The diaphragm is an essential component of a microphone, responsible for converting sound waves into an electrical signal. The size of the diaphragm plays a significant role in determining the microphone’s frequency response and sensitivity.
Here are a few characteristics of microphones with different diaphragm sizes:
- Large diaphragms: Microphones with large diaphragms, typically greater than 1 inch in diameter, are known for their smooth and warm tonal character. They are often used in recording studios for vocals, acoustic instruments, and drums. Large diaphragms also have a wider frequency response, making them more versatile in a variety of applications.
- Medium diaphragms: Microphones with diaphragms ranging in size from 0.75 to 1 inch are often used in broadcasting and live sound reinforcement applications. They offer a good balance between sensitivity and frequency response, making them suitable for a wide range of sources.
- Small diaphragms: Microphones with small diaphragms, typically less than 0.75 inch in diameter, are known for their fast transient response and high SPL handling capability. They are often used in drum miking, percussion recording, and other high-volume applications. Small diaphragms also tend to have a brighter tonal character, making them well suited for sources that need to cut through a mix.
Diaphragm sizes affects the tonal character captured because of several physical factors that come into play in the design of the microphone :
- Surface Area: The larger the diaphragm, the greater its surface area, which means that it can move more air and respond to a wider range of frequencies. This results in a wider frequency response, which can pick up a broader spectrum of sounds and produce a more natural, warmer tonal character.
On the other hand, smaller diaphragms have a smaller surface area, which makes them more responsive to fast transients. This results in a faster transient response, which allows the microphone to capture the details of percussive sounds and other high-energy sources more accurately. - Mass: The larger the diaphragm, the more mass it has. This increased mass allows the diaphragm to respond more slowly to fast transients, which produce a smoother and warmer tonal character.
On the other hand, smaller diaphragms also have less mass, which means that they can respond more quickly to changes in air pressure. This allows the microphone to handle high SPLs, making it suitable for recording sources with high volume levels, such as drums and percussion. - Suspension: The larger the diaphragm, the more it needs to be suspended, because how it suspended can affect its response to low-frequency sounds. This is why, larger diaphragm microphones typically use thicker suspensions to preserve the low-end response and maintain the warm tonal character captured.
On the other hand, smaller diaphragms are typically suspended with lighter materials, which can contribute to their fast transient response and ability to handle high SPLs. The lighter suspension also allows the diaphragm to respond more quickly to changes in air pressure, making it perform much better in capturing high-volume sources.