Looking into my retro tech closet, I can see how easy life used to be – or not. Game consoles, Divx players, network receivers and so on had dozens of outputs to offer something for every situation: S-Video, Scart, Cinch, Composite, optical/coaxial (SP/DIF). All you needed was an incredibly large box of cables and adapters for everything and there was always a quirky input somewhere on the TV or receiver that made the right connection with the right cable.
HDMI simplified everything. You now only need one cable for everything. My television has (almost) only HDMI connections, modern consoles and 4K players such as Apple TV 4K (test report) or Fire TV Stick (test report) still have a power input and an HDMI output. That’s all you need. That’s true as long as you want to connect one device with an HDMI output to another with an HDMI input. Connect console and stick to TV, done. As soon as it gets even slightly more complex, the simplicity is gone.
Beamer instead of TV? No problem, also works with HDMI. But then the sound is gone. Most projectors don’t have speakers, and very few at least output the sound to connect an AV receiver. AV receivers solve many problems if they have enough HDMI inputs. And are new enough – because my AV receiver in the living room is great, but it can’t do 4K. So throw it away? It’s out of the question.
Console, Apple TV, Blu-ray player & Co. must therefore be connected directly to the television, which then outputs the audio signal back to the receiver. This works as long as the TV has enough HDMI inputs (usually the case) and the sound is also output without errors (rarely works). I have an unpleasant jerking sound with squeaky background noise when the 4K signal gets to the TV and the sound then flows digitally to the receiver – whether via HDMI with ARC (Audio Remote Channel) or via the optical SP/DIF output of the television. Of course, this is an isolated case, but there are many of them – and we show a possible way of dealing with them.
HDMI Audio Splitter / Audio Extractor
If you want to extract the sound from a signal, you can use a special HDMI adapter. They have an HDMI input and an output and an additional audio output, which outputs a jack socket for headphones, cinch sockets for an analogue stereo signal or SP/DIF for a digital 5.1 signal, depending on what is required.
What exactly you need depends on the cable situation on site and the required HDMI standards. Such an extractor costs 15 to 20 euros in the best case. The devices support the HDMI 1.4 standard and output music and sound both digitally and analogously; the limitation lies in the resolution: full HD is not a problem, 4K is only possible with a reduced refresh rate (30 Hz).
If you want to transmit a 4K image to a TV or projector, you should pay attention to HDMI 2.0 or HDMI 2.1 when buying an HDMI audio extractor. You have to pay at least 25 euros for such an adapter. As with the 1.4 model, there are HDMI inputs and outputs, as well as an analogue and a digital audio output.
No matter what the resolution, audio extractors require power. In the best cases, you can get it via a USB connection. Power adapters are usually not included, but you don’t need them either: almost every television and AV receiver has at least one USB port free, to which you can connect a stick for firmware updates, for example – the splitter then also gets its own from it Energy. Incidentally, USB-C is still a rarity, most HDMI distributors and HDMI adapters want to be supplied with energy via micro-USB or mini-USB and bring a cable with a USB-A plug.
HDMI switcher or HDMI switch
If you have more HDMI players than suitable inputs, an AV receiver often takes over the job of the switch. However, the devices are large and comparatively expensive – and if you already have a good-sounding hi-fi system, buying a new one doesn’t necessarily make sense when a simple HDMI switch is actually enough.
Corresponding devices are available from around 10 euros. You have one HDMI output and two, three, four, six or even more inputs for different HDMI sources. Depending on the model, switching is done with a mechanical switch, with pushbuttons, IR remote control, automatic or a combination of these things. Again, it is important to pay attention to the HDMI standard. Cheap models manage full HD and 4K with limitations. For a small surcharge, there are switches that can also handle 4K resolution at 60 Hz.
Since the automatic switching often doesn’t work as well as you would expect – for example, when a Fire TV stick or an Xbox turns on briefly because of a firmware update, although you’re watching a film on Blu-ray – and the If the way to the switch is not up-to-date, we would recommend a device with a remote control. If you like, you can use smart infrared transmitters such as the Broadlink RM Mini 3 with Alexa connection to activate the routines for switching through using a smart home app or voice command.
Incidentally, better-equipped HDMI switches come with the audio splitter function: This 65-euro model from Amazon, for example, is a switch and audio extractor in one.
HDMI-Splitter
The HDMI splitter is sort of the opposite of an HDMI switch. If you want to fire several outputs from one input, for example monitors in several rooms at the same time or projector and television at the same time, you need an HDMI splitter (also called 1-in-2-out adapter). The simplest adapters of this type (from about 8 euros) even work in both directions – they either make one output from two inputs or supply two outputs from one input signal.
This is easily sufficient for normal audio and video signals. However, it can become complex when HDCP copy protection and its newer versions such as HDCP 2.2 are used – for example when playing a Blu-ray or a 4K stream. HDCP is intended to ensure that the HDMI signal between the player and the output device is encrypted throughout – if it is used, you cannot just connect several televisions or monitors.
HDMI cable
Which cable is the right one? While it used to be very simple – after all, digital transmission is digital transmission – the world of HDMI cables has become significantly more complex. Only the HDMI connector is always the same. And because the subject is so complex, we have dedicated our guide to HDMI cables from 5 euros: Differences, HDMI 2.1, 4K, HDR to this topic.
Conclusion
I have an audio extractor in the living room because my hi-fi system is not 4K-capable and the TV’s sound output is causing problems. In the office I have an old Full HD projector with a single HDMI input that is connected to a switcher with an audio extractor – so I can use multiple HDMI devices (Fire TV Stick, Xbox and Nintendo) without having to reconnect to have to. An RM Mini 3 takes care of switching, which I can control by voice via Alexa. It’s good for comfort and the environment – it means my old hi-fi amps can still be used occasionally even though one doesn’t even have HDMI – and the other isn’t from the 4K era.