How to choose speakers and power amplifiers

Recently, home theater has gradually become the main force in the home appliance industry. I believe many working-class people and ordinary people also want to have a drink, enjoy a blockbuster and listen to a good song in their spare time. If you want to buy a home stereo or a home theater, but you don't know much about these products in the market, this article may just give you some help.

AV and HIFI

Home theater, also known as AV center, A of "AV" refers to Audio (audio) and V is Viden (video), and the AV system is configured with the playback of audio and video signals as the primary premise. Both HIFI and AV have one thing-playback software, and it must be as accurate and realistic as possible.

So is AV compatible with HIFI (High Fidelity Playback System)? This problem has troubled many audio lovers and even enthusiasts. In fact, as early as 1994, when AC3 (Dolby Digital Surrounding System, also known as DD) was just emerging, Dolby Laboratories had an unattainable requirement for the speakers of AC3 system: in order to make the replayed signals have a high degree of consistency and audio-visual orientation, at least five identical full-band speakers that can replay 20 Hz-20 Hz should be used for center, front and rear respectively. You should also have at least one subwoofer that can replay signals below 30HZ. There are very few speakers that can meet this requirement now. Even if you find a speaker that can really play back 20 Hz-20 Hz signals, the price will probably make you dumbfounded!

Compared with Dolby Laboratories, HIFI is not an organization, and the HIFI system has never had any requirements or specifications for a set of equipment. In other words, no matter what kind of stereo or cannon you have, as long as you think it belongs to HIFI, it belongs to HIFI. Therefore, before you buy audio products, you must understand a substantive problem: AV is much more demanding and more expensive than HIFI. Home theater and HIFI are completely incompatible, because HIFI enthusiasts require "original flavor and high fidelity" for music playback, while AV has a standardized description of the whole system, and the positioning is more difficult to adjust than dual-channel HIFI system.

So, does your expensive AV system or the home theater you want to buy really meet the requirements of Dolby Labs? If you can't meet the requirements of Dolby Laboratories, you should at least have the authorized logo of Dolby Laboratories. This is actually a compromise, and the sound itself is a compromise! Even though we know that what we bought home is not a real home theater. Some friends will say: I don't need to be so professional. In fact, you don't know that AC3 and DTS are designed for professional cinemas, and THX has very professional requirements for the system and environment. At present, only 100 cinemas in the world have obtained THX certification. It can be seen that playing AV well is not as simple and easy as some beginners think, and few amateurs have the listening environment conditions required by DTS and THX standards. Now most of the so-called home theaters are far from the real THX, DTS and AC3, and our home movies are just some surround sound effects.

I don't mean professional, but ask: to what extent can you compromise on distortion? What kind of distortion can you accept? If you buy a cinema just to be a facade, I advise you to give it up, because the cost is not as tasteful as buying a piano. If you don't know enough about the purchase, collocation and brand of audio, then the author will teach you how to buy a cinema.

First, teach you to choose a speaker.

Undeniably, in the history of the development of audio equipment, speakers have always lagged behind power amplifiers and sound sources. As far as the current technology is concerned, "high fidelity" can only be a relative "high fidelity". In the whole set of equipment, the biggest distortion is the speaker. The vibrating basin of the horn generates air vibration under the current of the power amplifier, so we hear the sound, but the movement of the vibrating basin produces higher harmonics, which causes serious distortion to some short sounds, which is called transient distortion. Relatively speaking, the transient response of bookcases is obviously better than that of floor-standing speakers, but the disadvantage of small bookcases is that the strength and momentum of playing back music are far less than that of floor-standing speakers. Therefore, some floor-standing speakers often use several small-sized speaker units instead of a large-caliber speaker unit to integrate the advantages of small bookcases and floor-standing speakers, learn from each other's strengths and improve the quality of sound playback. The quality of the power amplifier directly affects the playback quality of the speaker. Experienced enthusiasts often build a complete sound system according to the selected speakers (like the foundation of a house) just like building a house, which is not only scientific and reasonable, but also saves a lot of detours and saves the cost of changing machines. In the middle and low price range, bookcases have become the first choice for many enthusiasts because they are easier to control and suitable for the listening environment of ordinary families. Theoretically, if the listening area is less than 20 square meters, it is better to choose a bookcase, because I have to consider the standing wave reverberation of the room. If the speaker is too big and the standing wave is heavy, the reproduced sound will be chaotic. If the listening area is more than 20 square meters, you can consider a floor-standing box or a large bookcase. No matter how big the room is, the sound absorption characteristics of the room sound should be considered, and the acoustic treatment and swing of the room should be done well, which is the basis of beautiful sound.

