How to buy the center speaker in the audio-visual room

Audio-visual room speakers are also called AV speakers. They are both different and related to HiFi speakers. Both AV speakers and HiFi speakers should meet the minimum performance requirements of high-fidelity speakers. Speakers are equipment with a strong subjective evaluation, so it is difficult for ordinary consumers to grasp when purchasing. The shopping tips provided in this article focus on practicality and maneuverability, hoping to enhance consumers' immunity to poor equipment.

1. Pay attention to the difference in the material of the speaker diaphragm
For audio-visual room speakers, there are various forms, including main speakers, center speakers, and surround speakers. First of all, the sound of each channel speaker is required to be unified. Tone is a comprehensive reflection of the characteristics of speakers, and it is more difficult for ordinary consumers to effectively grasp it. Generally speaking, the material of the speaker diaphragm is different, which has a more obvious impact on the tone.
The materials of the cone diaphragm mainly include ordinary paper cones, woolen cones, paper cones sprayed with resin on the surface, PP cones, carbon fiber woven cones and glass fiber cones. Ordinary paper cones are widely used and low in price, and their tone is basically neutral. The defect is that the middle and high ranges of the frequency response are not easy to handle when dividing the frequency, and there are limitations in appearance. The sound of the paper cone mixed with wool is mellow and gives a sense of warmth. The surface of the paper cone sprayed with resin material has an improved appearance, and the sound performance tends to be slender. The inner damping of the fiber woven basin is large, the response is flat, and it is easy to make crossover connections, but the price is more expensive, and the bass processing is not good, and there will be a hard subjective hearing experience. The medium and high frequency broadcast of the PP basin is better, and the sense of hierarchy is strong, but its use as a bass in the audio-visual room is limited.
Dome-shaped diaphragms are generally used for mid- to high-frequency speakers. The materials include hard dome such as aluminum alloy and titanium alloy, and soft dome such as silk film, cloth film and nylon film. The hard dome has a wide frequency response, strong sound penetration, and a good sense of hierarchy. The soft dome has a flat frequency response and a soft tone. Hard dome speakers are generally good at reproducing analog sound sources, and soft dome speakers are generally good at reproducing digital sound sources. This is just a relative concept, and a conclusion cannot be drawn from this: the hard dome speaker is a low-end configuration, and the soft dome speaker is a high-end configuration. If this is true, wouldn't JBL, which uses a large number of titanium films, only produce low-end products? In fact, hard dome speakers are most suitable for three-way speakers, while soft dome speakers are much easier. On the other hand, the price of soft dome speakers is relatively low, usually only 1/3 to 1/2 of hard dome speakers, so soft dome speakers are mostly used in commercial speakers. However, in the audio-visual room, because the sound dynamics are relatively large, and the dynamics of the soft dome speaker is relatively small, the sound is prone to hairy under high power. This should be paid special attention to when buying.
Consumers have a general understanding of the timbre of speakers. When buying, they can decide which speakers to use according to their preferences. If they feel unsure, it is best to make the speaker diaphragm materials of several speakers in the audio-visual room consistent.

2. Pay attention to the difference between double bass speakers and passive radiating speakers
Double woofer refers to the use of two woofers with the same caliber in one speaker. The double woofer has higher low-frequency radiation efficiency and good horizontal directivity, which is more suitable for use in audio-visual rooms. The passive radiating speaker is a woofer plus a passive radiator. The two are very similar in appearance. Under the same specifications, the cost, price and power of the double woofer are greater than those of the passive radiating speaker. Speakers. The identification method of the two is as follows. When playing the sound, press the two bass vibrating units separately, and the sound of both becomes smaller and there is no obvious difference, and it should be a double bass speaker. If one bass vibrating unit is pressed, the sound becomes smaller, and the mid-frequency sound of pressing the other bass vibrating unit does not change, but the bass effect is weakened, and the latter is a passive body.

