7 Note: The speaker

1. Frequency Range
The full name is called frequency response range of the frequency range and frequency response. The former refers to the playback speaker system the lowest effective frequency and the maximum effective range of between playback frequency; the latter refers to a constant voltage output of the audio signal when connected to the system, speaker sound pressure generated by the change in frequency of occurrence with increase or attenuation, phase change with frequency and the phenomenon of sound pressure and phase associated with the frequency of changes in the relationship is called the frequency response, the unit decibels (dB). Sound pressure and phase lag with frequency of curves is called "amplitude-frequency characteristics" and the "phase-frequency characteristics", collectively, the "frequency characteristics." This is to examine the pros and cons of speaker performance, an important indicator of its performance and price with the speaker has a direct relationship, its decibel value the smaller the speaker's frequency response curve shows the more flat, distortion, the smaller the higher the performance.

2. Sensitivity
This indicator refers to the speaker input 1W/1kHz input signals, horn speaker away from central axis perpendicular to the plane of the places in front of one meter measured the sound pressure level. The unit of sensitivity decibels (dB). The sensitivity of each speaker difference 3dB, output sound pressure on the difference of twice the sensitivity of normal speakers in the 85 ~ 90dB within, 85dB below the low sensitivity, 90dB high sensitivity of the above.

3. Power
According to international standards, the power, there are two annotation methods: rated power and maximum tolerance power (instantaneous power or peak power PMPO). The power rating refers to the rated frequency range to the speaker provides a continuous analog waveform signal, speaker can not issue the maximum distortion power, and the greatest power is the speaker does not bear any damage to the maximum electric power. Boxes bear the greatest power of the main power of the decision by the power amplifier chip, in addition to a great relationship was kind enough to power transformer. But the speaker's power is not the bigger the better, for that is the best.

4. Distortion
Speaker distortion of the definition of the distortion amplifier is basically the same, only difference is that the signal amplifier input, output or signal, while the speaker is the input signal, the output is the acoustic signal. Therefore, distortion of the speaker refers to the distortion of electro-acoustic signal conversion. Acoustic distortion within the allowed range is 10%, most people's ears the distortion of 5% or below is not sensitive. Distortion is best not to buy more than 5% of the speakers.

5. SNR
This indicator refers to the normal playback speaker sound signal and noise signal ratio. Signal to noise ratio is low, small-signal input of serious noise pollution in the whole range of voices become markedly turbid, I do not know what is issued by sound, seriously affect the sound quality. Less than 80dB signal to noise ratio of the speaker (including subwoofer less than 60dB) suggested not to buy.

6. Impedance
This indicator refers to the input signal voltage and current ratio. Speaker's input impedance is generally divided into two types of high impedance and low impedance, generally higher than the 16-ohm high-impedance, less than 8 ohm low-impedance, speaker impedance is 8 ohms standard. Market, the nominal speaker impedance 4 ohms, 5 ohms, 6 ohms, 8 ohms, 16 ohms and so few, although the performance of this indicator has nothing to do with the speaker, but it is best not to buy low-impedance speakers, recommended value is the standard 8 ohms, this is because the power amplifier and the output power of the same circumstances, the low impedance of the speaker can get a larger output power, but the impedance is too low will result in less degradation phenomena such as damping and bass.

7. Sound Technology
Hardware 3D audio technology is now more common SRS, APX, Q-SOUND and several other Virtaul Dolby, with their own methods to achieve different, but people could feel the obvious three-dimensional effect, Among them, the first one of the most common. Applications are expanding their stereo (Extended Stereo) theory, which is the sound signal through the circuit for additional processing, the listener feel that the sound position extended to the two speakers on the outside so as to carry out sound expansion, it gives people a sense of space and three-dimensional feeling, resulting in a more spacious stereo effect. In addition, there are two kinds of sound-enhancement technology: active electromechanical servo technology, and BBE high-definition audio playback system technology plateau, to improve the sound quality is also a certain effect