Shotgun Microphone

I. What is a shotgun microphone?
In some large video recording sites, it is often seen that some workers will hold or install a long gun-shaped object on the shelf to pick up the sound by aiming at the sound source, which is the shotgun microphone.

Shotgun microphones first appeared in the 1960s. At that time, home TV had begun to be popular in Europe and the United States, and the demand for film and television production and news interviews was also increasing, and professional production equipment and recording equipment had become the market demand.

In 1961, the world's first shotgun microphone was developed by Electro-Voic Company of the United States, which can be said to be a milestone in outdoor recording equipment.

With the fame of the shotgun microphone, the shotgun microphone has gradually become an indispensable "equipment" in the film and television media industry. Therefore, more and more microphone brands have joined the research and development team of gun-type microphones, and the performance, configuration and sound quality of gun-type microphones are gradually improving.

In the early days, the shotgun microphone was only popular in professional fields such as news media, but not in the civilian field. With the rapid development of the Internet, especially the rapid development of online social networking and video self-media creation, the production of Vlog is becoming more and more popular, and the shotgun microphone has become one of the preferred recording devices for Vlogger.

II. How Shotgun Microphones Work:
In fact, the working principle of the shotgun microphone is not complicated. It is mainly designed through the pressure gradient principle of the microphone. The sound reaches the microphone diaphragm through the on-axis pipeline. The pressure sensor generates an audio circuit by recording the vibration of the diaphragm, thus picking up the strength of the audio signal.

Shotgun microphones are mostly "interference tubes" (also known as sound collection tubes) with long slots, which are dense inside the tube wall, covered with a protective net on the top, and slotted slots on the side of the protective net.

As the sound passes over the shaft, it reaches the microphone diaphragm unimpeded. When the off-axis noise enters from multiple notches, it will be attenuated due to the arrival of different phases, thus reducing the pickup of external noise.

Shotgun microphones are more directional than other types of microphones. It has two main pickup modes: cardioid pointing and supercardioid pointing. Compared with other directional microphones, the core is more compact and compact.

III. How is a shotgun microphone different from a lavalier microphone?
① Appearance
The most obvious is the difference in appearance, the microphone of the collar clip is more compact and delicate, while the shape of the gun microphone is cylindrical like the barrel.

② Different directions.
Most lavalier microphones adopt omnidirectional pickup mode, which can pick up 360 ° sound source around the microphone, and some models also have low cut function, which can effectively reduce the pickup of ambient sound.

Shotgun microphones are mainly supercardioid and cardioid pointing, mainly picking up the sound source in front of the microphone, while picking up the sound source in other directions will gradually weaken.

③ Different usage scenarios
The lavalier microphone has a wide range of applications and is compatible with recording devices such as mobile phones, computers, SLRs and video cameras. The signal transmission is stable, the anti-interference ability is strong, the microphone sensitivity is high, and the pickup is clear.

Shotgun microphones are mostly used with a combination of SLR and camera, and have strong pickup ability at medium and short range. When you are in a noisy environment or when you are recording from a long distance, the clarity of the sound quality will be reduced.

Both of them have their own advantages and are suitable for different use needs. Shotgun microphones are suitable for close-range use with fixed scenes, angles, and no need for extensive movement. The characteristics of the lapel microphone are destined not to be limited by the scene and distance, and it can also receive sound at any time in the process of moving.

IV. Analysis of Configuration Parameters of Shotgun Microphone
1. Type of Shotgun Microphone
Shotgun microphones can be divided into short, medium and long types according to the length of the tube body.
① Short Shotgun Microphone
The pickup angle is generally in the range of 60 ~ 70 °. Affected by the length of the gun body, it is easier to pick up the surrounding noise in the off-axis direction.
② Medium Shotgun Microphone
The pickup angle is generally between 40 ° and 50 °, and the pickup range is small, which can effectively reduce the impact of off-axis environmental noise.
③ Long Shotgun Microphone
The pickup angle is generally about 30 °, so as to minimize the pickup of noise in the off-axis direction and obtain clear sound quality. Because the tube body is too long and the pickup angle is relatively narrow, it is necessary to aim at the direction of the sound source when recording in order to achieve high-quality pickup effect.

2. Shotgun microphone parameters
If you want to buy a gun and microphone suitable for your own use, you should do your "homework" well. We should pay attention to the following parameter configurations:
① Sensitivity
Sensitivity refers to the ability to convert between a human voice signal to a level signal, expressed in -dB or V/Pa.
The higher the microphone sensitivity, the clearer the sound quality will be.
② Frequency response
Frequency response refers to the response of the microphone to different frequencies, which is used to describe the bandwidth range of the signal audio.
In most cases, the smoother the microphone's frequency response, the better the recording.
③ Signal-to-noise ratio
The ratio of the sound source output power to the noise power is called the signal-to-noise ratio and is expressed in dB.
The higher the signal-to-noise ratio, the lower the noise in the signal and the higher the sound quality.
④ Output impedance
In a circuit, the resistance to current flow is called impedance and is represented by Ω.
Most of the time, the lower the output impedance of the microphone, the higher the sensitivity and the better the sound quality.