Interpretation and application of speaker technical indicators

The following is an example of the French Jinlang 907Be bookcase:

1. Withstand power: 90W
2. Frequency response: 50-37KHZ-3dB
3. Weighing impedance: 8 Euro
4. Sensitivity: 89dB
5. Net weight: 12kg
6. Volume: H × W × D 420 × 231 × 348

â‘  Withstand power of 90W, the non-linear distortion of the talk box does not exceed the specified value (generally 1 to 5%), the average power that can be continuously fed in, also known as the rated power, it is a dynamic index. In actual use, try not to work for more than 90W for a long time, but short time is allowed, and it is also inevitable, because the audio signal contains a large number of quenching signals. In particular, some CD test discs are extremely dynamic in an instant, often exceeding N times the normal signal. Many early buddies, using <Ajiegu> to test the low frequency, often turn the volume of the amplifier to close to or exceed 12 o'clock, which often causes the phenomenon of bottoming, edge beat, and even burns the speaker. Pay special attention, especially for imported bookshelves Boxes, they are generally not very overloaded. (Mainly due to commercial considerations, the greater the withstand power, the higher the relative price). The domestic production is relatively better. Due to the continuation of the long-term influence of the planned economy and the more honest attitude of the Chinese, the remaining power margin is larger. Such as "Fei Le ... Southern Whale, etc.". But don't be afraid, the speakers will come for use, not for reading. There is no problem with 2 times the rated power in a short time, up to 4 times (very short time).

Generally, you can usually enjoy music volume control at 3-10W. What is the concept of 10W? You can use a multimeter to measure the red and black ends of the power amplifier output, and the AC swing to 9-10V (referring to 8 ohm speakers). The power is about 10W. The calculation method: the square of the AC voltage (V) divided by the speaker impedance (ohm) is equal to the power (W). At this time, the loudness can already feel the shock of low frequency.

â‘¡Frequency response: (50-37KH2-3dB), also known as effective frequency range, refers to adding a constant signal to the speaker. The characteristic curve of the sound pressure radiated from low frequency to high frequency varies with frequency. The International Electrotechnical Commission (IEC) stipulates that the average sound pressure level is reduced by 10dB as the effective frequency range of the speaker. It seems that this standard is too low. The manufacturer's standard is much higher than this standard.

If you do n’t specify the negative dB in the frequency response of the speaker, the frequency response index is meaningless. The wave marked by Jinlang is clearly -3dB, reflecting that the box has a very flat frequency response curve. In other words, its playback sound quality must be good. Conversely, some imported boxes can also be standard -6dB, low-end cargo standard -10dB, and some simply do not deliberately come to the fans. The frequency response marked by the same speaker will be different due to the different decibel value.
Such as Jinlang box: 50-37KHZ-3dB
Can also be marked: 45-40KHZ-6dB
Even worse standard: 38-42KHZ-10dB
Not standard at all: 32-37KHZ

Therefore, looking at the frequency response index, you must pay attention to the decibel value to have a reference value (the front 50HZ number represents the lower the bass frequency, the better, and the back 37KHZ represents the high frequency, the higher the better. This Jinlang 907Be speaker has strict standards, The index is quite high and the performance is definitely good.

â‘¢ Impedance is 8 ohms, the actual impedance of the speaker has a characteristic that changes with frequency, and is called the characteristic of the speaker impedance. It shows the maximum value at the low-frequency resonance frequency f0. After the resonance frequency f0 is gradually increased, the impedance will have a minimum value. The impedance at this time is called the rated impedance. This sentence may be difficult to understand. It is said that the common point is the correspondence at the corner of the low-frequency resonance frequency rise. The impedance is the rated impedance. It is generally 1.05-1.1 times the DC impedance of the voice coil, such as 8 ohm rated impedance, the measured DC resistance of the voice coil is about 7.2. How much impedance does not affect the sound quality, just as a reference value for the power amplifier. Generally, home speakers are between 4-16 Euros, and it is better to choose 8 Euros, especially as a mid-range speaker. It will be easier to match when upgrading the main box in the future, because AV amplifiers are not recommended to use speakers lower than 4 Euros.

â‘£ The sensitivity is 89dB, which is a quantified index indicating the efficiency of the loudspeaker's electric-to-sound transduction, usually expressed in decibels. The characteristic sensitivity is the sound pressure level measured at the IM from the speaker axis (measured in the anechoic room) when the IW pink noise electric power is input to the speaker.

The level of sensitivity index has certain significance to the optional power amplifier. Due to the customary definition in the industry: every 3dB difference, the loudness will be doubled. That is to say, when the same power is fed to the speaker, such as a 90dB speaker, it will be twice as loud as the 87dB speaker. , And so on, 93dB is 2 times larger ...

Most common home speakers on the market are between 84-94dB, I divided them into three levels:

â‘  Low sensitivity, 84-86dB
â‘ Medium sensitivity, 87-89dB
â‘ High sensitivity, above 90dB

When choosing speakers, choose medium and high sensitivity (above 87dB) especially when playing AV. Generally, the output power of AV amplifiers is limited. On the contrary, it must be equipped with a high-power AV amplifier, otherwise it will promote low-sensitivity speaker pairs (such as Dynaudio, AAD, etc.). In order to obtain certain sound effects, it is necessary to artificially increase the output of the AV amplifier, which is unfavorable for the amplifier. Of course, if you really play Hi-Fi, it is another matter.

⑤ The net weight is 12kg. It is easy to understand. The heavier the speaker is, the better the box is. It is good for eliminating resonance phenomenon. The international standard weight unit is kg, which is commonly used in China.

â‘¥ Volume is generally measured in millimeters or centimeters. There are already internationally in inches, 1 inch = 2.54 centimeters, you just need to convert it. H stands for high, W stands for wide, and D stands for deep.

⑦ Another speaker also has an important distortion index, which is generally unwilling to be marked by manufacturers. The degree of distortion includes harmonic distortion, intermodulation distortion, phase distortion, etc., and the percentage is commonly used to indicate the degree of distortion. The distortion of the speaker is generally 2-5%, and the imported models with better brand names can be controlled at about 1%. The reason why manufacturers are reluctant to mark it is that compared with other audio equipment, such as power amplifiers, CD players, etc., the distortion is From a few ten thousandths to a few hundred thousandths, only a few percent of speakers are too shameful. Why do we often say that speakers are the weakest link in audio equipment, mainly referring to its distortion. In the process of electroacoustic conversion, it is difficult to eliminate some mechanical, geometric, electromagnetic and other aspects. Therefore, the manufacturer simply does not mark this index. var check_allow = "/d/Api/iscantalk.html"; var add_url = '/ d / article / write /'; function CheckLogin () {now_uid = ''; var ElecfansApi_checklogin = '/ webapi / passport / checklogin'; var logout_url = "{: U ('Login / logout')}"; var logout_url = 'http://bbs.elecfans.com/member.php?mod=logging&action=logout&refer=front'; $ .get (ElecfansApi_checklogin, function (data, textStatus) {if (data! = "") {EchoLoginInfo (data); CheckEmailInfo (data); data = $ .parseJSON (data); now_uid = data.uid; / * var login_content = 'write an article