Mu-so Gen 2 — no audio via HDMI / eARC from TV

Mu-so Gen 2 — no audio via HDMI / eARC from TV

Overview

The Mu-so Gen 2 supports HDMI ARC / eARC input for TV audio. When a customer reports no audio via HDMI from their TV, this is almost always a TV configuration issue rather than a fault with the Mu-so. This article covers the diagnosis and bench test procedure used to confirm whether the unit is at fault.

Symptoms

  • No audio from the Mu-so when TV is the source via HDMI
  • TV audio plays through TV speakers instead of Mu-so
  • Mu-so does not recognise the HDMI input
  • Intermittent HDMI audio — works sometimes but not consistently

Step 1 — check TV settings first

Before assuming a unit fault, verify the following on the TV:

  • eARC enabled: On the TV, go to Sound Settings and confirm ARC or eARC is enabled on the HDMI port connected to the Mu-so. The exact menu path varies by TV brand — check the TV manufacturer's manual.
  • HDMI-CEC enabled: CEC (Consumer Electronics Control) must be enabled on the TV for eARC to function correctly. This setting is often labelled differently by brand (e.g. Samsung: Anynet+, LG: SimpLink, Sony: Bravia Sync, Panasonic: VIERA Link).
  • Audio output set to external: Ensure the TV's audio output is set to HDMI ARC / eARC or "External Speaker" and not "TV Speaker".
  • Correct HDMI port: Not all HDMI ports on a TV support ARC/eARC. Confirm the Mu-so is connected to the ARC/eARC-designated port (usually labelled on the TV).

Step 2 — bench test procedure (for service agents)

If the customer insists the TV settings are correct, perform the following bench test before accepting the unit as faulty:

  1. Connect the Mu-so to a known-good Samsung TV (or equivalent) using a high-speed HDMI cable that supports eARC
  2. Enable eARC on the Samsung TV (Settings > Sound > Sound Output > HDMI eARC)
  3. Enable HDMI-CEC (Settings > General > External Device Manager > Anynet+)
  4. Play audio from the TV and confirm it routes to the Mu-so
  5. Also test Naim App controls (volume, source selection) while eARC is active

In the case documented from Westan's ticket history, bench testing with a Samsung TV and eARC confirmed the Mu-so was fully functional. The fault was in the customer's TV configuration.

Step 3 — if the bench test also fails

If the Mu-so does not output audio via HDMI eARC on a known-good TV and cable:

  • Check the HDMI port on the Mu-so for physical damage or debris
  • Perform a factory reset of the Mu-so and retest
  • If the fault persists, log a hardware fault ticket with Westan Naim support

Contact

Naim AU/NZ support: naim.support@westan.com.au

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