When people hear the word “microphone,” they usually think purely about recording sound. But microphones don’t just record sound, many of them also amplify it. Gain on a microphone refers to that amplification, the amount of power applied to boost a microphone’s signal during recording.
This guide covers what gain is, how it works, what it does on a microphone, and how to increase or decrease it.
Quick verdict: if your recordings sound too quiet, raise your gain gradually until you reach a clean, strong signal. If you’re hearing distortion or clipping, lower the gain first before troubleshooting anything else in your setup.
What Is the Gain of a Microphone?
Microphone gain is a core concept in amplifiers and other telecommunications equipment. In this context, gain measures how much larger an output voltage or current is compared to the input. Put simply, gain is the ratio between output and input voltage or current.
How Does Gain Work?
Within telecommunications equipment, gain can be thought of as a multiplication factor between input and output, often expressed as a ratio raised to some exponent.
Digital cameras offer a useful comparison. They translate photon data into digital data, and during that process, electrons from the sensor pass through a preamplifier. Gain is the amplification applied by the sensor at that stage, which boosts both the intended signal and any background noise along with it.
This is part of why low-light situations, and heavily amplified analog circuits like older tube amplifiers, tend to come with noticeably more noise.
What Does Gain Do on a Microphone?
The gain level on a microphone depends on the strength of the incoming signal, and it can be increased or decreased depending on what you’re trying to achieve.
Microphones have long been used to amplify sound for human hearing, but the role of gain has expanded as microphone technology has advanced to pick up sound types beyond what we can naturally hear. A few examples:
- Medical ultrasound machines use a high voltage amplifier to boost an ultrasonic signal enough to be detectable
- A cell phone’s built-in microphone can pick up high-frequency signals like certain radio waves
- Gain is sometimes turned down deliberately to capture very faint sounds, such as recordings of distant astronomical phenomena
- In recording contexts, gain is often referred to as sensitivity and measured in decibels
Researchers also use specialized recording equipment to amplify infrasonic signals, frequencies below human hearing, such as the rumbling associated with earthquakes.
Your gain setting controls the level of distortion in your tone, independent of your final output volume. In other words, gain determines how clean or distorted your sound is, regardless of where your master volume happens to be set.
Can You Increase or Decrease Gain?
Yes. Gain is the amplification applied to an audio signal entering a microphone, and you can adjust it in the traditional way, turning it up or down, or through more advanced methods depending on your equipment.
How Do You Increase the Gain on a Microphone?
There are a few ways to increase gain. One option is using an external power source to boost your signal and improve sound quality. This approach is better suited for more experienced users, since it requires some familiarity with handling electronic equipment. If you’re working with an XLR microphone, pairing it with a microphone preamp or an audio interface is a common way to do this properly.
You can also adjust the gain setting directly on your device, which requires some understanding of frequencies and how they interact with your equipment. Since sound travels in waves, increasing both the high and low frequencies generally increases a sound’s amplitude.
Lowering your output volume can also effectively increase gain, which is particularly useful for portable devices, since keeping output volume lower can help preserve battery life without sacrificing overall sound quality.
How Do You Decrease the Gain on a Microphone?
Sometimes you need to reduce gain, whether to prevent distortion or simply because a signal is too loud for your recorder. There are a few ways to approach this, each with tradeoffs.
The simplest method is increasing the distance between the microphone and the sound source. For example, if you’re recording a singer and they’re getting too close to the microphone, moving the mic back slightly reduces gain naturally.
You can also use the microphone’s attenuation switch, sometimes labeled “attenuator” or “pad,” which typically offers two settings: 0dB or -10dB. This kind of pad switch is common on many condenser microphones in particular.
Most microphones default to the 0dB setting. Switching to -10dB reduces gain, after which you can re-adjust the mic position or settings until you reach a clean recording level.
FAQ
Does gain affect sound quality?
Yes. Too much gain can introduce distortion into your recording.
What happens if the gain is too low?
If gain is set too low, your recording will sound quiet, requiring you to play it back at a higher volume to hear it clearly.
What’s the difference between low gain and high gain settings?
The difference comes down to sensitivity. A low gain setting decreases your microphone’s sensitivity, while a high gain setting increases it.
What is gain on a mic, in simple terms?
Gain is an increase in volume or signal intensity, and it’s a fundamental part of how audio recording works.
What’s the best way to reduce gain?
The most reliable way to reduce gain is adjusting your distance from the sound source you’re recording.
Is gain the same as overdrive?
Not quite. Gain refers to the amount of signal clipping or distortion added to a signal, while overdrive is a specific form of that distortion.
Conclusion
Understanding gain is essential for getting the best possible audio quality from your recording setup. Whether you need to increase gain through a preamp or external power source, or decrease it using distance or an attenuation switch, getting this setting right has a direct impact on how clean your final recording sounds.
For more on getting clean, high quality recordings, see our guides on easy hacks to improve microphone sound quality, how to make your voice deeper on the mic, and how to stop microphone from picking up keyboard noise.
