The new HDMI 2.1a is designed to optimize viewing content that has varying quality by improving the overall picture quality. Basically, HDMI 2.1a is HDMI 2.1 with a minor feature update called source-based tone mapping (SBTM).
Where HDMI 2.1 introduced support for eARC and uncompressed 8K signal, HDMI 2.1a brings one new feature called Source-Based Tone Mapping (via HDMI.org). This feature is a key update for HDR, though, so it could end up playing a larger part in future HDMI updates.
HDMI 2.0 has a bandwidth capacity of 18 Gbps (gigabits per second). HDMI 2.1 takes the number up to 48 Gbps, which means that HDMI 2.1 does not have to compress that much of the data and preserve a better data quality during the transmission process.
HDMI 2.1 sports a heap of new features, but the only one affecting cable compatibility is the transmission rate, which has skyrocketed from from 18Gbps to 48Gbps.
So, What Should I Do? HDMI 2.1 is only needed if you want to use HDMI with 4K over 60Hz. This applies to consoles, as on PC you can get the same performance with DisplayPort 1.4, which is readily available. So, it's likely adding HDMI 2.1 cables and expense to your setup is not something you need to worry about now.
HDMI 2.1 allows for higher resolutions like 8K and higher frame rates of up to 120 frames per second (fps). Resolution improves the clarity and sharpness of the picture, which means you can simply see more details, and have less distance to the screen or a bigger screen without noticing any pixels.
When it comes down to 4K TV, you do not need to pick up special HDMI cables. The HDMI cable standard can impact color and resolution, but newer versions are not required for 4K TV.
A 2.1 HDMI cable can be as long as 50 feet or over. As a cable with a higher frame rate, the greater the distance the signal has to travel, the more quality loss there will be. For the best length and definition balance, we wouldn't recommend going over 20 feet.
That said, HDMI is and has always been fully backward compatible. It's perfectly fine to use a TV equipped with HDMI 2.1 with an older HDMI cable. It's also perfectly fine to use a next-generation console with a TV that has HDMI 2.0. They will work, but won't be capable of outputting in 4K at 120Hz or higher.
You don't absolutely need HDMI 2.1 to reach 120Hz or even 144Hz refresh rates, but it is important for supporting both high refresh rates and high resolution at the same time.
With the myths now debunked, it's time to know the truth. Can a very expensive HDMI cable show a better picture and sound quality than a cheaper one? The quick answer is no. An HDMI cable, regardless of the materials used, can either transmit a signal or not – there's no in-between.
You're in luck — all you need is a single HDMI cable to connect your TV and soundbar enabled with Dolby Atmos (HDMI 2.0 for ARC should do the trick while HDMI 2.1 is necessary for eARC setups). This is the simplest option and will send audio directly from your TV to your soundbar.
1A ports are fine for mobile phones, but aren't suitable for tablets. To ensure you can charge a range of devices, it's best to go with 2A ports at minimum. High-power USB ports—2.4A to 5A—are available. 2.1A ports are normally sufficient, but a high-powered port will charge your device quicker.
This means that the 2.1A slot can deliver at maximum 2.1 ampere of current, more than double than the 1A slot. Ideally the 2.1A slot will fast faster (almost in half time) than the 1A slot as it can deliver more current in the same duration of time. However, it also depends on the device you are charging.
The 2.1 system is a good choice for those who want a noticeable upgrade from their standard TV speakers, but don't necessarily need total enveloping sound. 2.1 soundbars are also the better choice for smaller spaces due to their more compact profile.
HDMI 2.0 cables are all really the same, despite what some manufacturers will try to tell you with their branding – but an HDMI 2.1 cable with 48Gbps will be necessary to experience the technology's capabilities, and you'll need a compatible HDMI 2.1 port on any connecting hardware (TVs, soundbars) too.
On Apple TV 4K, you need an HDMI 2.0 or later compatible cable. To access all of the features that your Apple TV has to offer, use an HDMI 2.1 cable.
You can simply check the back of the TV to see what's written above the HDMI inputs. Although some inputs won't specifically say 'HDMI 2.1', it may show the maximum refresh rate at 4k; an HDMI 2.0 input shows '4k @ 60Hz', while an HDMI 2.1 input shows '4k @ 120Hz' and may also have an eARC label.
Like many audio, video, and data cables, HDMI cords can suffer from signal degradation at longer lengths—50 feet is generally considered the maximum reliable length.
HDMI 2.1 supports 4K at up to 120Hz natively, but it can also do 4K at 144Hz with DSC or 4:2:0 subsampling.
If you are wondering about whether your existing HDMI cable will work, it is possible that you will not need to upgrade to one that is “4K-compatible.” Any HDMI cable up to five meters in length labeled “high speed” should be able to handle the increased bandwidth of 4K signals.
The majority of HDMI connectors in use today are the Type A (Standard), Type C (Mini) and Type D (Micro) shown below. HDMI Type B (Dual Link) was developed for very high-resolution displays but was never used.
When you have invested in a high quality home theater or audio/video system, the last place you want to skimp is the HDMI cable. For a minimal expense, a high quality HDMI cable can make a noticeable difference in the video and audio quality.