Home theaters generally include two categories: audio systems and video systems

The video system is relatively simple, player, TV, projector.

A. Audio system includes, player, amplifier, speaker.

There are many types of audio players, such as PC computers, PS3, HD hard disk players, set-top boxes (that is, those that everyone often uses).

Power amplifier full name: Audio power amplifier (here only AV power amplifier)
1. Power amplifier has AV power amplifier, stereo power amplifier. AV amplifiers, also known as multi-channel surround sound amplifiers, can process integrated video signals in addition to audio signals. As early as the 90s to 2009 VCD/DVD era, AV amplifiers only had Dolby Pro Logic, Dolby AC-3 and DTS 5.1 surround sound audio decoding. It is a lossy compression surround sound technology. The regular AV amplifiers that appeared after 2009 basically have Dolby true-HD and DTS-HD next-generation lossless surround sound audio decoding. Both are 7.1 channels. Supports high bitrates above 1.5Mbps, twice as much as DVD 768kbps. Therefore, DTS-HD and true-hd are called full-code lossless. DVDs are called SD half-code lossy. Due to the high bit rate of next-generation audio, the data cable used by the player to transmit to the AV power amplifier can no longer use coaxial and optical fiber cables, but can only use HDMI cables. Among them, the maximum bitrate of DTS-HD can reach 30Mbps, and Dolby true-HD 18Mbps. Of course, Blu-ray DVD with next-generation audio can also be backward compatible with DVD audio, which means that Blu-ray DVD has a 7.1 audio track in addition to a next-generation 5.1 audio track. The advantage of this is that the old AV amplifier will not have the embarrassment of not being able to decode when playing the latest movie.

The picture above is a typical next-generation 7.1-channel AV power amplifier wiring diagram, with coaxial, optical fiber input in the middle. On the right is the HDMI next-generation audio video input. The function of HDMI input is to separate the audio signal from the audio signal that is not decoded by the front-end signal source, and then amplify and output it to the next level through internal decoding, that is, the speaker emits sound. In addition, the video stream in HDMI is output from the HDMI of the power amplifier back to the video terminal, which is usually a TV and a projector. Advanced AV amplifiers basically come with ARC backhaul function, and the principle is similar to what I said.

2. Speakers

Speakers are physically simple, which can be divided into active and passive. Active is to build the amplifier into the speaker, which has the advantage of low cost and space saving. 80% of the consumer audio market is of this type. Passive is a speaker without a power amplifier. Only the crossover and horn are inside. Such a speaker has high playability and is suitable for audiophiles who have a certain pursuit of audio, such as the author. Passive speakers can be combined with amplifiers with different performance and timbre to change the final output. Of course, the cost of passive speakers is relatively high. Generally, high-end speakers are passive.

All speakers with external power supply are active speakers, which is very easy to distinguish. The opposite is passive. Look at the picture below

3. Player (i.e. signal source)

Home theaters basically use high-definition hard disk players, built-in hard disk compartments, and early with DTS/Dolby AC-3 dual decoding. Now the mainstream HD players are DTS-HD, Dolby true-HD dual decoding, and then Dolby Atmos and DTS X more advanced audio decoding. ATMOS is currently the most advanced audio surround sound technology. Previously, DTS was a little more technologically advanced. Now feng shui takes turns. Simply put, DTS X and ATMOS are upgraded versions of DTS-HD and true-HD. The sound field is more realistic, and the sense of enveloping, dynamics, resolution, etc. have been greatly improved. The main thing is to add 7 or more Sky speakers to the original 1.2 base supreme, and then add one subwoofer. Of course, the difficulty of this debugging and optimization has also increased, which is a relatively big challenge for audio manufacturers and audio practitioners. As a result, only a few first-line AV amplifier brands have such strength. For example, Japanese brands such as Denon, Yamaha, American Marantz and domestic Tianyi. There is also a more classic AV power amplifier in the Japanese system, which just closed down last month, which is embarrassing!

Early HD hard disk playerThis
is the high-definition hard disk player bought by the contemptible people in 2010, with optical fiber coaxial output, HDMI output, analog stereo, color difference component output. Realtek 1073 chip decoding. Now the functions of Blu-ray original disk players are generally similar, and the built-in software of hard disk players represented by 1073 and 1185 Realtek chips is embedded firmware. Now basically all Android system decoding chips are HiSilicon RT1619 and Realtek chips, supporting the next generation DTS-HD, DTS X, Dolby true-HD, Dolby Atmos, of course, DVD era 5.1 decoding backwards compatible. Moreover, the online playback function is more optimized than before, and the definition is high. Of course, the latest shows all need to be charged. Support poster wall, automatic download of subtitles and more.