Almost every speaker manufacturer has its own style and sound base positioning. British speakers are soft and pleasant, and the connection of each frequency band is relatively balanced, which is suitable for most consumers' listening habits. American speakers are enthusiastic and bold, and the sound base is tough and bright; French speakers are famous for their luxurious sound base and excellent air sense, while Danish speakers are loved by enthusiasts for their high definition and high density. When buying speakers, you should buy those well-known brands, such as the common British mission and B&; W, Spando (Spanda), Tianlang (Tianlang), AE, Wo Fei Da (Le Regal), Chu Qing (After Rain), etc. American JBL, British finidi, Tyre, etc. , French Triangle, Jmlab (Strong Wave), Danish Dynamo Jamo (Zunbao), Canadian Mirage (Milac), Energy and so on.

Domestic speaker products have different styles. Well-known brands include hivi, Shenzhong, Hewlett-Packard Cyclone, Ho's, Australian Whale and so on. The speakers of these manufacturers are generally reassuring in quality and technology. Friends who support domestic products can pay more attention to the products of these manufacturers.

Pay attention to an index problem when buying. In terms of rated power, the nominal power of general manufacturers is strict, usually "recommended power amplifier power". In fact, the power index of the speaker is of little reference value, while the sensitivity is marked when the power amplifier outputs the sine wave signal of 1W power 1KHZ. The sound pressure value obtained one meter parallel to the speaker is generally 86 dB-a civilian product. The higher the sensitivity, the easier it is to drive, and the higher the sound pressure series obtained at the same power.

The impedance of the speaker is in ohms. Usually, the lower the impedance of the speaker, the harder it is to push. The output voltage of audio equipment will change with the change of load impedance. In fact, audio equipment with high output impedance outputs less current than audio equipment with low output impedance. When the electronic tube machine is connected to the power amplifier of the sound box, the sound box whose nominal impedance is equal to or close to its output end should be selected, while the transistor power amplifier has no such restriction and can be connected to the sound box with any impedance. For low-priced speakers, it is recommended to choose speakers with impedance of 8 Ω or higher. Theoretically, the center and surround speakers should be exactly the same as the main speaker, but considering the actual situation of ordinary consumers, if conditions permit, I suggest you choose the center and surround speakers with the same brand as the main speaker. If the budget is limited, it is not bad to choose domestic well-known brand speaker manufacturers in Central, such as HP Cyclone and Australian Whale.

Second, buy a power amplifier

Common power amplifiers are divided into Class A, Class B and Class B. Among them, Class A power amplifier has the advantages of no cross distortion and switching distortion, and the harmonic components are mainly even harmonics, which are very pleasing to the ear, with heavy bass, soft and warm midrange, clear and tidy treble and good layering. However, due to the low efficiency of class A amplifier and the high cost of the whole machine, the device works at high current and high temperature for a long time, which is easy to cause problems in reliability and life, and most of the users are old enthusiasts with certain qualifications. When class A and class B (also called class AB) amplifiers are driven at low level, the amplifiers work in class A state, and when the driving level increases, they will switch to class B operation. The advantages of Class A and Class B amplifiers are higher efficiency than Class A. Although the distortion is greater than Class A, they are still the most widely used samples of transistor power amplifiers. Most AV amplifiers are designed according to Class A and Class B. When purchasing AV amplifiers, we should not only pay attention to their output power, but also consider their output current. Theoretically, the greater the output current, the better the control of the speaker. The signal-to-noise ratio in the power amplifier index refers to the signal-to-noise ratio, and the useful components of the signal are often compared with the intensity of noise. The higher the signal-to-noise ratio of equipment, the less noise it produces. The signal-to-noise ratio of household audio-visual equipment should be at least above 90dB. The nominal amplification power is generally expressed by W, but we should pay attention to its nominal conditions: for example, 8 Ω, 100W(A-weighted root mean square), and if it is 6 Ω, 100 W (A-weighted root mean square), it will be much smaller than the former. This should attract the attention of consumers.