Third, the purchase skills of the center speaker
The form of the center speaker is relatively fixed. The center speaker usually uses two 4-inch or 5-inch units, or adds a dome tweeter based on this. Its main function is to make the dialogue clear and stabilize the sound image. At the same time, when the sound image is moving Ensure its continuity and smoothness. The front of some center speakers is designed to have a certain angle with the bottom. If the center speaker is placed high or low, it is more appropriate to use this type of center speaker, which is more convenient for the axial radiation of the speaker to be aimed at the audience.
In the normal mode of Dolby Pro Logic, the requirements for center speakers are lower, and most of the commercially available center speakers are of this type. In the Dolby Pro Logic Broadband Mode and AC-3 system, the requirements for the center channel are higher, requiring flat response, low distortion and large dynamics. The center speaker should preferably be a speaker consistent with the main channel, at least The index should also be close to the main channel.

Among the indicators of most commercially available center speakers, the lower limit of the frequency response is about 80-100Hz, the sensitivity is about 86dB, and the power endurance is 20-40W. This type of center speaker is not suitable for broadband mode and AC-3 systems. Many center speakers on the market use ordinary low-power speakers, which have large frequency response unevenness and large distortion. In the wideband mode, human dialogues are changed and distorted, and there is a feeling of hoarseness. The sound image is also erratic. If the objects on the screen move from left to right, the movement of the sound image makes people feel awkward and unnatural. In addition, in order to make the sound feel loud, the impedance of some center speakers is even lower than 4Ω, which can easily damage the amplifier. Therefore, you must be careful when choosing a center speaker. In the actual audition, if you feel that the sound is very noisy, the problem is most likely to be on the center speaker. You can put the AV amplifier in phantom mode and the effect becomes better, you can verify this conclusion.

Fourth, the purchase skills of surround speakers
The function of the surround speakers is to increase the surround presence of the sound field, and to ensure the continuity and smoothness of the transition when the sound image moves back and forth. Surround speakers are generally small in size. It emphasizes a sense of sound field diffusion, requiring speakers to have a wide directivity, or a flat power response. Many surround speakers on the market have similar problems with center speakers, so you should also pay attention to them when buying. Home THX surround speakers require the use of bipolar speakers. This type of speaker has two radiation directions with an angle of 90°～180°. The radiation direction does not point to the audience, but uses the reflection of the wall to create a good diffuse sound field.
The surround channel of Dolby Pro Logic has a frequency response range of 100Hz to 7kHz, while the AC-3 surround channel is a full frequency band. Therefore, the purchase of surround speakers is best to use wide-band speakers for future upgrades.

5. Sensory selection skills
When buying a speaker, you need to be able to see it with your eyes, hands, and ears.
See it: you need to see whether there are any defects in the appearance of the speaker, whether the surface decoration skin is obvious at the edges and corners, and whether there is blistering or unevenness on the surface. Pay attention to distinguish the difference between the dura dome tweeter and the plastic diaphragm tweeter with a metal layer on the surface. The domestic plastic diaphragm has poor treble performance, strong sound burr, and is not resistant to hearing. There is usually no convexity on the diaphragm of this type of treble. Out of the strong pattern.
Hand arrives: Take a look at the weight of the speaker. Usually the cabinet is heavy, indicating that the speaker cabinet material is thicker or the speaker uses a larger magnetic circuit. Some speaker speakers look large in diameter, but the magnetic circuit is small. The speakers sounded muddy bass, low voice, prominent and harsh treble, and relatively light weight. In addition, some manufacturers have added a thicker (some up to 20mm thick) wooden frame to the back or front of the speaker, and a PVC decorative film is pasted on the outside, giving the illusion that the board is very thick (the actual board thickness may be very thin) ), the weight of this kind of speakers is generally lighter, as long as it is compared with the famous brand speakers of the same specification. On the woofer, spread your five fingers evenly on the cone of the paper cone. Press a few times to check the softness. Softness indicates that the field sounder has a low fO and may have a better low-frequency response. Press the fold ring (mostly rubber edge) on the outermost ring of the speaker again and loosen it quickly. The inferior fold ring has a "pop" sound. The speaker fold ring is also made of polyurethane foam, the bass effect is softer than the rubber fold ring, and the sensitivity is higher. The surface of the foam fold ring is rougher than the rubber fold ring, and the service life is lower than that of the rubber fold ring. The woofer with cloth-impregnated rubber folding ring has higher sensitivity, but the distortion is relatively large, especially the domestic cloth-impregnated rubber folding ring speaker.
The above-mentioned judgment methods are only simple judgments and cannot be absolute. It’s better to hear it, and to verify it by actually listening to it. It would be beneficial to use brand-name products as a comparative reference.

