The best solution to enhance your movie-watching experience at home: Allion’s audio interoperability tests

As display technology advances, high-quality sound experiences are also getting prevalent, TVs, displays, projectors, and home theater speakers are becoming essential in setting up home entertainment systems.

Recent years, AV specifications are becoming more versatile, thereby offering companies and consumers in various ways in building a new home entertainment ecosystem with innovative applications of surround sound technologies.

Using Dolby Atmos as an example, Dolby first launched the Dolby Pro Logic 5.1 with only 5 sound channels. In April 2012, Dolby introduced Dolby Atmos, the first-ever movie surround sound technology that mixes audio elements into a single audio object without adopting the replaced channel dependency. With the latest Dolby Atmos 24.1.10, it can support up to 24 channels.

With Dolby Atmos, users can place their speakers anywhere in a three-dimensional space, which allows users to design speaker locations and movements, bringing users an immersive surround sound experience.

To further enhance the Atmos experience, Dolby Laboratories also launched the brand-new codecs Dolby ED2, which is an update of Dolby E and is backward compatible. Together with professional Metadata (PMD), Dolby ED2 enables a more compelling surround sound experience.

Figure 1: Home Theater Setup with Overhead Soundbars

Multidimensional Audio Experiences for Home Theaters
In 2014, Dolby Laboratories brought audio experience to the next level by introducing Dolby Atmos for Home, which supports up to 24 channels and 10 overhead channels that can simultaneously process 128 audio objects.

In the 2018 Worldwide Developer Conference, Dolby also announced that the latest tvOS will be supporting Dolby Atmos, bringing consumers an even more immersive sound experience at home as if they were in theaters.

DTS:X, which was introduced by DTS back in 2015, is also an object-based sound technology designed for commercial and home theaters. The DTS:X also provides listeners with lifelike, multi-dimensional audio experiences. Though it shares similar features with Dolby Atmos, the DTS:X claims to be a flexible codec that can give listeners the same effects as Dolby Atmos for Home without the overhead speakers.

However, is it that easy to build a perfect entertainment system at home?

So you went to an AV appliance store to get a decent audio output device, you studied the specifications of the products on your wish list, and you got professional advice from the clerk, and with all the hard work you found yourself the perfect audio output device that you just need.

So you took it home, only to find out that the speaker is not working as it should be. Instead of having the perfect audio performance, you can only hear the hisses, the hums, and the buzzes…

Getting solutions at Allion Test Labs
With years of experiences in audio testing, Allion understands that audio quality is an essential factor to better entertainment experiences.

While testing Dolby Atmos and DTS:X, we notice that speakers do sometimes suffer from crackling noises. As our case study indicates, with plenty of sound channels, it can be quite challenging to locate audio issues in the Dolby Atmos system, and the same goes for DTS:X.

However, at Allion Test Lab we have the necessary testing devices to perform audio output testing based on consumers’ requirements. According to the analysis report derived from the Issue Database at Allion, we notice that most issues are caused by peripheral devices and AV technical problems.

Some typical audio and video issues include:

Figure 2: Home Theater Ecosystem Setup

1. Audio outputs out of sync/ Malfunction in channel output
Consider the following scenarios

• When you are playing a movie, the voice suddenly goes off while the background music is playing normally…
• When you are playing a movie, the channels are out of sync
• The sound cracks as you pause, fast forward, rewind, or turn devices into sleep mode
  The above issues indicate that the AMP/AVR has interoperability issues with the playing source (the video) while decoding or changing status.

2. No displays of image, subtitles or preview windows
In addition to product functionality tests, Allion also stimulates regular user scenarios. We understand when watching a movie, some people would like to skip forward because they can’t wait to see the next plot.

Our team stimulates this typical user behavior and finds out that sometimes when you move the time bar to see the preview window but nothing shows, or sometimes the subtitles would just disappear once you connect your devices together.

3. AV out-of-sync when a piece of connected equipment is turned off
When you connect TV and AMP to play videos, have you ever encountered the following issues?

• Instead of continuing from where you left, the video starts from the beginning
• The speakers’ volume suddenly goes up when you turn off the AMP
• TV remote works fine when you connect the TV to the soundbar, but when you switch to AVR, the TV remote fails to control the AVR, however, things do work in the other way around. If you connect your TV to the AV, then the soundbar, the TV remote is able to control both the AVR and the soundbar.

These malfunctions might be related to interoperability issues between the encoding of AV signals and HDMI CEC. Different brands often encounter interoperability issues, and we would highly recommend vendors to conduct validation tests for product interoperability to avoid user dissatisfaction.

Conclusion
We are seeing a trend where more and more families are embracing prominent audio experiences, for example, utilizing Dolby and DTS surround sound systems at their homes.

As consumers are demanding for more high-end audio output products, vendors need to make sure that their devices are interoperable with the latest audio specifications to win consumers’ trusts.

The causes to the typical AV issues varies, some are related to AVR codecs, whereas some are interoperability issues of HDMI CEC. These issues can only be eliminated through meticulously designed testing.

As audio output devices advance with new technology, Allion offers localized, customized sound testing methodologies to help vendors eliminate potential risks, as well as to satisfy the needs in different markets.