How to Reduce Background Noise On Mic

For any artist, background noise can ruin your song. Or maybe you’re a broadcaster who is trying to improve your sound before you go live. Regardless, you’ve come to the right place if you want to take your sound to the next level.

Fortunately, there is a technology that helps with eliminating unwanted noise. You’ll learn the different forms of background noise and some tips on how to prevent it from interfering with your sound.

Let’s get started!

What is Background Noise?

Background noise is any other sound that the recording artist does not create. When recording, any external noise (fans, outside speech, water waves, etc.) can interfere with the sound and lower the final recording result.

Types of Background Noise

Here are the three main forms of background noise:

Impulse noise has a short duration and a high frequency. This includes sharp sounds like pops and clicks on a mic.
Narrowband noise is found in narrow frequency ranges. This noise has an audio level created by poorly shielded cables and incorrect grounding connected to microphones. Basically, narrowband noise is an unwanted signal that remains steady over a period of time.
Broadband noise is continuous noise where the acoustic energy travels through multiple frequencies once the microphone picks up the sound. Sounds such as static noise and hisses fit into this category.

How to Reduce Background Noise?

When recording, you’ll want to remove as much background noise as possible. Here are some ways to help remove unwanted sounds from your audio production.

Before Recording

The best way to remove background noise is to not have a noisy environment, to begin with. This means that you should record in the quietest environment possible. While you don’t need a professional recording studio, you need to pick the quietest area you can find.

Then, you’ll want to check the ambient sounds in the background.

Can you hear people outside or other large trucks outside? What about the air conditioning or heating system? Is there a fan nearby that’s making any noise? Is there a buzzing sound from the fluorescent light?

Next, you’ll want to make a test recording of your room. You don’t have to talk, but you need to have a microphone for your voice-over recording. Take time to record 10-20 seconds of the noise that’s present in the room.

This is known as the recording room tone. Next, listen to the tone recording in your headphones. What sounds that you hear can you eliminate?

For example, if people are talking within your vicinity, you can politely ask them to tone it down. Or, if there is a fan that’s blowing, you can turn it off to help preserve the sound of your audio recording.

RFI Filter

When recording, you might run into radio frequency interference (RFI). For example, if you’re using a microphone near a radio station or city, your microphone signals might experience RFI.

Some microphones have a more sensitive RFI content than others. To help reduce the RFI from your microphone, use an RFI filter. This will help keep external noise from interfering with your sound.

Place Your Mic In a Mic Input

A straightforward way to create unnecessary noise in your microphone signal is to connect your mic to a signal that’s not compatible with it.

Mic inputs are balanced and expect a mic signal. Placing a microphone in a mic input ensures that the signal will be transferred to the circuit that works with it.

For instance, if you place a microphone through a line input, we’ll have a serious issue. That is because the line signal is expecting a 10 – 1000 times more powerful signal than the microphone’s signal.

The noise in the input can become loud or even louder than your microphone level signal.

DAW Noise Suppression Plugins

If nothing else works and you have a noisy vocal track in your DAW, you can use noise reduction plugins to improve their quality.

In addition, if you have a powerful computer with good processing power, you can use a noise suppression plugin when monitoring or recording your mic signal.

Find a Quiet Recording Environment

To improve your recording quality, reduce the ambient noise in your area.

A great example of this is the standard soundproof sound isolation booth. This booth is heavily soundproofed so that no external sound will appear from the outside. And there are padded walls that create an acoustic environment where the sound doesn’t bounce off the surfaces.

With a sound source in the iso-booth, the noise will be reduced in comparison to other environments. In the most extreme case, an anaerobic chamber, which doesn’t have ambient noise whatsoever.

That being said, going to a quieter environment helps reduce noise. Here are some non-obvious methods to prevent noise from entering our environments:

When recording in an office, record away from refrigerators, heat pumps, fans, etc.
Get the artist to stay still while recording to reduce background noise from footsteps, clothing, etc.
When recording outside, steer clear from construction, street traffic, etc.

Create a microphone isolation shield to lower the number of room reflections.

Get a Shock Mount

Mechanical noise is defined by solids captured by the microphone and makes noise in the mic signal. Shock mounts are used to create isolation from this mechanical noise, which helps reduce the overall mic noise.

There are two types of shock mounts:

External Shock Mounts: It’s common to see external shock mounts in professional recording studios. They use different types of fabric to reduce the amount of mechanical noise from the microphone stand.
Internal Shock Mounts: These shock mounts come pre-installed in the microphone. They mechanically isolate the cartridge/capsule from the microphone’s body.

Use a Pop Filter to Remove Unwanted Sounds

You should get a pop filter if you want to remove any sibilance and plosives from your recording. Pop filters are not suited for outdoor areas and are generally useful for home studios. It acts as a filter between the microphone and the speaker/singer.

Pop Filters include a round disc object that is mounted on a mic stand and a boom to position it where it’s needed. This filter reduces or eliminates plosives, so the microphone will help with removing noises in the background.

Also, it removes moisture from the mic, which improves the longevity of your equipment.

Filters for Static Noise, Hum, Hiss, and Additional Sounds

Consider getting a filter if you are having unwanted noise coming from your audio setup. Filters are used to utilize signals within a certain frequency range and remove signals that are associated with unwanted microphone sounds and background noises.

Here are five basic microphone filters:

Band-Reject filters have an opposite function to bandpass filters. It’s used to remove unwanted noise by removing the loud frequencies and affecting other frequencies.
High pass filters are used when there is no need for low-frequency signals. It is the opposite of low-pass filters that removes signals that are under its cut-off frequency.
Phase-Shift (or All Pass) filters do not affect the signal’s amplitude. It functions to change the signal phase without changing the amplitude.
A bandpass filter is used to separate a signal in one frequency. Alternatively, it can work with a band of frequencies from multiple frequencies.

The most common filter is the high-pass filter that reduces the low-frequency sounds from a mic or audio signal. Start with 20Hz and increase the frequency until you find the right spot without interfering with the sound source.

For instance, start with 120 Hz with female vocals and 100 Hz for male vocals. You should experiment with this to get the best noise reduction. Filters are a great option if you want to remove static from your sound recordings.

Use a Noise Gate

Noise gates are used to reduce background noise and unwanted external sounds. It doesn’t allow an audio signal to pass by only once it reaches a threshold value. Basically, it’s used when the audio signal level is above the noise.

If it is set correctly, the noise gate will reduce the hum from the power system and the loud amplifier noise without changing the sound source. With some slight adjustments and a noise gate, you can remove the static audio or background noise your microphone picks up.

Here are the five main types of noise gates:

Attack – Determines the time it takes for a gate to go from an open to a closed state.
Ratio – The balance between the gated sound and original sound.
Release – Determines how long it takes for the gate to go from open to closed. A slow-release sounds like a fade-out. Meanwhile, a fast release turns off the sound quickly.
Threshold – The level where sound goes through once the gate opens.
Hold – Allows the gate to remain in an open state once the signal level is below the threshold.

Conclusion

Regardless of your studio setup, background noise will always be there. With these tips and the best mic isolation shield, you’ll have full control over your recording sessions.

Clean mic signals will add professionalism to your sound, giving you the best sound quality possible!