Introduction to Smart Home Home Theater and Background Music Products and Performance

DVD player

A DVD player is also known as a video disc player. It is a device that plays video and sound in an optical disc and is a device that can generate an AV signal source in a home theater. The DVD player is an audio-visual device produced by the combination of digital video technology, digital audio CD player technology and computer technology. It integrates laser technology, digital technology, and precision machining technology. It is a typical consumer electronics product for optical-mechanical integration. In the home theater, there are mainly DVDs, EVD players and Blu-ray players.

DVD player

The DVD is intended to be a digital video disc. It uses the lvIPEG-2 technology standard to record stored signals. A DVD player usually refers to a DVD player that is used exclusively for playing video-recorded DVDs. DVD players are a further development and enhancement of VCD players. Regardless of the sharpness of the image or the beauty of the sound quality, DVD players have greatly improved. Its image clarity can reach more than 500 lines. It adopts 5.1 channel stereo surround sound effect with Dolby Digital (AC-3). DVD player not only has karaoke function, but also is compatible with VCD and CD discs. High-rate digital audio-visual equipment.

2.EVD player

EVD's full name is "a new generation of high-density digital laser video disc system" and is an upgraded product of DVD players. It is a digital optical disc system with independent intellectual property rights in China and a national standard in the field of digital optical discs in China. EVD player. Can provide users with more clear video programs, EVD system based on the original DVD technology to speed up the code stream nearly doubled, the image resolution to 5 times the DVD, to achieve more powerful sound, more beautiful subtitles And more flexible choices. The main technical features are as follows.

In terms of video, the system not only achieved standard definition, but also achieved 8 different video quality from YCD quality to high definition, and fully supported various usage requirements and usage environments including high-definition digital television. Can be used directly as test equipment and home entertainment equipment in the production of high-definition digital television.

In terms of audio, the system uses EAC audio compression technology with proprietary intellectual property rights, which not only fully supports mono, dual and 5.1 channels, but also outperforms current DVI in audio quality. Dolby AC-3 for the license fee.

Moreover, it is even more important that EVD has obtained 22 patents, developed 5 sets of software, and has been tested by a third party. Compared with Super VCD and DVD systems, the technology has obvious advantages, which fills the storage and playback aspects of domestic high-definition programs. Blank is a groundbreaking achievement in China. Among them, the audio compression algorithm (EAC) with independent intellectual property rights is used to generate audio that is superior to Dolby AC-3 quality at the same code rate, which has reached the advanced level of audio compression in the world.

3. Blu-ray player

Blu-ray Film Case is a high-definition DVD player developed and developed by a Japanese company. It uses a 405-nm (nano, one-hundredth of a millimeter) blue light as the laser for reading and writing DVDs (CDs). By the end of 2007, Sony was Our country introduced the first high-definition player equipped with Blu-ray DVD. It uses 7.1 surround channel audio output. The video display format is 1080i (1920X1080, interlaced), and the video signal output is the number of movie-like play frames of 24 frames per second.

The diameter of the Blu-ray Disc player is 12cm, which is the same as that of a normal DVD disc. This type of optical disc uses 405nm blue laser to record and play up to 27GB of video data on a single-sided single-layer disc, which is more than 5 times the capacity of existing DVDs. The capacity of DVD is generally 4.7GB, which can be recorded. 13 hours of regular television programs or two hours of high-definition television programs. Blu-ray Disc uses MPEG-2 video compression technology.

HD projector

HD projector, also known as high-definition projector, is a device that can project images or video onto the screen. It can be connected to computers, DVD players, Blu-ray players, and high-definition digital TV set-top boxes through different interfaces. HD video signal.

According to different projection technologies, home HD projectors used in home theaters mainly include 3LCD projectors, DLP projectors, and LCOS projectors.

1. 3LCD projector

LCD (liquid crystal projector) projection technology is currently dominated by three-chip, so the industry is widely known as 3LCD technology. The 3LCD projector uses a 3-chip LCD (HTPS) that produces a brighter, natural, soft-to-eye image. The three primary colors of light are controlled by the respective liquid crystal display panels of R (red), G (green), and B (blue) and synthesized colors, so that the color of each point faithfully reproduces its primary color. 3LCD technology is represented by Epson and other manufacturers.

Such as Epson EH-TW3300C projector main parameters are as follows.

1) Projection size: 30-300in.

2) Screen ratio: 16:9.

3) Projection Technology: 3LCD.

4) Projector Features: Interactive.

5) Brightness: 18001m (lumens).

6) Contrast: 25000:1.

8) Number of colors: 1.07 billion colors.

2. DLP projector

The working principle of the DLP (digital light transmission processor) is to use a method of processing many tiny mirrors on a substrate to make pixels. Each tiny mirror represents a pixel. The input signal is used to control the tilt angle of the reflective surfaces of the small reflectors, thereby controlling the reflected direction of the reflected light, so that the reflected light enters the desired optical path or deviates from the optical path. This way of modulating the image is called DLP technology.