Then there are audiophiles who may use a PC host as a signal source. Such a host is called HTPC. In the early years, there was still a group of such players tossing around. Theoretically, HTPC is a little more cumbersome to operate than HD players. Players are required to have a good understanding of computers and software players. Such a PC host requires a small size, usually built with ITX ultra-tiny motherboards. The CPU can use mainstream i5 memory 8G. The most important thing is that the hard disk capacity is as large as possible, generally 4TB or more. What must be said here is that many people think that HTPC must be equipped with a discrete graphics card, and here I want to say it. HTPC discrete graphics card is really not necessary, now both Intel and AMD integrated graphics support source code output lossless audio signal to AV power amplifier. Discrete graphics cards really don't mean much.

The red HTPC host is contemptible DIY. There is no need for a discrete graphics card at all, and the core graphics card source code is directly output to the AV amplifier.

Look at the image above, Intel monitor audio. The appearance of this project means that this amplifier supports source code input, in other words, not only PC, HD hard disk players, xbox/ps3, set-top boxes can be output through HDMI on this amplifier, decoding the surround sound effect. It must be said here that most of the domestic set-top box TV boxes are basically only responsible for exporting video signals, especially low-end ones below 200 do not have source code output surround sound tracks. Of course, this is not important, because buying such a TV box is to see ordinary movies chasing online TV series, not pursuing acoustics.

4. Speakers

Speakers for home theaters are basically divided into floor boxes, bookshelf boxes, satellite boxes, etc. The minimum configuration of home theater is 5.1 speaker system, then 7.1, and now high-end 7.1.2/7.2.4 and other types. 5 full-band speakers plus a subwoofer, the reason why it is called 0.1 channel, the subwoofer is also called a subwoofer, and the theoretical frequency response range is 20-200HZ. IN FACT, THE SUBWOOFER CAN BE AS LOW AS 30HZ, AND THERE IS NO OBVIOUS ATTENUATION, BASICALLY THOUSANDS OF HIGH-END GOODS. Subwoofers are now all active, built-in amplifiers. Of course, the larger the power of the same grade, the better, and the larger the horn caliber, the better! Of course, the higher the cost. In order not to produce resonance, the subwoofer cabinet must be made very thick. The caliber of household subwoofer horns is generally in the range of 10 inches - 12 inches, which is too large to occupy a place and is not suitable for household use.

5.1 Speaker system layout drawing

FL and FR represent left channel speakers and right channel speakers respectively. These two speakers are also called the main speaker, C means the center speaker, mainly responsible for the movie dialogue replay, SL and SR are called left surround speakers, right surround speakers, responsible for the sound stage playback behind the movie

(In practice, the surround speaker will be hung on both walls or on the back wall)

7.1 Speaker system

On the basis of the original 5.1, two side surround speakers are added, making the surround sound effect coherent and the sense of enveloping stronger

7.1.4 Speaker system

On the original 7.1, four sky speakers have been added, surround sound field, sense of enveloping, separation, and resolution from the listener front and back, left and right, up and down are very perfect immersive experience, of course, such a speaker system is also quite expensive. Commissioning and construction are also more complex and professional! Generally, a professional team is required, involving acoustics, building acoustics, electroacoustics, computer software-assisted audio testing and so on.

B. Video systems

The display terminal is basically a TV and a projector. Of course, you must use a computer monitor to see it, but the experience is not ideal. After playing in Zhihu for so long, I found that many self-media or other netizens will think that the TV comes with what HDMI, and there is no need to buy AV power amplifiers for optical fiber coax? This is not to say that it is completely wrong. It should be said that the TV with HDMI optical fiber coaxial source code output capacity is relatively limited, if you have the kind of DTS and AC-3 decoding AV power amplifier in the early days, you do not need to replace the latest DTS-HD and Dolby true-HD power amplifier. After all, TV is a picture display product, and the audio decoding or next-generation audio decoding output ability is still relatively amateur. Those who sell echo walls or already want to sell echo bars will say, I won't buy an echo wall with panoramic sound decoding? Despised people think that it can be, but the effect is not very good. A TV output capacity is limited, the source code output is just a dispensable function, the manufacturer will not use a good output chip for you to use. In addition, 99% of TV users will not use this feature at all. Second, due to its own physical characteristics, even if he can decode the panoramic sound, the sound output of the Dolby next-generation audio track is not satisfactory. 2-inch speaker, weak power amplifier circuit, even the so-called first-line international XBL brand is just that. Even their own audio indicators mislead consumers, and some openly challenge the law of conservation of energy. The subwoofer power consumption is only 25W, and the speaker output actually dares to mark 120W, unable to complain!