DACX8 multi channel GPIO audio card, no sound

[connorturansky-svg]

Hi FPP Team,

I’m working on a permanent installation using a Raspberry Pi 5 with a HiFiBerry DAC8x and have hit an audio issue I’m hoping you might recognise.

FPP Version and Hardware
FPP v9.5.2 (v9.5 branch) running on a Raspberry Pi 5 with a HiFiBerry DAC8x (output-only model)

Board: Raspberry Pi 5
Audio HAT: HiFiBerry DAC8x
OS: Raspbian GNU/Linux 12 (Bookworm)
Kernel: 6.12.57-v8+
Use case: Permanent 8-channel audio installation feeding line-level outputs into external amplifiers

Describe the bug and Steps to reproduce

The DAC8x is detected correctly by both FPP and ALSA, but no audio is produced from any output. Playback appears to initialise, but speakers remain silent.

Steps to reproduce:

1. Flash the official FPP v9.5.2 image for Raspberry Pi 5

2. Install the HiFiBerry DAC8x onto the GPIO header

3. Edit /boot/firmware/config.txt and set:
   dtoverlay=hifiberry-dac8x
   dtparam=audio=off

4. Boot FPP

5. Go to Settings → Audio/Video

6. Set Audio Output Device to:
   snd_rpi_hifiberry_dac8x

7. Save and restart FPPD

8. Try:

   • FPP test audio
   • Playing a sequence with audio
   • Running speaker-test -c 8 via SSH

Result:

• Device initialises and is selectable
• Playback appears to start
• No audible output from any jack

Additional behaviour observed:

• Earlier tests sometimes produced: Transfer failed: Bad address
• Currently speaker-test -c 8 runs and cycles through channels but still produces no sound
• Mono test files fail with channel-count errors, suggesting the device expects multichannel input

Expected behavior

Audio should be output through the DAC8x line outputs (at least channels 1+2 on the first jack) when using:

• FPP test sound
• Sequence playback
• ALSA speaker-test

Since the card is detected and selectable, expected behaviour is normal 8-channel audio playback.

Additional context

Hardware checks:

• Amplifier and speakers confirmed working (audible hum when touching input)
• Amp connected to the first DAC8x jack (closest to the GPIO header)
• Volume turned up during testing
• Board powers normally

ALSA behaviour:

• DAC8x detected as card 0: snd_rpi_hifiberry_dac8x
• 8-channel stream initialises at 48000Hz S16_LE
• No mixer controls present (expected for this board)
• Playback starts but produces total silence

FPP audio settings tested:

• Channel layout:

  • Stereo
  • 7.1

• Output format:

  • Default
  • 48000/S16
  • 48000/S32

• Various buffer and period sizes

• Restarted FPPD after each change
  ``
  System troubleshooting already attempted:

• Disabled onboard audio and HDMI audio

• Forced ALSA default to card 0 via /etc/asound.conf

• Stopped FPP and tested directly with speaker-test -c 8

• Tried different audio formats and rates

• Confirmed the device opens and playback begins but produces no sound

Log observations:

• Earlier logs showed references to snd-soc-dummy-dai
• Behaviour suggests ALSA stream starts but I²S/TDM output never becomes active

FPP_Logs_20260207.0936.zip

[patdelaney]

Please note that none of the developers have access to one of these boards for testing I did a quick google search and Pi-Shop.us is out of stock. To get one shipped from Europe for the board and shipping is $105.00.