How to identify the good and bad amplifier
AV amplifier is the core of the audio playback, its role is the multi-channel sound playback function. When it comes to multi-channel sound reproduction it is impossible to get away from the standard of surround sound. In the choice of amplifier must pay attention to whether the amplifier has now popular surround sound standard certification:
1, Dolby Directional Logic (Dolby prologic) Surround Sound.
2, Dolby Digital (Dolby Digital) surround sound.
3, DTS surround sound.
4, THX Surround EX surround sound (7.1 channels).
5, DTS-ES Discrete Surround (6.1 channels), and so on.
A home AV amplifier should have at least Dolby Digital Surround decoding and playback function, because Dolby Digital is the DVD Alliance in December 1997, the mandatory companion sound standard for PAL video discs, AV amplifier whether to have this feature is the basic point of user choice. Other certifications are a direct reflection of the level of the amplifier.
Evaluating an AV amplifier good or bad standard in addition to the obvious certification, there are many indicators and parameters.
1, the output power: is the amplifier connected to the speaker to get the energy, the amplifier, its rated power (amplifier in the conditions of non-distortion can be a continuous output of the rms power) is to evaluate the performance of the amplifier is a valid indicator.
2, distortion: the output of the device can not fully reproduce its input, resulting in waveform distortion or signal components of the increase or decrease is called distortion, the smaller the distortion of the amplifier, the better the sound quality.
3, dynamic range: the strongest part of the signal and the weakest part of the level difference between the equipment, the dynamic range of the equipment on the strong and weak signal response capability.
4, damping coefficient: damping coefficient refers to the load impedance and amplifier output impedance ratio, is a measure of the amplifier internal resistance to the size of the speaker damping effect of a performance indicator.
5, output impedance: the output impedance of the amplifier refers to its output terminals on the speaker to show the equivalent internal resistance, it should be consistent with the rated input impedance of the speaker.
6, signal-to-noise ratio: signal-to-noise ratio refers to the decibel difference between the audio signal level and the noise level. The higher the signal-to-noise ratio, the smaller the relative noise of the amplifier, the better the sound quality.
7, separation: separation refers to the AV amplifier in the surround sound decoder to the audio coded signal is reduced to the ability of each channel signal. Separation degree of poor amplifier will appear inaccurate positioning of the sound image, the sound field is not full, the sound image of poor coherence and other phenomena.
Perhaps these indicators let the ordinary people are puzzled, that simple point of the most intuitive is the driving ability (i.e., how much power) and amplifier weight. Although the relationship between the output power and driving force is not so direct, but has a relatively close connection, the output power is easy to find from the instructions in the indicators, 100W, 200W, 400w or even more, but the driving force some times need to go from behind these indicators to really listen to have a real say. This refers to the choice of speakers, rear amplifiers for speakers to drive, the stronger the driving ability that the more capable of driving the speakers, the more comfortable in the power output, more to explore the potential of the speakers, so the general U.S. AV amplifiers like their production of cars with large displacements, high power to drive low impedance audio is considered to be a good deal of fun. But the Japanese production of AV amplifiers occupy more than 80% of the market is also illustrated by the uniqueness of its technology, so try to use high-power rear amplifier, in exchange for a more relaxed control and instantaneous dynamics is the choice of AV amplifier is very important point. Speaking of the weight of the amplifier is perhaps the easiest to perceive, because the amplifier needs a strong power support, so the heavier the amplifier and its power supply equipment, the greater the transformer index or the use of a larger capacitor, these are the quality of the amplifier to ensure that the amplifier is heavier, and the heavier the amplifier, the better the stability to avoid unnecessary vibration caused by the impact of the sound quality.
AV amplifier purchase considerations
1, decoding function
General should choose the built-in decoder of the combined AV amplifier, at least should have Dolby Digital and DTS dual decoder to ensure that to adapt to the playback of more than enough audio and video resources.
Dolby Digital Dolbydigital (Dolby AC-3) is the United States Dolby Laboratories introduced a fully digital separated multi-channel film sound track system, also known as Dolby Digital Surround Sound, is a more advanced than the previous way of high-quality digital audio coding format. All of its channels are recorded in a fully digital way, using the highly efficient MPEG2 digital compression coding technology. Dolby Digital Surround has the following advantages: true stereo surround sound, wide bandwidth of the full audio range, complete isolation of each channel, extremely wide and controllable dynamic range, and compatibility with current sound systems.
