Home theater speaker selection conditions

                                        Home theater speaker selection conditions

How to choose the right home theater speakers for beginners?

Can it ring?

Can plastic shell satellite speakers work?

How to avoid buying counterfeit goods?

What kind of speakers are qualified home theater speakers?

This is a question that many novice Xiaobai are quite confused. Recently, a friend left a message asking to talk about the selection criteria of home theater speakers. The following old snail will briefly talk about the key points of purchase. It is not necessarily correct, and it is for reference only.

1. Power

Many friends only focus on the power when purchasing speakers. It seems that the speakers with higher power will have better effect.

However, the meaning of power, to put it bluntly, is the maximum sound that can be produced. This parameter is very important for the design of stage sound reinforcement systems, but most household environments are at most 40 to 50 square meters, and the power of 100 or 200 watts is more than enough. Well, there's no need to worry about it.

THX certification has designed several certification standards for different room sizes, such as the common THX Select for small rooms, THX Ultra for medium-sized rooms, and THX Dominus for large rooms. Different room sizes have corresponding differences in power requirements. To put it bluntly, the larger the room The higher the power requirement, interested friends can go to THX official website to check.

This involves a problem of maximum sound pressure without distortion. Most home speakers have enough power, but power amplifiers often have problems such as false standards and insufficient power. We have talked about it before, so I won’t go into details here.

2. Sensitivity

Sensitivity is closely related to power parameters. The sensitivity of the speaker refers to the volume that the speaker can emit after inputting a signal with a certain power. Give the speaker a power of 1W, and test the sound pressure at a distance of 1m in front, so as to obtain the sensitivity value of the speaker.

To increase the sound pressure by 3dB, the power must be doubled. That is to say, the higher the sensitivity of the speaker, the louder it will be when driven by the same power.

Early home theater equipment was relatively cheap. In order to reduce costs and use low-end power amplifiers, the speakers were required to be as loud as possible. Correspondingly, the sensitivity of the speakers was increased, resulting in sound degradation. This is why HiFi speaker players look down on home theater players. one.

In addition, you will find that many stage speakers, karaoke speakers, and commercial speakers are basically very sensitive, just to achieve the same sound pressure level and lower equipment costs (high-power amplifiers are expensive).

The increase in sensitivity is at the expense of sound quality. The higher the sensitivity, the more distortion and noise you can hear. (Of course not absolute, this problem can be solved even if you are willing to spend money)

Therefore, many high-end HIFI speakers use low-sensitivity designs, such as many classic models of Dynaudio, but this virtually increases the requirements for front-end and power amplifier equipment. For home theater, there is nothing wrong with choosing a speaker with a sensitivity between 85-92dB/W/m.

3. Frequency bandwidth

I don’t know if you have seen the test frequency response curve in the picture above, especially when debugging a home theater. It can reflect the response of the speaker in each frequency band within the entire human hearing range (20-20kHz) ability.

If there is a large depression in a certain frequency band, it means that the reduction ability is poor, and the sound of this frequency will be weakened; on the contrary, if some frequency band has a large protrusion, the sound of this frequency will be strengthened. belongs to distortion.

When we buy home theater speakers, we need to pay attention to the sound reproduction range first, and then the flatness. According to the THX standard, the lower limit of the frequency response should not be lower than 80Hz (the frequency corresponding to the position of the steep slope in the figure above), and the lower limit of the frequency response of large floor-standing speakers can be lower, but in the home theater system, in order to reduce standing wave interference, we will cut it off .

As for the upper limit of the frequency response, it can reach about 20kHz.

4. Frequency response flatness

When we mentioned the frequency response curve above, we have to mention the flatness issue.

Home theater hi-fi speakers require that the flatness of the frequency response should meet the requirements of +/-4db (GB/T 7313-1987). Overall, this standard is loose, and the general industry default is +/-3db. No matter which standard it is, it is necessary to mark +/-, otherwise, its frequency response range is a matter of marking as much as you want.

In addition, not all speakers pursue a straight curve. Some audio manufacturers will have exclusive personalized tuning, similar to EQ processing, for example, to make the voice more full and mellow, highlighting the mid-range; some pursue elegant strings, There are those that enhance the treble; there are also those that enhance the bass in order to increase the thickness of the dialogue in the home theater. This is not good or bad, but the style is different. Just choose the one that suits you.

In general, in order to adapt to more different sound styles, the more flat and centered the better, which is the so-called "monitoring style".

The old snail here wants to remind you that the flatter the frequency response curve, the better the sound of the speaker. If the frequency response curve is good, the sound will not be bad; but if the frequency response is poor, the speaker will not sound very good.

5. Total harmonic distortion

There is another important parameter that affects the speaker's sound restoration effect, which is the degree of distortion.

This is also a very important parameter for the power amplifier. The harmonic distortion of the power amplifier is generally marked by the total harmonic distortion (THD) at 1000Hz, but because the harmonic distortion curve of the speaker fluctuates too much, it cannot be marked like this, generally it is Mark the total harmonic distortion value of the speaker in the whole frequency band.

Excellent speakers can reach the level of <1% in the range of 100-20000Hz. The general level is about 2% at 200Hz (the national standard GB/T 7313-1987 requires 200-1000Hz<2%), and the test condition is the standard 90dB sound pressure at 1 meter. But it is more difficult to meet this standard, so most manufacturers are embarrassed to mark it out, and some manufacturers will provide it, but the false mark phenomenon is very serious, so I can only say that it is for reference only.

6. Speaker size

Unlike stereo HiFi speakers, you can just buy a pair and put them on. A home theater is a surround sound system, which needs to be designed and planned in advance, pre-embedded, and decorated with acoustic treatments. It is a custom installation system.

Moreover, not only the sound of the speaker is required to be pleasant, but also the overall installation requirements must be met, which requires certain requirements for the size, installation method and appearance of the speaker.

For example, try not to use glossy speakers in the audio-visual room to avoid reflections; the living room environment should not be dull and thick, and needs to adapt to the home style and have a certain aesthetic design.

In particular, factors such as depth and thickness that may affect installation must be considered before purchasing.

Finally, the standards for high-quality speakers are far more than the above. Off-axis response will affect the actual listening performance. The product. Of course, you need to pay for certification, which involves cost-effectiveness. Another way is to refer to THX certification standards to purchase home theater speakers. Such speakers may not be very amazing, but they will definitely not be bad.