The proximity effect in audio is a phenomenon that comes up a lot in audio production. It’s mostly a problem with vocalists like singers, podcasters, YouTubers, and streamers. If you’re not careful, it can be a big distraction during your recordings.
We’ll show you some easy ways to reduce proximity effect and stop it at the source. But to do that, we need to understand what causes it in the first place.
What Is the Proximity Effect and What Causes It?
The proximity effect happens when a sound source gets close to a directional microphone. As it gets closer, bass frequencies become exaggerated. In some cases, there’s unwanted distortion.
It’s caused by pressure differences on the front and back sides of the microphone’s diaphragm. Because of this, it’s only an issue with directional microphones such as cardioid or figure-8 mics.
- Read more: Microphone Polar Patterns Explained
Why the proximity effect only works on directional microphones
Directional mics work by allowing pressure on both sides of the diaphragm. Those pressure differences cause the diaphragm to move, thus creating an electrical signal.
Here’s a diagram to help illustrate:
Naturally, there’s a slight delay with the back-entering sound wave. When that happens, the phase and amplitude are slightly off from each other. This produces a clean-sounding signal.
When the sound source gets closer to the mic, the front- and back-reaching sound waves start opposing each other more strongly. As a result, the conflicting phases and amplitudes cause low-end frequencies to become exaggerated.
Why doesn’t the proximity effect happen with omnidirectional mics?
Omnidirectional microphones don’t have that second opening to the diaphragm’s backside. Instead, there’s an internal chamber with a fixed amount of pressure. Since there aren’t conflicting sound waves on the front and back, the proximity effect doesn’t occur.
Is Proximity Effect Bad?
That depends on how you use it:
- How it’s good: In some situations, it can be used as a creative tool that enhances your performance. DJs, singers, and talk show personalities often use it to get a phat, sexy-sounding voice. With other instruments, the proximity effect can be used to add extra warmth and body to their sound.
- How it’s bad: Excess bass frequencies can make some vocals too unintelligible. Other instruments that have been “fattened up” can also sound muddy. As a result, they unintentionally compete with other low-frequency sounds like a bass or kick drum.
Proximity effect is more common with sound sources that produce low-end frequencies. For example, male vocalists will come across it more often than female vocalists. Other instruments can also cause it, like guitars, basses, keyboards, horns, and cellos.
5 Ways to Reduce the Proximity Effect
There are some ways to combat the proximity effect while recording and mixing. Here are a few quick tips to reduce it:
1. Don’t get so close to the microphone!
This sounds really obvious — and it is. But since the proximity effect is caused by getting too close to the microphone, the first thing to try is moving away from it.
If you’re the audio engineer working with a vocalist, try coaching them about proper mic positioning.
2. Change the angle of the microphone
Another simple way you can reduce proximity effect is by changing the microphone’s angle. As the mic angle changes, the diaphragm’s sensitivity also changes.
It’ll still pick up sound waves from both the front and back ports. But since they’re coming in at an angle, the sound waves won’t directly oppose each other to create the effect.
3. Use a pop filter
Another way to eliminate the problem is by placing a pop filter outside the effect zone. By putting a physical barrier between the performer and the microphone, you ensure that the proximity effect won’t be a problem.
A super simple pop filter. It has a bendable arm and attaches to any microphone stand.
4. Use the microphone’s built-in EQ settings
Some microphones, like the Shure SM7B or the Audio Technica AT2035, have a switchable roll-off. This switch reduces how much low-end it picks up. It’s a handy feature made specifically to combat proximity effect.
That said, most other microphones don’t have this feature. But, many of them are engineered with a natural roll-off in their frequency response, such as the Shure SM58.
5. Use a high-pass filter
Up until now, all the other tips were about stopping proximity effect at the source.
But say that your tracks have already been recorded and you still hear it. What do you do at this point?
One simple way to mitigate it is by using a high-pass filter in your EQ settings. Use it to clear out the low end, hopefully doing away with some of the muddiness in the process.