DLP technology is a patented technology of TI (Texas Instruments, USA). The projector based on DLP display technology first appeared in 1996. Its imaging device is a DMD (Digital Micromirror Device). The DMI chip contains thousands of micromirrors. Each mirror represents one pixel. The on or off state represents the lightness and darkness of the pixels in the image. The light beam passes through a color wheel (color separation device) that rotates at a high speed and is projected on the DlvID and then projected on the large screen through the optical lens. At present, DLP technology is owned by the TI company, which is also the sole supplier of DIvID chips. DLP is the most common monolithic type. Three-chip DLP projection glass is used for expensive high-end applications. DLP technology is represented by BenQ and other manufacturers.

The main parameters of the BenQ Wi070+ projector are as follows.

1) Projection size: 40-235in.

2) Screen ratio: 16:9.

3) Projection Technology: DLP.

4) Projector Features: 3D.

5) Brightness: 2200 lm (lumens).

6) Contrast: 10000:1.

7) Standard resolution: 1920 X 1080.

8) Number of colors: 1.07 billion colors.

3. LCoS projector

LCoS (liquid crystal attached silicon. Also referred to as silicon-based liquid crystal) is a matrix liquid crystal display device based on a reflective mode and having a very small size. This matrix is ​​fabricated on a silicon chip using CMOS technology. The size of the pixel is from 7μm to 20μm. For megapixel resolution, this device is usually smaller than lin. The circuit of the active matrix provides a voltage between the electrodes of each pixel and the common transparent electrode, separated by a thin layer of liquid crystal. The electrode of the pixel is also a mirror. The incident light passing through the transparent electrode is modulated by the liquid crystal and the photo-response voltage will be applied to each pixel electrode. The reflected image is optically separated from the incident light and enlarged by the projection objective onto a large screen.

The projector with LCoS technology does not pass light through the LCD panel but uses reflection to form the image. The light utilization efficiency is 40%. Compared with other projection technologies, the biggest advantage of LCoS technology is its high resolution. The projector products using this technology will also have certain advantages in terms of brightness and price. Compared with transmissive LCD projectors and DLP projectors, LCoS projectors have the advantages of high light efficiency, small size, high aperture ratio, and mature manufacturing technology. They can easily achieve high resolution and full color. which performed. Since the LCoS size is generally 0.7 in, the related optical instruments are also greatly reduced in size and the total cost of the LCoS-PTV is greatly reduced. Currently, HTPS-LCD only has the patent rights of Sony (SONY) and EPSON. DLP is the exclusive patent of Texas Instruments, and LCoS has no patent right.

For example, the main parameters of the Sony HW40ES LCoS projector are as follows.

1) Projection Technology: LCoS.

2) Projector Features: 3D.

3) Contrast: 100000:1.

4) Standard resolution: 1920 X 1080.

5) Projection light source: Ultra-high pressure mercury lamp.

6) Lamp power: 200W.

7) Technology type and specification 3 X 0.61in (15.4mm) SXXI) (silicon crystal reflective display) panel.

4. Interface

The source of the video signal for a home HD projector determines that it must have a rich interface, as shown on the rear interface of the Epson EH-TW3300C projector. Considering the need to play HD video, the HDlvlI interface is an essential interface. DVD players, etc., can be output through the component video interface, and the image color effect is closest to the signal source level: In addition, the computer is also an important playback device, and a home projector with a DVI interface must be selected. As for the audio output, due to the need to set up a home theater, the audio output of the projector is not necessary.

Projection Screen

The projection screen, also known as a projection screen, is a tool used to display high-definition images and videos in home theaters. When purchasing a home theater projection screen, you will find that almost all brands of home theater projection screens will give two basic optical parameters, that is, gain and viewing angle. These two parameters will directly affect the imaging quality of the projection screen and are two key factors in the projection screen of the theater.


Gain is actually a physical quantity used to measure the efficiency of the screen's reflected projection light. Its formulation is very strict. Firstly, magnesium carbonate coating material is used as the standard reference coating. The intensity of reflected light A is measured at the central viewing angle, and A is set as the standard reference value. Then, the measurement result of the projection screen under the same condition is set as B, and the ratio of B/A is the gain value of the projection screen. If the calculated ratio of a projection screen is 1.0, it is called a gain value of 1.0, which means that the amount of light reflection of this projection screen is the same as the value reflected by the standard reference paint. In addition, due to the problem of viewing habits, people generally claim that a projection screen with a gain of 1.5 or less is a low-gain projection screen, and a screen with a resolution of 1.5 or more is a high-gain projection screen. However, care must be taken not to confuse the negative gain with the low gain. Not all low-gain projection screens have negative gain.