At present, the AV amplifiers on the market are mainly Japanese brands, such as MARANTZ, SONY, Teac, Denon and Onkyo. There is not much difference in individual quality and function at the same price. The key is to choose the direction of your own voice in the collocation with the speaker. AV equipment in Europe and America is expensive, rare in the market and low in cost performance, so it is not recommended here. It is worth mentioning that recently, domestic brands of AV amplifiers have greatly improved their sound quality and sound quality compared with the past, and their cost performance is extremely high. Famous domestic brands include Zhong Shen, Spark and Ke Song.

Third, the source of sound (video).

At present, the mainstream film source is mainly DVD player, because the technology of Japanese brand DVD player is mature, and the imported brand DVD player with the same price is better than the domestic brand DVD player in image quality. Some video sources are compatible with the new generation audio format "DVD-AUDIO" or "SACD". Whether you are an enthusiast or not, I don't approve of buying this compatible machine. First, the cost has increased. Second, because video sources are scarce and expensive. Thirdly, because "DVD-AUDIO" and "SACD" are new-generation pure audio formats, compatibility with these formats in DVD players can only be one of the selling points. Neither the technical requirements nor the sound quality can be compared with the special "DVDAUDIO" or "SACD". If you want to enjoy music in the AV system at the same time, it is more rational to buy a pure CD player alone at present. But it depends on the grade of the equipment. Compared with the sound quality of DVD replay, CD players with a price of more than 1000 yuan, whether imported or made in China, will not bring you too many surprises. There are many models to choose from at a price of around 3000 yuan. Because the key technology of DVD is still in the hands of some foreign manufacturers, the technology is very mature, so I suggest you buy DVD players of imported brands such as Sony, Pioneer, Panasonic, Toshiba, Philips and Yamaha, and you should also pay attention to avoid repeated investment when purchasing, because the current AV amplifiers are equipped with DD and DTS dual decoding systems. So when buying a DVD player, you don't have to buy a DVD player with double decoding, but also a karaoke function, picture browsing and so on. Without these functions, the cost of DVD players will be reduced. As long as the picture is satisfactory, the DVD player you bought is the greatest success. Do not blindly pursue some unnecessary functions. If you save money in function, you can buy some discs to enjoy at home, or buy some wire configuration equipment.

Finally, I would also like to mention the equipment collocation problem that the old voice often talks about: some friends often pay great attention to the quality of single equipment, but ignore the personality of these high-quality equipment. For example, a friend who likes neutral timbre, whose speaker has a thin sound background, should find some amplifiers with thick sound background (such as marantz) to drive them to learn from each other. On the other hand, if the sound base of the speaker is relatively thick, find some high-frequency bright amplifiers to promote it (such as Tianlong). If he just likes thick or bright timbre, he must adjust it carefully according to his personal taste. In the process of matching, it also involves the fine adjustment of the power supply, wire and speaker bracket of the equipment. After years of constant adjustment, some enthusiasts have found relatively satisfactory timbre and sound quality, which is one of the pleasures of "fever"

Many factors such as wires and listening environment also play a very important role in the sound quality of equipment. So you don't like what others think sounds good, and the combination recommended by others is not necessarily your ideal equipment. So before you decide to buy, I suggest you "do three more things":

One: Listen more-listen to some different brands of equipment and determine your favorite style;

Two: read more books-read more magazines about home appliances and stereos, and it is very helpful for you to know some common sense about stereos.

