HDMI stands for High Definition Multimedia Interface and has become an inextricable part of home cinemas and home entertainment systems. When the interface was first introduced in 2003, it was cause for celebration by anyone looking to simplify his or her home entertainment experience. That’s because as a digital replacement for analogue interfaces, HDMI enables the simultaneous transmission of picture and sound. This means that two separate dedicated cables for audio and video can be replaced by one. But HDMI doesn’t just simplify the cable matrix of home cinema systems, it improves the quality. The latest versions even support a picture resolution of 4096 x 2560 pixels and can transmit up to eight sound channels.
In short, HDMI is the “missing link” for home entertainment systems, allowing them to keep up with ever-improving audio and video standards. To keep pace with these improvements, the HDMI standard itself is constantly evolving. Just as with software, these improvements are referred to as versions 1.0, 1.1, etc.
HDMI 1.4 with Audio Return Channel
Audio Return Channel, or ARC, is an extremely useful function supported by just about every standard television that greatly simplifies home entertainment connectivity. ARC enables two connected devices to not only receive audio signals via HDMI, but to send them back in the opposite direction. In instances where the television is the source of the signal such as with smart TVs, televisions with built-in DVD players or any instance when the audio is coming “upstream” from the TV to the audio system instead of the “downstream” path (whereby the television is the receiver of content), the ARC feature in 1.4 HDMI cables means that you won’t need a separate cable to transmit audio back. The HDMI cable takes care of both streams. This is a good option with receivers to which sound systems and a Blu-ray players are attached. In these configurations, the picture and sound can be sent to the television via the antennae cable, and the sound from the television can be sent back to the A/V receiver or amplifier and from there to the sound system. This flexible arrangement of multiple devices is all possible thanks to ARC.
It’s also, of course, possible to transmit a signal from a Blu-ray player to a receiver and on to a sound system and television. An additional advantage is that, in contrast to analogue picture and tone which is always susceptible to disruption, signals supported by HDMI are transmitted without interference and in top quality. Supported by HDMI version 1.4, ARC and has been available since 2009.
The only thing that might interfere with the quality of the signal transmission is the length of the HDMI cable. Unlike analogue signals which hold up well over large distances, digital signals run over HDMI cables have their limits. As a rule of thumb, the best signal quality can be attained by a cable length of no more than 5 meters and transmission without disruption can be expected with cables up to 20 meters in length. After 20 meters, you can expect the signal to degrade and the picture and sound quality to greatly diminish. A signal booster can help carry signals if cables of this length are necessary. A signal booster, also known as a repeater, is simply a device that is connected to two HDMI cables which regenerates the signal received from the source before passing it on. An additional electrical connection is generally not necessary. HDMI boosters can enable lengths of up to 30 meters.
HDMI CEC: An end to remote control chaos?
CEC, short for Consumer Electronics Control, allows the user to control multiple devices with just one remote. This spells an end to: “Honey, can you pass me the remote? … No, no – not that remote.” It’s now possible to connect all devices including televisions, TV receivers, A/V receivers, Blu-ray players, game consoles, and sound systems via HDMI and to then control all devices centrally with a single remote via CEC. The functionality of CEC, however, is not only dependent on the HDMI cable but on the device itself; and while CEC has been part of HDMI since version 1.2a was released in 2005, but it’s only recently that most devices have begun to include it.
Because of the delayed implementation on the part of most manufacturers, it’s seldom the case that all devices found in a typical home cinema system that are connected with HDMI will also support CEC. Originally, CEC was conceived as a universal interface and although it is used by many manufacturers, they often use a different name for it. Philips, for instance, calls it “EasyLink,” LG refers to is a “Simplelink” and Sony has named it “BRAVIA Sync.” Teufel Audio, however, simply refers to it as CEC or ARC/CEC in its product descriptions.
The remote function works across all devices – providing that all devices support CEC – in the following manner: Once a device and the devices to which it is connected are switched on, they will automatically find a common channel. Once, for instance, the television, Blu-ray player and sound system are all connected by a common channel, they can all be controlled by a single remote.
Coda: Connect with HDMI for a simple setup & better quality
To answer the title question, everyone who wants a home entertainment system that supports the latest standards, is capable of delivering uncompressed HD signals and multiple audio channels, and uses a minimum of cables is well advised to purchase devices with HDMI interfaces. As the most important additional features included in HDMI cables, it’s also wise to look out for ARC and CEC. Although ARC is now standard in contemporary televisions, CEC has been unevenly adopted by consumer electronics manufacturers. When it’s supported by all devices in a home entertainment system, CEC greatly improves the usability of the system. It is therefore recommended that consumers check for CEC compliance before buying.
All pictures: Property of Teufel Audio