What is the basic definition of sound level meter frequency weighting?
1. Sound level frequency weighting
The basic definition of sound level meter frequency weighting refers to the difference between its constant-amplitude steady-state sinusoidal input signal level and the indicated signal level on the display device as a function of frequency, and the frequency weighting is expressed in decibels (dB) . The frequency weighting of the sound level meter usually has A, B, C, and D weighting, which are different weighting networks designed in the circuit of the sound level meter to simulate the different sensitivities of human hearing at different frequencies. The sound pressure level measured through the weighting network is called the weighted sound pressure level, such as the A-weighted sound pressure level, also known as the A sound pressure level; the sound pressure level that does not pass through the weighted network is called the linear sound pressure level, and the Z-weighted sound pressure level is currently used pressure level representation.
A, B, and C weightings respectively approximate three equal-loudness curves of 40, 70, and 100 fangs. Since A-weighting can better characterize the subjective characteristics of the human ear, A-weighting sound levels are often used to represent noise in noise measurement. The size of the C-weighted sound pressure level and Z-weighted sound pressure level are often expressed as the total sound pressure level in noise measurement, and D-weighted is dedicated to the measurement of aircraft noise.
2. Polarized condenser microphone, sensor
Classification of microphones
According to the principle of sound-electric conversion, it is divided into: electric type (moving coil type, aluminum belt type), capacitive type (DC polarization type), piezoelectric type (crystal type, ceramic type), electromagnetic type, carbon particle type, semiconductor type wait.
There are two types of condenser microphones, one is microphone type, such as the microphone in KTV. This kind of condenser microphone uses a battery-powered handheld condenser microphone, usually AA batteries; another kind of condenser microphone is a recording microphone, such as a recording microphone in a radio studio and a recording studio. This condenser microphone needs 48 volts of phantom power for power supply.
Compared with other microphones, the characteristics of condenser microphones are:
1. The clarity of the sound is good
2. It has ultra-high sensitivity. The reason is that because there is no voice coil load on the vibrating membrane, it can adopt an extremely thin and light design, so not only the frequency response is extremely superior, but also it has excellent sensitivity, which can sense extremely weak sound waves and output the clearest, most delicate and accurate original sound !
3. The output sound quality is full and thick but not muddy.
4. Fast transient response characteristics. The ability to respond quickly and slowly to sound waves is more responsive than other microphones.
5. It has the characteristics of ultra-low touch noise. The reason is that the diaphragm of the condenser microphone is relatively light, which inherently has the excellent characteristic of "ultra-low touch noise".
6. It has the characteristics of drop resistance and impact resistance. Condenser microphones are small in size and light in weight due to the ultra-thin diaphragm.
What is a condenser microphone
Condenser microphones are the best microphones for recording, and their uses include solo vocals, saxophone, flute, pipe or woodwind instruments, acoustic guitar, or acoustic bass. Condenser microphones are suitable for any occasion where sound quality and clear sound are required. Due to their rugged construction and ability to handle high sound pressure, condenser microphones are an excellent choice for live sound reinforcement or live recording.
Another commonly used condenser microphone is called an electret microphone. The electret microphone has the characteristics of small size, wide frequency range, high fidelity and low cost. It has been widely used in electronic products such as communication equipment and household appliances. The diaphragm of the electret microphone has been subjected to high-voltage polarization treatment during production, and will permanently carry a certain charge, so no additional polarization voltage is required. For portability and other requirements, the electret condenser microphone can be made small, so it will affect the sound quality to a certain extent.