Three: Ask more questions-ask some old enthusiasts around or online, and tell your ideas for your reference, so that you can get a general market situation and avoid being cheated by merchants to a great extent, but other people's ideas can only be used as reference. Never blindly follow and buy a set of equipment that you don't recognize. The purchase of equipment must also depend on your own economic ability. Don't blindly pursue the grade of equipment and compare with each other. The equipment that suits you is the most worth buying. Whether you appreciate movies or music, you should be "people-oriented".

My experience in purchasing audio equipment and upgrading.

Personally, I think that to play stereo, we must first understand our infatuation and musical taste (music type, timbre characteristics). Most people like music and can listen to it actively and passively every day, but everyone likes music to a different degree, which determines how much you invest in buying a stereo. Many people like listening to music (especially pop music) very much before marriage or when they are young, but after marriage, with the increasing pressure of life (material and spiritual), the weakening of passion and the deepening of secularization, they are more busy with their children every day besides work, and it has become a luxury to sit down quietly and enjoy music. Audio is more of a decoration, which also determines the investment in buying audio when you get married and get married. If you firmly believe that you can keep your passion and personality and won't fall into secular life like ordinary people, then you can choose the ideal audio equipment in your mind; On the contrary, you will spend about 3000 yuan to buy a stereo with CD, MD or MP3, cassette, which is convenient and practical, does not disturb the people, and can be used as a toy for children in the future.

When buying a stereo, you must know your musical taste (music type, timbre characteristics). If you just like pop music, there is no need to spend too much money on audio equipment, because the characteristics of pop music (singer's voice, musical instruments and other factors) determine that its standards are relatively low, so the requirements for equipment playback are not high. If you like classical and jazz music, you should make great efforts to choose the audio equipment you need. Choosing audio equipment also follows the principle of value for money, but the timbre and characteristics of different brands of audio equipment are different, such as speed, power consumption, fineness and so on. This requires listening more and comparing more, and really understanding your own tastes. I've been playing stereo for more than ten years, and the biggest experience is not to expect it to be done in one step. Monophonic brick recorder in the late 1970s, Sharp)777； in the mid-1980s; In the early 1990 s, the pioneer landing suit and HIFI combined CD and soil cannon; Every upgrade makes me happy and gets me deeper and deeper. 1994 After listening to the crown sold by Dan in Beijing, I immediately knew where the gap was. On the eighth day of the Spring Festival in 1995 (opening on the first day after the festival), I took the crown of Dan in my heart and visited the Yifa Market in Panyu, Guangzhou for a whole day. As a result, I found a lot of equipment that fascinated me, but I couldn't start because of the budget. I lived in Longquan (next to Yifa) that night. The next day, after repeated comparison, I finally chose the Stduio 100+AQ wire rod of Gentleman Love Poetry +ProAc. Then I was immersed in the ocean of music. From this easy trip, I was fascinated by another thing-Hong Kong magazine Sound Technology, from which I learned a lot and gave me an objective understanding of my equipment: good analytical power, strong music flavor, but poor dynamics. With these understandings, I am not satisfied with the equipment I have now. I felt that the original choice was not professional enough and comprehensive enough, and I had the idea of upgrading. 1On New Year's Day in 997, I came to Yifa again. After nearly two years of study and research, I have learned a lot about acoustics and know what kind of music I need and what kind of sound I need. Or stay in Longquan. After the audition, I have two choices. ProAc's R 1sc and mighty bookshelves are top-notch. I am fascinated by the timbre of R 1sc, and I can't forget the delicate sound, especially the high frequency. The contrast between the new products of the two brands and the cooked "second-hand goods" is very obvious. What should I do? At this time, I listened to ProAc's R2.5 and R3.8, (I dare not listen to hundreds of thousands of R5. At that time, I thought I could never afford it. )

