Microphone and microphone knowledge

- Jan 02, 2020-

he recorder's understanding of the recording microphone should be the same as that of the soldier's gun. Next, we will start with the structure of recording microphone and analyze the principle and characteristics of microphone.

Directivity of recording microphone

All microphones have a place to receive the sound signal. Here we call it the sound head. The general position is behind the diaphragm. There are three structures of the head. One is single-sided pressure acceptance type, with only one end open, so that only one side of the diaphragm can accept the sound pressure. The other is the pressure angle acceptance? Full open type, that is, both sides of the diaphragm can accept sound from various angles. *One kind of pressure angle acceptance? Semi open type is that both sides of the diaphragm can only receive sound waves in a specific direction. The specific principle will be explained in detail later.

There is only one diaphragm that can accept the sound pressure, and the sound wave on the back will come around the front, so it can also be sensed, so that the sound in any direction can be picked up, so we call this directivity omnidirectional, which is usually called Omni in English, or a circle pattern instead.

Both sides can accept the shock film of various sounds, and the sound waves from both sides can circle to the front and the back respectively, so as to generate the same pressure, so as to cancel out. As a result, it becomes the shape of the eight character, which is often referred to as the eight character direction.

There is also a case in which the sound wave from the opposite side is allowed to pass through the diaphragm, so as to cancel out the sound wave from the front side. Therefore, the sound from the back cannot be picked up. This is the microphone with the heart-shaped direction. Generally, a heart pattern is used instead.

At this time, someone yelled, just these three directions, right? How can I see that there are seven directions? How does that come out? There are some microphones with these directions, and how does that work? The answer to this question seems very simple, that is, head changing or the superposition of directions. It's very simple to change the head. Screw off the original head and replace it with a suitable one. Blue's large diaphragm microphone prefers this technology, so it's often seen. Stacking is to stack two kinds of directional heads to become a new direction, for example, a heart-shaped point plus an 8-word point is the full direction. Many large diaphragm microphones with options are realized by this method.

The head not only determines the direction, but also the characteristics of the timbre. The single-sided pressure receiving head can pick up and take out the natural and clear sound, with excellent sense of depth and reality, and good low frequency control. The pressure angle receptive head will have close talk effect. If it is used properly, it is a very excellent low-frequency EQ, which can control the frequency response very naturally, but if it is not used well, the effect will be very bad.

Recording microphone, headset and speaker

When you see this title, you will ask, is there any relationship between the three? Microphone is recording, while headphones and speakers are playing back sound, which seems to be the opposite, totally irrelevant. But if we carefully analyze their principles, we will find similarities. Earphones and speakers convert digital signals into vibration of diaphragm and make sound, while microphones convert vibration of diaphragm into digital signals. The difference between the two is just the opposite of the signal flow, which shows that the characteristics of the two will be partially repeated. After talking about the relationship among the three, the main purpose is to make a comparison with headphones or speakers in the future, so as to have a deeper understanding of certain characteristics


Condenser microphone can be divided into large diaphragm and small diaphragm according to the size of diaphragm. This is the beginning of the struggle between the big and the small diaphragm. Generally speaking, the larger the diameter of the diaphragm is, the smaller it is. But it's not a dead rule. For example, what is a 0.9999-inch-diameter diaphragm called? It should be considered a large diaphragm.The characteristics of the large diaphragm (as shown in Fig. 2 ac-audio ec2000b microphone) are very similar to those of the loudspeaker. As we all know, the caliber of woofer is generally very large, while that of tweeter is relatively small. This is because when the high-frequency sound wave reaches the surface of the diaphragm, the diaphragm will generate corresponding high-frequency motion. If the materials of the diaphragm are not uniform, the mechanical properties will not be the same. At this time, there will be several different vibration conditions of the diaphragm, resulting in the deformation of the diaphragm. In this way, distortion is inevitable. However, due to the relatively small size of the small diaphragm, the chance of uneven material is much smaller than that of the large diaphragm, and the strength of the whole diaphragm is not easy to deform, so the high-frequency distortion will be relatively small. In the same way, the performance of large diaphragm for high frequency will not be as good as that of small diaphragm, because the upper limit of diaphragm frequency is limited. And the small diaphragm, for high frequency performance, and low frequency is not good, because the lower limit of the small diaphragm frequency is limited. In this way, different sound characteristics of large shock film and small shock film are also cast.

The timbre of the big shock film is usually warm and broad. It feels very good in the middle and low frequency. It's very real! The resolution of the small shock film is very amazing and delicate in the high frequency. In this way, the overall timbre is colder. Therefore, the choice of timbre becomes very important.

What is a tube microphone

The condenser microphone is converted into a signal after the voice head, and then there is an amplifier part, which needs to increase the voltage and reduce the resistance of the signal. This amplifier can be transistor or electron tube. Because transistor life is cheap, enthusiasts look down on it, and professionals don't care, so there is no transistor microphone. And the electronic tube, which has a good life, can be called the electronic tube microphone independently, and can fool the public to think that it does not belong to the condenser microphone. Electronic tube microphone, which is often called tube microphone. But actually, you need to understand that the tube microphone is actually a condenser microphone