HDMI Audio Extractor: Why use? How does it work?

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How does HDMI audio extractor work?

HDMI audio extractor separates HDMI input signal to the audio output and normal HDMI output. While most models only output analog stereo line levels through RCA or 3.5mm jacks. There are models that output analog 7.1 and others.

Using the HDMI audio extractor is pretty straightforward and for the average home audio or home theater user. The setup is pretty intuitive. When all is said and done, you can expect to spend around $ 20-150 plus cables depending on the capabilities of the HDMI audio extractor.

How does it work?

An HDMI audio extractor is to isolate the audio signal from the HDMI signal. Then decode and re-encode it to another type of audio signal (usually analog). In all but the rarest cases, an HDMI audio extractor is essential if you are going to convert HDMI to analog audio or any other format.

Since HDMI carries a digital signal, sending the HDMI output directly to an analog system will not create a viable audio (or video) signal. In almost every case, you can’t just get a cable that seems to convert HDMI to RCA. These cables are designed to work with devices that decode the HDMI signal before outputting.

An HDMI cable has 19 pins that carry a number of digital signals capable of carrying not only audio and video. But also things like remote control commands and device information.

These signals are HDMI specific and therefore require digital conversion for other formats. Audio will need an HDMI audio extractor to convert to other formats.

Why would you use an HDMI audio extractor?

The HDMI audio extractor makes sense anyway when you need to convert HDMI to an audio-only source. While there are times when an HDMI audio extractor might be your only solution (for example, when using an analog sound system). In some cases, there may be alternative solutions that do not include an HDMI audio extractor.

Example of using HDMI Audio Extractor

The simplest scenario that includes an HDMI audio extractor is when you need to route audio from an HDMI-only source to an audio-only receiver. If you are not only a cinephile but also an audiophile, this may apply to you as well.

If your home theater room serves as a listening room. You can opt for an optional stereo system for better music listening. If you listen to music from HDMI-only sources (Roku, Apple TV, and other media streamers). You can route it to your stereo via the HDMI audio extractor.

A slightly more cumbersome setup involves connecting HDMI-only components to a system that uses an older analog receiver. In such a case, you may want to get an HDMI splitter to route one HDMI signal to your display device and the other through the HDMI audio extractor to your receiver.

Of course, you can get around this if you want to design a setup that uses HDMI audio extraction as well as an HDMI wireless transmitter. But for now, we’ll continue to focus on one thing – a room wired setup.

Does the HDMI audio extractor degrade Sound quality?

It should not degrade audio quality. Since HDMI is a digital signal, it will remain roughly the same quality. Things that will affect the sound quality include the sampling rate capabilities of the extractor. The HDMI version your devices support, the length of the cable used to connect them.

The sampling rate is the key factor here. The sampling rate is the frequency at which a signal is received by a device. The higher the sampling rate, the more accurately a discontinuous digital signal can simulate a smooth analog signal.

A lower sample rate can mean two things for your sound. First, it means you won’t be able to reproduce higher frequencies. (Whether your speaker system can broadcast them or your ears can hear them is another story). Secondly, this means that the secondary sounds will be slightly muted. And if you don’t know what that means, you have nothing to worry about.

Maximum sampling rate

Although HDMI has had the same sampling rate capabilities since its inception. The HDMI protocol allows for different sampling rate specifications that devices may be designed to handle. This way, the audio quality will always be determined by the least performing device in your chain. Which may or may not be your HDMI audio extractor.

One factor that determines this capability is the HDMI version that the devices are using. While HDMI has always had a maximum sampling rate for single channels of 192 kHz. The aggregate maximum sampling rate has increased from 768 kHz with HDMI 1.4 to 1536 kHz with HDMI 2.0.

This means that a manufacturer can theoretically get 8 channels of audio (e.g. 7.1 audio ) without having to downsample per channel (next step is 176.4 kHz) to stay within the maximum aggregate sampling rate.

Signal path length

Another important factor that affects sound quality is cable length. This is due to the fact that when connected, HDMI-enabled devices enter into a digital handshake. That transmits information that sets the connection parameters between the two devices. One of these things is the sampling rate.

Although the devices are designed to output at a specific sampling rate. The length of the cable between them will change the amount of time it takes for the signal to travel from output to input.

When devices participate in a handshake, the signal transmitted between them is synchronized by the internal clocks of the two devices. which determines the sampling rate with which the two devices communicate.

How to select HDMI audio extractor

HDMI audio extractor selection

The HDMI audio extractor you are using should not degrade the audio quality. If you pay attention to the specs and don’t do things like unnecessarily using 25ft cables. When a 4ft cable does, you can enjoy high-definition audio without any noticeable loss in audio quality.

Generally speaking, newer HDMI audio extractors must be equipped with HDMI 2.0 or later (the latest is 2.1, released November 2017). So don’t worry about 7.1 audio sampling rates or less. There are many budget models like the J-Tech Digitial Premium (on Amazon) that support 5.1 channel extraction.

Most basic models only output stereo sound. And you probably have to splurge on a decent 5.1 or 7.1 system (and probably get a unique set of cables to connect all of your components). But prices for a good 7.1 channel extractor like the Monoprice Blackbird (on Amazon) are still in double digits rather than triple digits.

There are models that support RCA, 3.5mm, digital optical, and HDMI. In addition, there is other equipment that provides HDMI audio extraction functions in addition to other functions such as source and output switching.

When choosing a solution for extracting audio over HDMI, make sure you have an output format compatible with it. RCA and 3.5mm can be converted to analog audio signals. Like digital signals, digital optical signal and HDMI cannot be converted without equipment to decode them.

There are many reasons why you might want to use an HDMI audio extractor. Whatever your application, you should now be better prepared to determine. If the HDMI audio extractor is the right solution for you and how to choose the extractor according to your needs.

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