Because I like listening to strings best, and the timbre of ProAc is just to my taste. Its bright and transparent high frequency and high resolution are my favorite. R2.5 and R3.8 are calm, which R 1sc can't match. Of course, the price gap is huge. At this time, I saw a 5. 1 AC-3 cinema system (about 40 square meters) in the audition room. AV amplifier is the latest top AVSI merged by Tianlong (I can't remember clearly), and the DVD "The Last Assassin" is broadcast. At that time, the 5. 1AC-3 cinema system of DVD was a new product (I was still addicted to LD), which represented a direction. I decided to choose R 1sc first, and use it as a surround when upgrading later. As for the power amplifier, I chose the newly listed merged flagship PMAS 1 of Tianlong, which was impressive during the audition, with strong analytical ability, strong response and neutral voice. As for the CD player, I chose Tianlong's merged flagship S 1, balance line and coaxial line, speaker line or AQ in one step. In the words of my accompanying friends, I drove back a Li Xia (1997 price). From my return to1May 1998, I used this system to enjoy myself. Besides going to work, it's hard to listen to CDs and watch LD at home. Slightly insufficient: 1, the equipment takes up too much space. In order to give full play to the effect, I occupied a room (14 square meter). The CD player and amplifier are on the ground, the speaker is blocking the door, and the wall is tapestries and curtains (for listening effect). I often have to put up with my wife's nagging. 2. For dynamic works such as Sister Drum, Foreign Golden Horse and 18 12 Overture, the replay effect is worse than the ideal state.

This immortal day ended in May 1998, because work occupied my whole life, leaving at 8 o'clock in the morning and going home at 9 o'clock in the evening almost every day. Being busy has become a common practice, and it also keeps me away from TV, music, newspapers, books and periodicals. Looking back now, I don't understand how I lived at that time. 1May, 999, due to my job transfer, I finally got rid of my busyness and went back to my old fairy days, but when I heard the familiar music, my feeling changed. Perhaps a year of busyness (having a concrete understanding and deeper experience of society, interpersonal relationships and other aspects) has made my whole body and mind have changed a lot. I have a new understanding of the works I loved to listen to in the past, but the works I didn't often listen to in the past are now hidden. I attach great importance to the fullness and harmonious beauty of music works. During the period, due to the change of taste, the speaker cable was replaced by Swiss Ruibao, which slowed down the speed of the system and made the sound mellow and full.

In the winter of 2002, because I wanted to buy a new house and build an AV system, I decided to buy a box first, so I could listen to it directly when I moved, and then I went to Guangzhou. Because of the changes in the market, I easily changed careers. I amplified B& to Hai Yin and Guangzhou, and compared it, such as B&; Following W8 series, SONUS FABER famous piano series, DANI series, KEF series and so on, the new flagship floor box of ProAc was selected. There is nothing wrong with it, such as SONUS FABER's famous piano series, which is unforgettable when playing string works, and the box is simply a work of art and can be passed down from generation to generation. However, if you want to buy it, you need to wait for the instructions of the Italian manufacturer. After completion, the goods will be delivered from Hong Kong to Guangzhou, and the buyer will personally check and accept them. The box maker (school voice) is an Italian old man in his 80 s, and the time is uncertain. Except that you don't need to identify yourself, buying it is just like buying a Rolls Royce. It is a disaster to use it as the main channel of AV shooting. B& amp； W8 series needs heavyweight power amplifier, which is difficult to serve, but ProAc only needs high-quality power amplifier, not high power. In addition, I am used to the timbre of ProAc, so building AV requires the timbre of each channel to be consistent, and it can only be it. When I got home, nothing else changed. After listening to the new big guy, I finally got the expected ideal voice in my own home. The volume is adjusted to 10: 00, and the sound fills the whole room and the sound field; A description of the details; That kind of unhurried feeling; High overtone; Intermediate frequency density; The depth and intensity of low-frequency diving ... in short, the works that were not performed well before have been solved. What I heard and felt before were bookcases for small rooms. I never thought of using floor-standing boxes, but the actual effect was too different from what I expected. It's not a new house yet, the AV system hasn't been built, the center, the gun and the AV amplifier haven't been put in place yet, but the feeling of watching DVD is already great.

The above is my experience in purchasing equipment and upgrading. I want to help a friend who wants to buy audio equipment, and also reply to a friend who sent me a text message asking audio questions. Never! When playing stereo: 1, what you can't get is the best. 2, pursue one step at a time. 3,

Don't pay too much attention to advertising and market share.