Main technical indicators of speakers

The speaker market is full of mixed goods, with prices ranging from tens of yuan to thousands of yuan. How to choose a suitable speaker according to your application needs has become a problem that troubles many people. What kind of speaker is considered a truly good speaker? Especially for "novice" friends who don't know much about speakers, they can only look at the appearance and listen to the merchant playing a short piece of deafening music, and can only feel it with their senses; as for the technical indicators, they don't know where to start to judge the quality of the speaker. This article briefly introduces the relevant performance indicators of speakers, hoping that these contents can provide you with some reference when purchasing speakers.

Speaker technical indicators: sound technology
The more common hardware 3D sound technology now includes SRS, APX, Q-SOUND and Virtaul Dolby. Although they are implemented in different ways, they can all make people feel obvious three-dimensional effects, among which the first one is the most common. They all use the extended stereo theory, which is to process the sound signal through the circuit so that the listener feels that the sound direction is extended to the outside of the two speakers, so as to expand the sound, give people a sense of space and three-dimensionality, and produce a wider stereo effect. In addition, there are two sound enhancement technologies: active electromechanical servo technology and BBE high-definition high-altitude sound playback system technology, which also have a certain effect on improving sound quality.

Speaker technical indicators: frequency response range
The full name of the frequency response range is frequency range and frequency response. The former refers to the range between the lowest effective playback frequency and the highest effective playback frequency of the speaker system; the latter refers to the phenomenon that when an audio signal with a constant voltage output is connected to the system, the sound pressure generated by the speaker increases or decreases with the change of frequency, and the phase changes with the frequency. This change relationship between sound pressure and phase and frequency is called frequency response, and the unit is decibel (dB). The curves of sound pressure and phase lag changing with frequency are called "amplitude-frequency characteristics" and "phase-frequency characteristics" respectively, collectively known as "frequency characteristics". This is an important indicator for examining the performance of speakers. It has a direct relationship with the performance and price of the speakers. The smaller the decibel value, the flatter the frequency response curve of the speaker, the smaller the distortion, and the higher the performance. For example: the frequency response of a speaker is 60Hz~18kHz+/-3dB. These two concepts are sometimes not distinguished, and they are called frequency response. Theoretically, the harmonic components that make up the sound are very complex, and the wider the frequency range, the better the sound. However, this is still basically true for mid- and low-end multimedia speakers. Nowadays, speaker manufacturers generally mark the system frequency response range too large. The difference in the high frequency part is not much, but the marking at the bass end is extremely unrealistic. Therefore, we advise everyone to listen to the low-frequency sound with your own ears and do not easily believe the values ​​on the leaflets.

Speaker technical indicators: Sensitivity
This indicator refers to the sound pressure level measured one meter in front of the vertical center axis of the speaker plane when a 1W/1kHz signal is input to the speaker input end. The unit of sensitivity is decibel (dB). For every 3dB difference in the sensitivity of the speaker, the output sound pressure will double. The sensitivity of ordinary speakers is in the range of 85-90dB. Below 85dB is low sensitivity, and above 90dB is high sensitivity. Usually, the sensitivity of multimedia speakers is slightly lower.

Speaker technical indicators: power
The power label of the speaker is very confusing. Simply put, power refers to how powerful the sound emitted by the speaker can be. According to international standards, there are two ways to mark power: rated power and maximum withstand power (instantaneous power or peak power PMPO). The rated power refers to the maximum undistorted power that the speaker can emit when a continuous analog signal with a specified waveform is given to the speaker within the rated frequency range, and the maximum withstand power is the maximum electrical power that the speaker can emit without any damage. In order to cater to the psychology of consumers, merchants usually mark the music power very high, so when purchasing multimedia speakers, the rated power should be used as the standard. The maximum withstand power of the speaker is mainly determined by the chip power of the power amplifier, and it is also closely related to the power transformer. The weight difference between the main and auxiliary speakers can roughly know the weight of the transformer. Usually, the heavier the weight, the greater the power. However, the power of the speaker is not the greater the better, and the best is the applicable one. For an ordinary family user's room of about 20 square meters, a real 50W power is enough, and there is no need to pursue high power excessively.

Speaker Technical Indicators: Distortion
The definition of speaker distortion is basically the same as that of amplifier distortion. The difference is that the amplifier inputs an electrical signal and outputs an electrical signal, while the speaker inputs an electrical signal and outputs a sound wave signal. Therefore, the speaker distortion refers to the distortion of the electroacoustic signal conversion. The allowable range of sound wave distortion is within 10%, and the human ear is generally not sensitive to distortion within 5%. It is best not to buy speakers with a distortion greater than 5%.

Speaker technical indicators: signal-to-noise ratio
This indicator refers to the ratio of the normal sound signal played back by the speaker to the noise signal. If the signal-to-noise ratio is low, the noise is serious when a small signal is input, and the sound in the entire sound range becomes obviously turbid and unclear, and it is unclear what sound is being made, which seriously affects the sound quality. It is recommended not to buy speakers with a signal-to-noise ratio below 80dB (including subwoofers below 60dB).

Technical indicators of speakers: Impedance
This indicator refers to the ratio of the voltage to the current of the input signal. The input impedance of speakers is generally divided into high impedance and low impedance. Generally, those above 16 ohms are high impedance, and those below 8 ohms are low impedance. The standard impedance of speakers is 8 ohms. The nominal impedance of speakers on the market includes 4 ohms, 5 ohms, 6 ohms, 8 ohms, 16 ohms, etc. Although this indicator has nothing to do with the performance of the speaker, it is best not to buy low-impedance speakers. The recommended value is the standard 8 ohms. This is because when the power amplifier and output power are the same, low-impedance speakers can obtain greater output power, but too low impedance will cause underdamping and bass degradation.