How to determine the advantages and disadvantages of speakers from the technical and application poi

In the entire audio (including computer multimedia speakers) system, the speaker system as a sound reproduction tool, it is the most simple, but it is the most complex equipment. Because it is responsible for electro-acoustic conversion equipment, sound effects directly related to the quality of the entire system, so the speaker selection is appropriate, is to determine whether a sound system with the formation of an important factor in success. To determine the pros and cons of a pair of speakers, usually from the technical indicators and people's subjective listening to these two aspects.

A, Hi-Fi speakers of the main technical indicators

International Electrotechnical Commission (IEC) on home Hi-Fi speakers have developed a set of minimum standards, the standard file is encoded as IEC-581-7, as long as the speakers from the manual to see whether its technical parameters to achieve this one Minimum standards, can be more objective to determine whether the speaker qualified. IEC-581-7 for home Hi-Fi speakers some of the minimum standards are:

(1) frequency characteristics: in the 50Hz-12500Hz, the deviation in the +4 ~ 8dB; in the 100Hz ~ 8kHz frequency band, the deviation ≤ ± 4dB;

(2) Pointing characteristic: ± 30dB horizontal plane, ± 10dB vertical plane, the frequency response curve deviation compared with the positive axis ≤ ± 4dB;

(3) left and right channel speaker inconsistencies: 250Hz ~ 1kHz in the range of average sound pressure difference ≥ 2dB;

(4) The total harmonic distortion number: 250Hz ~ 1kHz, ≤ 2%, 1Hz ~ 2kHz, ≤ 1% -2%, 2kHz ~ 6.3kHz, ≤ 1%;

(5) impedance: 20Hz ~ 20kHz range, ≥ 80% of the rated impedance;

(6) to allow the use of power: ≥ 10W.

From the above criteria, we can easily see, meet the IEC Hi-Fi standard (high-fidelity) speaker technology is not very high, now available on the market by the regular manufacturer of the speaker can be basically meet or exceed these standards. So in this many qualified products, how to determine from the technical indicators up a pair of speakers is excellent? The speaker is the most important to see the frequency response range, point to the characteristics, sensitivity, power and impedance to bear these indicators.

Frequency response range refers to the range of speakers can replay the sound band, generally used Hz ~ kHz to represent. As the human ear on the audible frequency range is 20Hz ~ 20kHz, with age, the human ear hearing will drop to 25Hz ~ 16kHz or so. Therefore, as a pair of excellent speakers, the frequency response range of course, must meet or exceed this range.

The pointing characteristic shows the variation of the output sound pressure level when the loudspeaker deviates from the front axial direction, which has a great influence on the sound field width and positioning. But the speaker (mainly refers to the high-frequency unit) is not as wide as possible the better, professional products are certain requirements, well-designed unit (mainly trumpet) can be controlled in the specified range, and the sound pressure level is less than 6dB. General dome and cone units can not do, their directivity increases with the frequency gradually narrowed. To meet the characteristics of the requirements to meet the requirements of the unit is used: If the deviation from the positive direction of 30? O does not decrease compared to 4dB, then the crossover frequency f and the equivalent cone radius of a meet between f ≤ 140 / a, such as the diameter of 200mm (8 inches) speaker crossover point must be below 1650. Of course, some advanced design of the speaker unit can also set the crossover point higher than the theoretical value, but whether it is low, medium and high frequency speakers, in response to the choice of caliber, crossover point, the power to consider this point ( Two-way frequency is particularly important), many two-way speakers only in the frequency division into account the power capacity of the tweeter and the crossover point is high, ignoring the directivity requirements, such systems are often only in the front axle Has a good frequency response, while off-axis, the frequency response worse, affecting the sound field width and positioning.

Sensitivity refers to the efficiency of the speaker electro-acoustic conversion, usually with the sound pressure dB / W / m or dB (decibels) to represent, this indicator means the input power of 1 Watt speaker, 1 meter away from the speaker on the positive axis The size of the sound pressure obtained. Hi-Fi playback requirements of up to 110dB of output stage sound pressure, which requires the speaker must have a high sensitivity and a certain power margin, preferably greater than 88dB, so there are at least two benefits, first: the amplifier And speaker power capacity requirements, while reducing the cost of the two (88dB sensitivity of the output to reach 110dB SPL, to have 160W of input power, and sensitivity for each 3dB, 110dB SPL power required to drop one Times); second: can reduce distortion. Low Sensitivity To achieve the same sound pressure level as the high-sensitivity output, greater power and amplitude are required, but nonlinear distortion increases and the life of the speaker is reduced. Relatively speaking, better speaker sensitivity are more than 86dB, then they and the rated output power of only 50W with the amplifier will not be any problem, but not low sensitivity speakers are not good, like some classic Hi -End speakers, such as LS 3 / 5A and ATC SCM-20 and other sensitivity are lower than 85dB. Therefore, in terms of this indicator, of course, the bigger the better. Because the high sensitivity of the speakers in the input power of the same case, the obtained sound pressure will be lower than the sensitivity of the speaker, on the contrary, in the case of the same sound pressure, the amplifier power requirements than the low sensitivity of the speaker small. Therefore, the sensitivity is to evaluate a pair of speakers is easy to promote the important technical indicators.