Sixth, find the reference configuration
As with the choice of AV amplifiers, it is a very effective way to select representative products for reference. The representative audio-visual room speakers currently on the market are: Yamaha NS-30X, NS-5X, NS-10M and NS-70 (main speakers above), NS-P50 (surround and center), Dushi 5.1a (Full set), Dushi 3.1 (full set), Coats FB series (full set), C-LV series (full set), Panasonic THX series audio-visual room speakers (full set), JBLMR series, Dr. AM10 (satellite type), Muse AV- 2 series, MB+BC series of the small whirlwind, etc.

Seven, the inspection of the magnetic shielding of the speaker
In the case of limited living room conditions, the main speakers and center speakers are very close to the TV. When the stray magnetic field on the surface of the picture tube exceeds 1 Gauss, the color or pattern of the image will be changed and distorted. Therefore, magnetic shielding is very important. The magnetic steel produced by the external magnetic speaker is very strong, so the speaker must Magnetically shielded speakers are used. To meet the same performance requirements, the price of magnetically shielded speakers is higher than that of non-magnetically shielded speakers. Some manufacturers still use external magnetic speakers or speakers with poor magnetic shielding in order to reduce costs, so magnetic shielding must be checked. During the test, the speaker and the TV can be placed close together, and the TV status can be set to the no signal blue screen state. After a period of time (some speakers can not see obvious effects in a short period of time, ordinary people can't see the obvious effect. After about ten minutes The impact will only appear. So don’t think that you can examine the magnetic shielding effect of the speaker by leaning the speaker against the TV. If the color (especially on the four corners of the TV tube) does not change, then the magnetic shielding meets the requirements, otherwise There may be no magnetic shielding or the magnetic shielding cannot meet the requirements. The magnetic shielding requirements of the center speaker are relatively high, and the requirements of the main speaker can be appropriately reduced, so the main speaker can also be placed in a place slightly far away from the TV set allowed by the sound field for testing.

8. Beware of counterfeiting when buying imported speakers
There are many irregularities in the domestic speaker market. Some manufacturers take advantage of consumers' superstition of imported speakers to make tricks. For example, domestic manufacturers have registered trademarks abroad, produced domestically, and then entered the market after fake exports, or completely faked famous brands, and produced and sold them in a stately manner. The speakers used in this type of speakers are mostly made up of domestic parts, which are rough in appearance and obviously distorted in middle and high frequencies. And the portion is too much. There is an identification method for consumers to refer to. Usually, the outside of the folding ring of the woofer speaker will be marked with the model number. The domestically produced part is not marked or the size is larger than the imported part. For example, the imported part of the 6.5-inch speaker will be marked with the words EC-141, etc. The speakers are mostly 158, 160, etc. The imported 8-inch speakers will be marked with the words EC-178, and the domestic speakers are mostly 200. Therefore, you should choose an agency with a higher reputation to buy imported products. If you find any difference, you should ask someone who is knowledgeable to help you identify it, and beware of being deceived.
Through such a detailed explanation, I believe that everyone must have their own understanding of how to buy audio-visual room speakers, and combined with the actual situation of your home, you should know what kind of speakers you want to buy.
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