A microphone (also known as a microphone or microphone, the official Chinese name is a microphone), is a transducer that converts sound into electrical signals. Its working principle is that the vibration of the sound is transmitted to the diaphragm of the microphone, and the magnet inside is pushed to form a changing current, so that the changed current is sent to the subsequent sound processing circuit for amplification.
Recently I have received feedback from many fans that there will be echoes when using audio equipment to broadcast live or K songs. Everyone knows that the sound signal is collected by the microphone. So, today we will interpret the type of microphone and the pickup of the microphone. Case.
1. Microphone type
The sound-electric conversion principle is divided into: electric type (moving coil type, aluminum ribbon type), capacitive type (DC polarization type), piezoelectric type (crystal type, ceramic type), electromagnetic type, carbon particle type, semiconductor type, etc. Among them, dynamic microphones and condenser microphones are relatively common.
Condenser microphones send sound into the internal diaphragm and vibrate to cause the diaphragm to vibrate, causing the voltage to change and then generate a signal. Most of the diaphragms of condenser microphones are made of extremely thin materials, which have the characteristics of small size, light weight and high sensitivity; in terms of frequency response, the frequency response of the bass can extend to the ultra-low frequency below 10Hz, and the treble can easily reach the number. With the ultrasonic wave of 10KHz, the human ear's frequency response to sound is 20HZ-20KHZ. Therefore, after the sound recorded by the condenser microphone is amplified, we often hear some whistling or subtle sounds in our ears. The solution to this situation is to turn down the volume, and the other is to place the monitor farther away from the microphone.
The so-called moving coil microphone is made using the principle of electromagnetic induction. It uses a coil to cut magnetic lines of induction in a magnetic field. When the sound wave vibrates the diaphragm, it converts the sound signal into an electrical signal; its structure is relatively simple, Sensitivity and expanded high and low frequency response are weaker than condenser microphones, but they are also economical and durable. They can withstand very high sound pressure and are hardly affected by temperature or humidity. It contains softer sounds, suitable for recording vocals and live performances.
2. Microphone pickup
The pickup mode of a microphone refers to the sensitivity of the microphone to sounds from different directions or angles. In simple terms, it is the ability of the microphone to "hear" sounds from different directions. Common directivity categories are: omnidirectional, cardioid and super cardioid.
The front-end sensitivity of the cardioid microphone is strong, usually the side with LOGO on the front, and the back-end sensitivity is weak. In this way, the pickup direction can isolate unnecessary environmental noise, and the effect of eliminating echo is better than that of an omnidirectional microphone. Therefore, in terms of applicability, cardioid microphones are especially suitable for noisy stages.
Super heart shape
The pickup area of the super cardioid microphone is narrower than that of the cardioid microphone, which can eliminate the surrounding noise more effectively. But this kind of microphone also picks up sound at the back end, so the monitor speakers must be placed correctly. The super cardioid microphone is suitable for picking up a single sound source in a noisy environment and can effectively eliminate echo.
The omnidirectional microphone has the same sensitivity for all angles, which means it can pick up sound evenly from all directions. Therefore, the microphone does not have to point in a certain direction, which is particularly meaningful for lavalier microphones. The disadvantage of omnidirectional microphones is that they cannot avoid unnecessary sound sources, such as broadcast amplifiers, so there may be echoes.