Microphone gain can be very confusing at first, especially when you hear the word gain all over the music production industry.
But don’t worry, you’ve come to the right place!
By the end of this article, you will know everything you need about mic gain, from why it’s important to how you can make the most of it!
Are you ready? Let’s dive in!
- Mic-level signals are too weak to be recorded, so they need gain to boost them to line level.
- Gain boosts the input, while volume boosts the output
- The gain comes from an external energy source, so you will need an audio interface, a mic preamplifier, or an active microphone with a built-in active amplifier.
- Setting the ideal gain is very crucial to maintaining a good quality of sound in your audio recording.
What Is Gain?
The word gain is easily thrown around in the music industry, but what does it mean?
Gain control is sometimes used interchangeably with other terms, distortion, and volume, but they are not the same.
Gain can be added without distorting the signal. Adding gain can also boost volume, but gain and volume are very different from each other as well.
Microphone gain refers to the amplification of audio signals. It answers the question of, what has the signal gained from being amplified?
Microphone gain is how much you increase the level of your output volume. Microphone gain works by adding energy to a weak signal from a mic.
It is when energy is converted using an external power source like a wall plug, phantom power, or batteries.
Microphone gain raises the signal’s amplitude from mic level to line level so that it can be used by professional audio equipment.
How Loud Can Microphone Gains Be?
We set microphone gain control since microphone outputs tend to be quiet, ranging from -30 to about -70 decibels.
This number needs to be increased so that it can be set to a level we can work with.
We need standalone preamps, active microphones, or built-in mic amplifiers in audio interfaces.
A mic amplifier usually provides an additional 48-volt phantom power to the mic input signal.
Mic Level Signals and Line Level Signals
A microphone’s output is a mic-level signal, usually between −60 dBu and −40 dBu.
Meanwhile, a line-level signal is the output of line inputs like musical instruments. Line level signals are usually around 100 to 1,000 times stronger than mic level signals.
This is where mic gain comes in. For equipment like audio interfaces to pick up both line level and mic level signals, we need gain to boost the mic signal to match the line level signals.
As mentioned above, your mic preamp can be either standalone or built-in to your interface.
This preamp expects mic inputs, so it is equipped to supply enough makeup gain to boost it to equal signal strength to line level.
But do be careful when plugging your inputs. Only mics can be plugged into a mic preamp, and plugging a line-level output in it can damage the mic preamp.
On the other hand, plugging your microphones into line inputs will result in very low electronic signals. You might not be able to hear the voice recording later.
When setting up your equipment, ensure that your line input is only plugged into a line-level preamp and that the same is done for your mics.
Gain From Active Microphones
Aside from interfaces and mic preamps, the gain can also come from an active preamplifier in active microphones.
Some condenser mics, active mics, or USB mic have built-in amplifiers in the microphone body.
Because the audio signal from the mic capsule is too low, these mics put a built-in active amplifier directly after the mic capsule.
This way, voltage is automatically increased, and the high signal impedance is automatically brought down.
These active microphones also come with attenuation pad switches. This reduces the audio signal’s amp before reaching the capsule’s amplifier.
How Does Gain Affect Recording Volume?
When the input signal is passed through an amplifier, and the audio signal comes out twice as big, you have a gain factor of two.
The gain factor you get depends on the gain range that your amplifier has.
Gain is what makes your microphone louder. So the higher you set the gain control to, the louder the volume is.
In recording volume, the gain depends on the loudness of the sound source.
So, if you’re recording microphone signals and the person singing or talking is too loud, you will have to lower your gain to adjust to the input signal.
Or if the instrument, say a guitar amp you are recording, is too quiet, you need to set your gain higher.
What Happens if Gain is Too High
The level you set your microphone gain to will significantly affect the sound quality of your audio.
If your gain control is too high, your mic signal might get clipped. And if you are recording a digital signal, it can even distort your digital audio.
Now, if you create distortion or clipping in digit audio while recording, there’s nothing you can do to salvage it.
Even your digital audio workstations or mixing console can hardly do anything.
Additionally, when too much power is used when the gain is set too high, it can damage your professional audio equipment.
What Happens if Gain is Too Low
On the other hand, if your gain control is set too low, you might not hear any audio signal at all.
When the preamp signal on your mic is set too low, the microphone signal will get mixed up with the noise floor of your audio interface, and it could even get lost.
Because the signal-to-noise ratio is too low, you might hear only hiss.
Now, what can your digital audio workstation do? You will have to boost your recorded microphone signal high to be able to hear it.
And the dilemma in boosting recorded audio signals is that you don’t get to increase the volume controls of only the microphone signal selectively.
The entire input signal is boosted. This means the noise floor gets boosted, so you end up with loud but bad-quality audio.
How to Find the Perfect Gain Level
Setting up your gain controls to the ideal level is essential to achieving the optimal levels of your analog-to-digital converters.
