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Sonos Arc is the company's first step into the world of high-definition home theater audio, providing Dolby Atmos 3D sound.
However, despite how good this move is, there is still a problem for many people: Sonos Arc only has a single eARC HDMI input, so what does it mean if the same type of port is not available on the TV? The answer depends on the type of TV you have, the lifetime of the TV, and the types of ports available.
The HDMI Audio Return Channel (ARC) is designed to make audio flow in the opposite direction to the sound bar or home theater amplifier. HDMI ARC is designed as an upgrade to optical S/PDIF, with a maximum audio bandwidth of 1Mbps (S/PDIF is limited to around 384Kbps).
In addition to increasing bandwidth for higher quality audio, HDMI ARC also supports HDMI CEC, which means that your TV’s volume control can adjust the sound on external devices, and it also has built-in lip sync correction, although this usually requires manual Adjustment. To make it work properly.
The problem is that high-quality uncompressed audio such as Dolby TrueHD requires more bandwidth and cannot run on HDMI ARC. This is where the HDMI eARC appears, the bandwidth has increased by 37Mbps, and the lip sync has been improved.
HDMI eARC is backward compatible
, And can switch to a lower bandwidth option to be compatible with older devices. Therefore, the HDMI ARC on the TV can be plugged into the HDMI eARC of Sonos Arc.
Although technically HDMI eARC can be implemented on HDMI 2.0b ports, the reality is that only TVs with HDMI 2.1 ports support eARC. In fact, unless you bought a TV in the last 18 months or so, you are unlikely to have HDMI eARC, which means you can’t run the highest quality audio into Sonos Arc.
If you are lucky enough to have HDMI eARC (the port on the back will be marked with such a mark), you can pass a complete high-quality signal to Sonos Arc.
Compared with ordinary HDMI ports, HDMI eARC (and its predecessor ARC) outputs sound on different pins of the HDMI cable. Therefore, the sound enters the TV from the device (or application), and then the TV outputs the sound on the correct pin to the external device connected via eARC or ARC.
The connection not only requires sound, but also requires a handshake when connecting: this can solve the synchronization method of the sound and the HDMI CEC control information.
Even if you purchase an HDMI 2.1 splitter and plug a cable into the back of Sonos Arc, you will not hear any sound at all. Unfortunately, although some companies are considering creating an external speaker, there is currently no external speaker that can convert the signal to HDMI eARC.
If successful, you will effectively use an external box whose audio output will be fed to Sonos Arc and the video output will be output to your TV.
If there is only one TV with HDMI ARC, it is impossible to input the complete uncompressed audio into Sonos Arc. Instead, some form of lossy low-bandwidth codec must be used. What happens depends on the type of TV you have.
There is a little overlap, but the general rule is that if you have a TV produced before 2016, you can use Dolby Digital (the earliest standard) to compress 5.1 sound. If you have a TV produced after 2016, it is likely to support Dolby Digital Plus, which has an encoding rate of up to 768Kbps and supports 7.1 channel audio.
Dolby Digital Plus is an advanced codec designed to sound as close to the source material as possible, providing higher-quality audio than Dolby Digital, while using a wider bandwidth than Dolby TrueHD ( Dolby TrueHD) is much smaller. However, Dolby Digital Plus still uses lossy compression, so some details have been removed. Dolby TrueHD uses lossless compression.
If you have HDMI eARC, you can use any Dolby TrueHD source (such as an Ultra HD Blu-ray player) to get Dolby Atmos at the highest quality. This will move high-quality sound through the TV to Sonos ARC.
The streaming service that supports Dolby Atmos does not use Dolby TrueHD because it is too bandwidth, but uses Dolby Digital Plus to encode Atmos, which encodes between 384Kbit/s and 768Kbit/s. So if you watch Netflix or
, Then you can still get the compressed version of Dolby Atmos.
The good news here is that if your TV comes with HDMI ARC that supports Dolby Digital Plus and Dolby Atmos, the quality you get from streaming services will be the same as a TV with HDMI eARC.
When it comes to external devices, things get more complicated. Blu-ray and Ultra HD Blu-ray discs only use Dolby Atmos as part of the Dolby TrueHD audio track. As we all know, it cannot be delivered to Sonos Arc due to insufficient bandwidth. There is a workaround: if your TV itself supports Dolby Atmos decoding, such as LG’s 2018 OLED TV, the TV can decode the high-resolution panoramic sound input and re-encode it as Dolby Digital + (Dolby Digital Plus) to send to Sonos Arc.
You get a slightly compressed version of the sound, but in reality, since the changes are subtle, it's hard to hear the difference.
Unfortunately, whether the TV can encode Atmos to Dolby Digital Plus still depends on the device and its capabilities. E.g,
Dolby Atmos is included in some of its shows and movies, but when I launch the integrated Netflix application, there is no Dolby Atmos content available; using the LG Netflix App, I can Send Atmos to Arc.
Sonos does not support any DTS sound format at all. In fact, if you try to play a disc with any form of DTS sound (original DTS, DTS-HD MA or DTS:X), you will not hear any sound on Sonos Arc at all. Quite frustrating, because many discs only have surround sound in DTS audio, and no alternative Dolby Digital is provided. Arc does support multi-channel LPCM sound, which allows you to input DTS sound into the system. Please refer to my guide
For more information.
If your TV does not have any type of HDMI ARC connection, you can use the optical adapter provided by Sonos. As mentioned above, this will restrict you from using Dolby Digital for more compression, thereby reducing the sound quality. Also, you will not get Dolby Atmos.
Fortunately, there are now
help. This external box accepts HDMI input and then uses Arcana's eARC output to send video to a TV (or projector) and send audio directly to Sonos Arc. This means that if you have an old TV without eARC, you can directly send the full-quality lossless sound format to Sonos Arc.
In most cases, it can solve the main problem of Sonos Arc brilliantly: it does not have a regular HDMI input. Since Arcana has only one input, you can pair it with an HDMI switch to use multiple devices.
HDMI ARC bypassing the TV also has an additional advantage, that is, it will not have the lipstick problem like when transmitting audio through the TV: this is very obvious on systems such as Sky Q.
HDMI Arcana can also get the ARC output of the TV, so you can continue to use its built-in applications and run audio through the TV. I use LG TV's built-in Netflix App, and I can get Dolby Atmos through Sonos Arc (via Dolby Digital Plus).
This is not a perfect system, and the way it works may be a bit finicky: sometimes it will not receive HDMI ARC signals from the TV. I found that the best way to solve this problem is to use the main input device (Sky Q in my case) to turn on the TV. Then, when there is a sound from Sonos Arc to switch to the built-in application, this is a happy day. Firmware updates are provided frequently, and Fury will improve with each iteration.
Although some models have HDMI ARC ports, they are not popular on projectors. If the projector has HDMI ARC, you need to connect the playback device to the HDMI in port, and then connect the HDMI ARC output port to Sonos Arc. As far as we know, no projector supports Dolby Atmos in this way, and we cannot find any projector with an HDMI eARC port to provide the highest quality audio.
For projectors without HDMI ARC, a device that can extract audio is currently needed. The HDFury Arcana listed above will do the job and provide you with high-quality sound effects including Dolby Atmos. If the budget is tight, an HDMI extractor (such as Lindy 4K audio extractor) that can output audio through S/PDIF can do the job.
However, doing so will limit you to 5.1 Dolby Digital without surround sound. In view of the limitations of using projectors and the large lack of support for Dolby Atmos, it would be better to use other sound systems or HDFury Arcana.
