Have you ever trying to find a microphone that is best suitable for your recording but ends up figuring out what those technical specs mean? I’m here to help, after you finish reading this post, you will be able to know which microphones are needed for your applications. This is the ultimate guide to studio microphones…
- TYPES OF MICROPHONES
- POLAR PATTERNS
- FREQUENCY RESPONSE
- OUTPUT IMPEDANCE (Z)
- MAXIMUM SPL
- SIGNAL TO NOISE RATIO (S/N)
TYPES OF MICROPHONES
Microphones can be grouped into 3 different types, based on how they convert sounds to electronic signals.
A dynamic microphone consists of three parts, a diaphragm, a voice coil that attached to the diaphragm, and a permanently charged magnet that creates a magnetic field. When sound waves hit the diaphragm and vibrate the voice coil in the magnetic field, it generates electronic signals that can be converted to audio or digital signals.
Dynamic microphones are less sensitive but more durable, they can handle loud sound like snare, kick or guitar cabinet. They are also great for live shows.
Check out the best dynamic microphones on the market:
A condenser microphone also consists of three parts, a conductive diaphragm and a metal backplate that both are charged with an internal or external power source (battery or phantom power), and a diaphragm case holding everything together. When sound waves hit the diaphragm and push it closer and further away from the metal backplate, the variation of the space between the diaphragm and the backplate will generate electronic signals.
Condenser microphones are more sensitive but less durable. They can respond to detailed sounds and have wider and smoother respond. Based on the size of diaphragms, it can be divided into 2 types of condenser microphones.
Large Diaphragm Condenser
Large diaphragm condenser microphones have a better low-end response. They are widely used in vocal tracking, overhead and room.
Small Diaphragm Condenser
Small diaphragm condenser microphones are very precise and have a better transient response. They are ideally for hi-hat, cymbals and piano.
Check out the best condenser microphones on the market:
Ribbon microphones operate almost as same as dynamic microphones but instead using heavy voice coil, the ribbon microphone has a very thin metal foil that is suspended in a strong magnetic field, which makes it respond much more natural to the original sound.
The advantage of ribbon microphones is they have warmer and flatter respond. However, ribbon microphones are very fragile because of their thin foils, air blast produced by vocal and drum or even hitting the case can easily break the foil.
Ribbon microphones can be used whenever you want the warm and natural sound, they are great for brass instruments and room.
Believe it or not, just like condenser microphones, some ribbon microphones also need an external power source to use, they’re called active ribbon microphones.
Passive ribbon microphones don’t need an additional power source, connect them with the 48V phantom power will blow the ribbon away. Passive ribbon microphones have incredible sound performance, but they are less sensitive and the sound performance really depends on the impendence of preamps.
Active ribbon microphones require phantom power to work. You don’t have to run the risk of accidentally blowing up the ribbon. Active ribbon microphones are more sensitive and the frequency response is more consistent no matter which preamp is using.
Check out the best ribbon microphones on the market:
Polar pattern is how microphones pick up sounds from different directions, based on how they respond, it can be divided into several patterns.
Omnidirectional microphones pick up sounds from every direction, which make them great for capturing room sounds.
Cardioid microphones pick up sounds in front of them and reject sounds behind them. They are directional microphones and can be used for only pick up the sound you pointing to while rejecting background and ambient noise.
Supercardioid and Hypercardioid
Supercardioid microphones are more directional than cardioid microphones, and hypercardioid microphones are even more so. The only difference is supercardioid and hypercardioid microphones both have small rear lobes that also pick up sounds. Rear lobes in supercardioid microphones are smaller.
These super directional microphones have great isolation that is good for separating your tracks, but the rear lobes can make them tricky to mic up.
Figure 8 microphones pick up sounds equally from front and back but reject sounds from sides. They are great for stereo miking technique, which crossing 2 microphones at 90 degrees.
Multiple pattern microphones have switchable polar patterns, this feature is common on professional condenser microphones.
The frequency response of a microphone is the range of frequency that microphone can reproduce. Ideally, you will want your microphone has a wider frequency response than the sound you are going to record and has a low frequency roll-off below the fundamental frequency of the sound so that you won’t record unwanted sub low frequencies. Some microphones will have a low cut switch.
OUTPUT IMPEDANCE (Z)
Impedance is the resistance to an audio signal which measured in ohms. Microphones with a lower impedance will lose less high frequencies and pick up less noise over a long cable. Normally, impedance between 150 and 600 ohms is low. 1000 – 4000 ohms is medium, and over 25,000 ohms is high.
SPL stands for sound pressure level, it means the loudness of a sound. The quietest sound human can hear is 0dBSPL. A microphone with a Maximum SPL of 120 dB means sounds will start to distort when recording a 120 dB sound. Microphones that have over 120 dB of maximum SPL are good. Some microphones have a pad button to prevent distortion and clipping.
The sensitivity of a microphone is how strong the output signal when exposed to specific SPL. High sensitivity microphones have a stronger output signal than low sensitivity microphones when exposed to the same loudness of sound. You will need to pull more gain up when using low sensitivity microphones, this results in more noise, so if you are recording a quiet sound, use high sensitivity microphones, and if you are recording a loud sound, you can use low sensitivity or high sensitivity microphones, since the sound is way louder than noise.
Here are some common sensitivities of different types of microphones.
- Condenser: 5.6 mV/Pa (high sensitivity)
- Dynamic: 1.8 mV/Pa (medium sensitivity)
- Ribbon: 1.1 mV/Pa (low sensitivity)
Self-noise, or equivalent noise level is the electrical noise generated by the microphone itself. You will only see this specification on condenser microphones and active ribbon microphones since only them need to be charged by an additional power source. Sometime you will see passive ribbon microphones also state their self-noise, that’s related to the output impedance. Normally, self-noise is A-weighted, which adding filters to the measurement to simulate the human perception.
The lower the self-noise, the better.
- 10- db-A is excellent. It’s almost impossible to notice any noise.
- 11-15 db-A is great. You must solo the track and really pay attention in order to hear some slight noise. You are unable to hear any noise in the mix.
- 16-19 db-A is good enough. The noise will only become apparent when recording some quiet sounds. Normally the noise is very subtle in the mix.
- 20-23 db-A is not bad. You can start to hear some noise, but it will only happen when you record anything below normal speaking level.
- 24+ db-A is bad. The noise is loud enough to affect the overall music-listening experience. Avoid buying microphones with this self-noise value.
SIGNAL TO NOISE RATIO (S/N)
The signal to noise ratio is the self-noise relative to the SPL at 1 Pa, which is 94 dB. So basically, the signal to noise ratio of a microphone is 94 dB minus its self-noise. For example, a microphne with the self-noise of 10 dB-A, its signal to noise ratio will be 84 dB-A. Microphones with higher signal to noise ratio can record your source from a more distant place because the microphone will be less likely to pick up noise. However, the actual signal to noise ratio depends on how loud is your source.