DTS (Digital Theatre Sound) is a home multi-channel digital surround sound system introduced by the United States DTS Technologies, Inc. It improves the acoustics of multi-channel surround sound and exceeds the 16-bit quantized CD standard in terms of dynamic range and high fidelity. DTS system uses its compression ratio is not as high as Dolby Digital, adapt to a wider range of bit rates, can be compressed 18bit, 20bit, 22bit and 24bit quantization of digital audio signals (its input signal can still maintain the full dynamic range and frequency band), sampling frequency can be 48kHz, 96kHz or higher. DTS systems, like Dolby Digital, also use a 5.1-channel format, but up to 8.1 channels. In terms of sound quality, it is difficult to distinguish between DTS and Dolby Digital.The DTS system has four-channel or six-channel recorded CD disks in addition to LD and DVD disks, while Dolby Digital has only diskettes but no CD disks.The DTS system has the DTS-specific logo printed on both software and hardware.
2, power matching
AV amplifier focus is to create an ideal listening environment with visual effects, creating a realistic sense of orientation, presence and sense of shock. Therefore, the design of AV amplifier focuses more on the performance of the clarity of the dialogue and audiovisual environment of the large dynamic "burst" effect, restore or simulate the sound and picture of the sound field positioning, creating a variety of sound field atmosphere. In this way, not only requires AV amplifier frequency range as wide as possible, small distortion, high signal-to-noise ratio, good transient characteristics, sound quality, beautiful sound, etc., and pay more attention to the sound pressure level: that is, under the premise of low distortion, to ensure that the output power is large enough.
Amplifier output power in watts (W), due to the manufacturers of measurement methods are not the same, so there are a number of different names called. For example, rated output power, maximum output power, music output power, peak music output power. High-grade AV amplifier front main channel power rating is generally more than 80W to meet the requirements of the movie theater 107dB sound pressure level.
Usually the power of the amplifier is the greater the better, but the main role of the amplifier is used to promote the speaker, it should be based on the speaker needs to promote the power to determine the rated output power of the AV amplifier. In general, the amplifier and speaker power configuration standards are: under certain impedance conditions, the amplifier power should be greater than the speaker power, but not too large. In the general application of the amplifier's undistortion rate should be about 1.2-1.5 times the rated power of the speaker; and in large dynamic occasions should be about 1.5-2 times. It should be noted that the maximum output power of the amplifier and the speaker's maximum power must be matched to prevent inadvertent burning of the speaker.
3, pay attention to AV amplifier and HiFi amplifier requirements are different
Hi-Fi equipment is mainly used to listen to music, the highest purpose is to reproduce the information on the audio soft body in its original form, so the materials are more elaborate, the power is not the greater the better, the purpose of the AV equipment is to obtain the best soundstage effect, to obtain the momentum and atmosphere required by the image, and a sense of scene expressed by the image. A picture of the expressed sense of scene, so more concerned about power, dynamic response, etc., and not very concerned about the sense of music, so some very Hi-End HiFi amplifier used to do AV amplifier is not necessarily suitable.
4, try to understand the performance and sound quality, is to buy AV amplifier must link
A machine performance and quality has a lot to do, to understand the quality of the product so that the purchase of the product must be personally tried, the actual operation of a machine to understand the performance of a clear. About the sound quality, no matter how good the parameters say, how full-featured, the amplifier is ultimately used to restore the sound. What we want is not to move home and put out noise things, so buy AV amplifier before no matter how much preparation you do, personal audition is also a must. Often, the sound of the amplifier has a certain personality, and speakers with the sound may not always be good. So not only to personally audition, and it is best to connect the amplifier and their choice of speaker system field audition.
5, as far as possible to choose the new model.
Because the AV amplifier involves complex technology, which IC chip out very quickly, the new IC chip technology must be better than the old chip, so buy the newer the model can enjoy the more new technology. At the same time, it is recommended that the best choice of mid-range AV amplifier products, in order to better meet the configuration of the home theater audio-visual enjoyment needs, not to buy back to the feeling of the future after the same as chicken ribs.
6, brand and after-sales
Should be purchased through formal channels of well-known brands of products, such as Yamaha, Tianlong, Anqiao, Marantz, etc., product quality and after-sales service are relatively more secure. If you buy online, it is best to go to the physical store to audition to determine a good brand model, and then through the search of the price network than the price to choose a well-known B2C mall, the brand's official website or flagship store to buy. The AV amplifier is bought after remembering to buy a fiber optic cable, used to connect the player and the AV center, otherwise you can not use the AV amplifier Dolby Digital decoder.AV amplifier top ten brands>>