Choosing the right microphone can be daunting, given the vast array of options available. Understanding microphone specifications is crucial for making an informed decision. This guide will break down the key specs and explain How To Compare Microphones effectively.
Different types of microphones for various recording needs.
The decibel (dB) scale, the foundation of most microphone specifications, measures sound intensity logarithmically, mirroring human hearing perception. A 3 dB change is noticeable, while 10 dB is perceived as double or half the loudness.
Understanding Directional Patterns
A microphone’s directional pattern, visualized in a polar plot, illustrates its sensitivity to sound from different directions. Common patterns include:
- Omnidirectional: Captures sound equally from all directions.
- Cardioid: Primarily captures sound from the front, rejecting sound from the rear. Variations like supercardioid and hypercardioid offer greater rear rejection but with some rear sensitivity.
- Figure-of-eight: Captures sound equally from the front and rear, rejecting sound from the sides.
Visual representation of microphone polar patterns.
Polar plots often display multiple frequency responses, showcasing how directionality changes across the audio spectrum.
Microphone Operation Principles
Microphones operate on different principles:
- Pressure: The diaphragm responds to sound pressure from one side, resulting in an omnidirectional pattern.
- Pressure-gradient: The diaphragm responds to pressure differences on both sides, creating directionality. Most directional microphones utilize a combination of pressure and pressure-gradient principles.
- Interference tube: A tube in front of the diaphragm enhances on-axis sensitivity and rejects off-axis sound.
Diagram illustrating pressure and pressure-gradient microphone principles.
Key Microphone Specifications
Frequency Response
Frequency response indicates the range of frequencies a microphone can accurately capture. A flat response reproduces all frequencies equally, while a tailored response emphasizes specific frequencies for particular applications.
Example of a microphone frequency response curve.
Sensitivity
Sensitivity measures a microphone’s ability to convert sound pressure into electrical voltage. Higher sensitivity requires less amplification, beneficial in quiet environments. It’s measured in millivolts per Pascal (mV/Pa) or decibels relative to 1 Volt per Pascal (dBV/Pa).
Chart comparing microphone output voltage at different sound pressure levels.
Equivalent Noise Level
Equivalent noise level, or self-noise, represents the microphone’s internal noise floor. Lower noise levels are crucial for capturing quiet sounds without unwanted hiss. It’s measured in dB(A), weighted to reflect human hearing sensitivity.
Total Harmonic Distortion (THD)
THD quantifies the amount of distortion introduced by the microphone. Lower THD values indicate cleaner sound reproduction. Specifications usually state the maximum sound pressure level (SPL) at which THD remains below a certain threshold, typically 1%.
Graph illustrating the relationship between sound pressure level and total harmonic distortion.
Maximum SPL
Maximum SPL indicates the highest sound pressure level a microphone can handle without excessive distortion or damage. This is crucial for recording loud sources.
Beyond the Specs: Real-World Considerations
While specifications provide valuable data, listening tests are essential for evaluating a microphone’s subjective qualities like detail, clarity, and overall sound character. Consider the intended application, recording environment, and personal preferences when making your final decision. Remember, the best microphone is the one that sounds best for your specific needs. For example, a lavalier microphone:
Sensitivity comparison between two microphones.
is best suited for capturing speech in close proximity, whereas a large diaphragm condenser microphone:
Sensitivity expressed in different units.
might be preferred for recording vocals or acoustic instruments in a studio setting. Furthermore, understanding on-axis and off-axis responses:
On-axis and off-axis frequency response curves for a cardioid microphone.
helps determine how a microphone will perform in different acoustic environments. Finally, knowing the different microphone cartridge types:
Multiple frequency response curves for a professional microphone.
will allow you to choose the best option for your specific recording needs.
