In the current era of enhanced audiovisual experiences, HDMI plays a crucial role in most audiovisual products. To meet consumers’ demands for high-quality audio, HDMI 2.1 introduces an additional feature, eARC (Enhanced Audio Return Channel), allowing the transmission of digital audio through HDMI cables. While supporting sound formats like Dolby TrueHD and Atmos, it can also handle 8-channel speakers.

Although modern high-end TVs boast eARC support, some purportedly compatible models face challenges due to design oversights, leading to the inability to output 8-channel audio. This compromises the functionality of eARC and leaves consumers dissatisfied, impacting the brand’s reputation.

Risk and Solution for HDMI TV Sound Output Quality

The eARC specification relies on two sources. One is derived from HDMI input, for instance, when TV’s HDMI1 input is linked to PS5, allowing PS5’s audio to be sent to the amplifier through HDMI3 input, which supports eARC. The second source is from non-HDMI input, as seen when using Netflix with Ethernet cable. Ordinarily, due to speaker limitations, the TV only accepts 2-channel LPCM or AC3. However, when connected to eARC-supported amplifier, the TV synchronizes and updates the audio specifications in its EDID. This empowers the TV to transmit Dolby DTS-HD and 8-channel audio to the amplifier.

Allion collaborates with major TV manufacturers and has an extensive portfolio of testing cases. In one instance, a client reported that their product had obtained HDMI certification, yet they received customer complaints about the TV’s sound quality. Allion provided problem isolation and debugging services. Upon our team’s analysis, it was discovered that the product had overlooked updating the EDID mechanism. While EDID update is an optional feature and doesn’t affect certification, it significantly impacts eARC functionality. Following our recommendation, the client updated this feature, resolving the issue promptly.

Drawing insights from the aforementioned case, it becomes apparent that the eARC functionality of a television, lacking the capacity for EDID updates, imposes limitations on audio output, restricting it to just two channels. Allion provides advanced eARC testing equipment capable of determining a product’s EDID update capability. This ensures that eARC can support a broader range of audio formats and multiple channels, aligning with the product’s intended functionality.

Our services are designed to proactively address any potential issues, ensuring a certified product doesn’t encounter complications related to unsupported audio channels.

Faster, Easier, Better: The Most Trusted HDMI Product Testing Consultant

Allion is an official certification laboratory authorized by the HDMI Forum. We have a complete range of HDMI testing equipment that can ensure compatibility amongst different kinds of HDMI products, helping you with your quality control along the way. Allion can also provide clients with fast and accurate evaluations that effectively shorten schedules for certifications. With plenty of experience, Allion provides the best consulting services for our clients and helps them eliminate issues they may encounter. This ultimately reduces the possibility of users returning their purchased products.

  • A Comprehensive HDMI Compliance Test Solution: Passing certification tests can ensure signal transmission quality. It also allows manufacturers to avoid being audited by the HDMI Association
  • Customized Testing and Consulting Services: HDMI monitors with repeaters were designed because of market demands. HDMI certification alone cannot guarantee the quality of your products. Allion can help clients conduct and pass compatibility tests, user scenario simulations, and more, ensuring these products are compatible with one another.


With our rich testing experience and collection of testing equipment, we can provide clients with fast and accurate certification planning that effectively shortens the certification schedule and helps clients quickly obtain HDMI certification. Allion is an official certification laboratory authorized by the HDMI Forum. We also have a complete range of HDMI testing equipment that can ensure compatibility amongst different kinds of HDMI products, helping you with your quality control along the way.

  • Quickly provide product development certification strategies with rich testing experience and collection of testing equipment
  • Quickly obtain logo certification (HDMI)


Allion has a complete range of HDMI hardware certification testing equipment and testing environments. With our testing solutions, we can ensure each client’s certification process is qualitative, quantitative, and reproducible. Through Allion’s service, we can assist our clients in obtaining accurate test results easily, ensuring the quality and performance of their products.

  • Provides more accurate results
  • Provides professional issue isolation and debugging support for our clients to make products


Not only does Allion have professional teams with decades of experience, but we also know how to design quantitative tests and user scenario simulations, allowing our clients to comply with requirements and user expectations. Allion’s professional teams can also provide suggestions for product modifications, assist with supplier management, and help with specifications requirements from international associations during product development. This further enhances the quality of our client’s products, ensuring high standards that comply with international specification requirements.

  • Provides a better and more complete experience for brands to establish ODM ecosystem plans
  • Provides more complete user scenario testing solutions


If you have any requirements or questions, please contact us.