can send play/pause/skip commands. Connect physical buttons to GPIO pins and use a Python script with the dbus library to send AVRCP commands to the connected device. The playerctl command-line tool simplifies this: playerctl play-pause.

Conclusion

Building a Raspberry Pi Bluetooth A2DP speaker is a genuinely rewarding project. You get full control over the audio chain — from Bluetooth codec configuration to speaker driver selection — and end up with a custom speaker that outperforms many commercial options in flexibility and repairability.

The PipeWire approach on Raspberry Pi OS Bookworm is now the recommended path: it’s well-maintained, handles Bluetooth audio natively, and integrates cleanly with ALSA and JACK if you want to extend the project further.

Build your Raspberry Pi Bluetooth speaker today! Explore our full range of Raspberry Pi boards, HATs, and accessories at Zbotic to get everything you need for your audio project.