2. Visual angle

The view angle is actually related to the gain and is similar to the concept of measuring the characteristics of the projection screen. It is also a parameter closely related to the intensity of light reflected by the projection screen. The viewing angle can be divided into horizontal viewing angle and vertical viewing angle according to different viewing positions. In general, due to the small change in vertical viewing angle at the time of viewing, the horizontal viewing angle is usually emphasized. In terms of horizontal viewing angle, it can be divided into maximum viewing angle, half-value viewing angle and 1/3 viewing angle.

3. The relationship between gain and viewing angle

The relationship between gain and viewing angle is relative. The smaller the gain, the larger the viewing angle. On the contrary, the greater the gain, the smaller the viewing angle. For example, a projection screen with a gain of 1.0 can reflect the incident light evenly in all directions, and the same light intensity value can be obtained from different angles. The high-gain projection screen will only focus on the axial region and deviate from this region. The light intensity value will drop rapidly.

4. The best viewing distance

The ratio of the viewing distance when viewing 16:9 HD programs to the width of the projection screen is generally between 1.37 and 1.69. The average value can be considered as 1-5. If you cannot place a seat at a distance of 1-5 times the screen width, please Reduce the size of the projection screen to achieve the 1.5 standard, then self-test and adjust, and finally get the best viewing distance.

AV power amplifier

The AV power amplifier is a home appliance that is used to enhance multi-channel signal power to drive the speaker sound. Without the signal source selection, volume control and other auxiliary functions, the power amplifier is referred to as the latter stage. The AV power amplifier is a core device in a home theater system. In addition to all the functions of an ordinary stereo amplifier, it also adds multi-channel power amplifiers and surround sound decoders (such as Dolby Pro Logic, Dolby AC-3, etc.) and DSP sound field processors; and it is equipped with various AV connections. Program source input and output terminal mouth function switch, and some also built-in AM / FM tuner.

The composition of the AV power amplifier. It mainly includes the selection of signal sources, signal processing and multi-channel power amplification. The selector of the signal source can select the input signal source, which can be a video recorder, a video player, a television or other program source. The signal processor can perform various processing and processing of audio signals. This part of the actual equipment is very rich and varied. The multi-channel power amplifier can perform final power amplification on each channel audio signal to drive each speaker system.

The signal processors now include Dolby Pro Logic surround sound decoders, Dolby Digital (AC-3) and DTS decoders, and other digital audio signal processors. They are very different from traditional preamp audio amplifiers. For example, Dolby Digital (AC-3) decoders can decode digital surround signals and reproduce surround sound effects, creating a 360. In the sound space, its sound is very directional, and the sound moves with the screen to change the orientation, making the viewer feel as if it is in the film plot and feel the kind of overwhelming, imposing surround sound field of a large-scale movie theater, realizing a realistic picture and The perfect combination of dynamic sound effects. It must be stated, however, that the prerequisite for creating this effect is the use of multi-channel surround sound discs and surround sound box systems.


Many types of speakers, according to the structure can be divided into open type speakers, enclosed speakers, inverting speakers, horn speaker and labyrinth speaker; according to purpose and performance can be divided into ordinary household speakers, hi-fi speaker, monitor Speakers, movie projectors, and theater speakers; powered speakers can be divided into active and passive speakers, powered speakers with power transformers, signal processing circuits, and power amplifiers; passive speakers are not equipped with power supplies and related circuitry. Its function is completed by a professional power amplifier, so the real HiFi class speakers and home theater speakers are very different from the computer multimedia active speakers.

Active speaker can be connected with DVD, MP3. MP4, TV, video camera, computer, game console, mobile phone and PDA. The passive speaker must be combined with AV power amplifier. Its performance is better than a single one. Source speakers, so home theater systems use passive speakers.

The frequency range of the audio system is 20Hz to 20kHz. The human ear cannot hear ultrasonic waves above 20 kHz, but one can feel it: Similarly, people can feel it for subwoofers below 20 Hz. In general, aircraft roars, rumbling of guns, piles, thunders, footsteps of dinosaurs and trolls in movies, etc., all contain very low frequency components. The human ear can't hear these frequencies, but it can be seen that the subwoofer's cone is vibrating and there is a feeling of air and air waves hitting the person. Many audio sources have a minimum frequency of less than 100 Hz and can reach 20 Hz, even a few hertz. These low frequencies are the real bass. In an audio playback system, if these low-frequency information cannot be reproduced, the atmosphere of a large movie theater cannot be truly experienced, and there is no sense of reality in the storyline. In order to be able to play super bass in a normal room, a subwoofer playback system should be set to a low frequency signal below 10 Hz. The 40-80Hz low-frequency audio is called subwoofer, and 20- 40Hz low-frequency audio is called subwoofer. The two can be called super bass. After setting up the subwoofer playback system, the intensity and flexibility of the low-frequency audio are enhanced, the layering and shocking of the sound field are enhanced, and the artistic appeal is enhanced. If you lose or lack the replay of this band, the sound will be dry and the liveness of the music will disappear or diminish.

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