Different factors go into gain adjustment and finding the perfect gain level, and there is no one perfect formula for setting it up for your specific preamp.
So instead, let’s look at the different variables you need to pay attention to when setting up your microphone preamp or audio interface:
1) Sound Source Volume
Microphone gain and volume are very closely related.
As mentioned earlier, the gain adjustments you must make will first depend on the source of your mic signals.
You need enough gain to compensate if the sound source has a weak signal. Inversely, if the mic signal source is too loud, you have to lower your gain.
Too much or too little gain will heavily affect how the audio will be recorded and kept.
2) Distance From the Sound Source
Next, I need to look at the distance between the sound source and the microphone, as this will affect mic signals and their volume.
If I were standing at the right distance from the mic, my voice would be heard much louder than if I stood a foot away from the mic.
So, the farther the sound source is from the mic, the lower the volume. And with a lower volume of mic input, you will have to set the microphone gain significantly higher.
If the sound source is much closer, you will get a higher mic input volume. Then you can adjust the microphone gain to a lower setting.
3) Microphone’s Sensitivity
The last factor in adjusting your microphone gain is the mic output level or the signal output per sound pressure level.
You will need more microphone gain if your professional microphone is more on the quiet side, like a dynamic or a ribbon mic.
Meanwhile, you can set the microphone gain to a lower level using a louder mic like a standard condenser mic.
How to Set up the Ideal Microphone Gain
So now that you know what variables affect the gain let me walk you through setting it up!
Step 1: Find the Right Microphone Proximity
The first thing you want to set up is your distance from the microphone. It’s important to set this up correctly before anything else because it will affect all the other variables.
So first, get into the standing or sitting position you normally take when recording.
From that position, measure six inches from your mouth to the microphone capsule and set your microphone there.
An easy way to estimate this is to use the distance from your thumb to your pinky finger.
If your thumb touches your mouth and your pinky finger touches the mic capsule, you’re at the right distance since that’s about 6 inches!
This distance from the mic will give your recording the ideal tone and reduce the number of reflections.
A reflection is a sound wave that bounces around your room before being picked up by your mic. Reflections of sound waves are more common in smaller rooms.
The nearer you are to the mic, the more direct sound it picks up, and the fewer reflections get recorded.
The farther you are from the mic, the less direct sound gets picked up, and more reflections get recorded.
Lastly, you want to maintain the six inches of distance to control the proximity effect.
The farther you are from the mic, the less low and top end gets picked up by the mic. You want to ensure that all the best parts of your voice make it into the recording.
Step 2: Set up the Mic Gain
Next is trying out how it sounds. Start by speaking to the mic as you normally would test the volume level.
You can also speak or sing in your usual highest recording voice to test if the mic will still be able to record it well. Then, you can adjust the gain on your preamp of the interface accordingly.
While you turn the knob, keep an eye on the meter on your DAW. You want to ensure that the green level hits as high as it can without touching red.
Touching red means your recording is not good enough to be used, so you want to set your levels to only green.
This way, you can rest assured that your recording won’t clip or create distortion when you record.
Frequently Asked Questions (FAQs)
Are you still curious about a few more things about the microphone signal and some gain controls? I’ve got you!
Is Gain Different from Volume?
In the gain vs. volume confusion, you must remember that gain is adjusted for the input signal, while the volume control is only for the output signal.
Volume refers to the loudness of the output channel. You adjust it on your speakers, studio monitors, headphones, and other audio devices.
Adjusting the microphone volume will affect mic signals in terms of loudness but not tone.
Meanwhile, mic gain control is adjusted during the input process. A microphone’s gain control knob can be found in either the audio interface or the microphone preamps.
Microphone gain adjustment will affect the tone but not the loudness.
Should I Turn My Mic Gain All the Way Up?
It would be best if you never turned your gain up unless your audio signal is bad. Not only will it distort and clip your recording, but it can also damage your audio equipment.
Does Gain Affect Sound Quality?
Gain staging affects the sound quality. The adjustable gain controls your system’s response to the signal you send.
If your mic gain is too low, your audio will pick up noise. However, if your mic gain is too high, it will clip and get distorted.
Setting the gain controls to their ideal levels is crucial to recording good quality audio.
Is Microphone Preamp Gain the Same as the Gain on My Guitar Amp?
Both gains of microphone and guitar amplifiers are gains in electrical impulses.
Both microphones and guitars produce weak signals; both must be amplified in some way to be recorded in a studio.
The only difference is that guitar amps still sound good when both preamps are overdriven, while mic preamps sound bad.
And that’s everything you need to know about mic gain and how to set the perfect gain levels!
With the knowledge of how microphones work, it will be easier for you to record audio in the highest quality possible.
We hope this article has been informative and helpful to your music production journey. Thank you for reading!