Understand that the public address system is no longer a problem

How to quickly understand the public broadcasting system? This article provides you with high-quality knowledge, which can be divided into five major blocks, power, sensitivity, distortion, frequency range, and frequency response.

1. Power:

Power is divided into nominal power and maximum withstand power. Nominal power is the rated power we often say. It determines the state under which the speaker can work stably for a long time.

Take the NW-20 speaker as an example, its nominal power is 20W, which means that it can work for a long time and stable power is 20W, if the speaker is often operated in a state higher than 20W, it will be very easy to damage. The maximum withstand power refers to the maximum power that the speaker can withstand in a short time. Generally 3-4 times the nominal power.

To give a simple example, when a film reaches the climax, it often uses shocking music effects to render the atmosphere at that time. At this time, the sound intensity of the speaker will basically exceed the nominal power of the speaker. There is a limit to the value. This limit is the maximum power that the speaker can withstand.

From the above, we can easily see that there is no direct relationship between the power and the sound quality of the speaker. It determines the maximum sound intensity that the speaker can emit.

2. Sensitivity:

Sensitivity is an indicator to measure the efficiency of the speaker, it has nothing to do with the sound quality of the speaker. The sensitivity of ordinary speakers is generally between 85-90dB (decibel), and high-end speakers are above 100dB.

The increase in sensitivity comes at the cost of increased distortion, so as a high-fidelity speaker, it is necessary to reduce some of the sensitivity requirements to ensure the restoration and reproduction of sound.

Therefore, we can't think that the sound quality of speakers with high sensitivity must be bad, while those with low sensitivity must be good.

3. Distortion:

Distortion can be divided into three types: harmonic distortion, intermodulation distortion and transient distortion. The distortion we usually call is harmonic distortion, which refers to the distortion caused by the addition of higher harmonic components that the original signal does not have during the sound playback.

What really affects the quality of the speaker is the transient distortion. The transient distortion is because the speaker has a certain amount of inertial mass. The vibration of the basin cannot keep up with the vibration of the electrical signal that changes momentarily. Difference. This concept is not easy to understand, we just need to remember that the distortion of ordinary multimedia speakers should be less than 0.5%, and the distortion of the subwoofer should be less than 5%.

4. Frequency range:

Frequency range refers to the distortion between the lowest effective playback frequency and the highest effective playback frequency, which can be divided into three types: harmonic distortion, intermodulation distortion and transient distortion. The distortion we usually call is harmonic distortion, which refers to the distortion caused by the addition of higher harmonic components that the original signal does not have during the sound playback.

What really affects the quality of the speaker is the transient distortion. The transient distortion is because the speaker has a certain inertial mass. The vibration of the basin cannot keep up with the vibration of the instantaneously changing electrical signal. Difference.

This concept is not easy to understand, we just need to remember that the distortion of ordinary multimedia speakers should be less than 0.5%, and the distortion of the subwoofer should be less than 5%. Scope.

In general, the audio signal that people can hear is about 20Hz ~ 20kHz with different frequencies, different waveforms, and different amplitudes. Therefore, the amplifier must have a wide enough work to amplify the audio signal frequency band.

We call an amplifier at a specified power, and the frequency bandwidth between the two points when the gain at the high and low ends of the frequency drops by 0.707 times is called the frequency response range of the amplifier. The frequency response range of relatively good amplifiers is generally between 18Hz-20kHz.

5. Frequency response:

Frequency response refers to the phenomenon that when an audio signal output at a constant voltage is connected to the speaker 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 in the relationship between sound pressure and phase and frequency is called the frequency response. It has a direct relationship with the performance and price of the speaker. The smaller the value, the flatter the frequency response curve, the smaller the distortion, and the higher the performance.