A microphone pop filter, commonly known as “that thing in front of the mic,” could be the difference between getting a perfect vocal take or taking it again from the top.
In this blog, we’ll explain what a mic pop filter is, what it does and identify what qualities make the best pop filter so you can spend your studio time creatively, rather than editing out all those popping sounds.
WHAT IS A MICROPHONE POP FILTER?
A mic pop filter—not to be confused with a foam windscreen, which we’ll talk about below—is a thin piece of nylon stretched taut within a circular frame and mounted in front of a microphone to silence the popping of “P” and “B” sounds.
Without a pop filter, these explosive consonant sounds, which we call “plosives,” can introduce unwanted distortion or mechanical pops that listeners find distracting.
A plosive is a consonant sound produced by the build-up and sudden release of air pressure within the vocal tract. In English, the basic plosives are “P,” “B,” “T,” “K,” “D” and “G.” When singers form a plosive, the resulting burst of air strikes the microphone diaphragm like a drum, sending a small electrical current down the cable that we hear as a pop.
MIC TECHNIQUES TO AVOID POPPING
Before we reach for the pop filter, let’s explore some alternative solutions to eliminate unwanted pops.
1. Sing off-axis. When you sing directly into the front of a microphone, perpendicular with the capsule, you’re “on-axis.” Off-axis is any position other than a 90-degree angle. Try rotating the microphone or taking a step to the side in order to avoid a head-on collision between the vocalist’s air column and your condenser mic. However, in a live multitrack setting where polar patterns matter and bleed-thru from other instruments is a concern, singing off-axis might not be the best way to go. But it works great for overdubs!
2. Smile while you sing. Smiling lifts the corners of your mouth, tightening the lips and jaw so that you get a controlled air column that’s less likely to need a pop filter. Try singing a phrase like “peanut butter” into the mic and notice the difference between tight, smiling lips and floppy, plosive, popping lips.
3. Borrow a pencil. If you record a lot of singers or voiceovers, a trusty schoolyard special #2 pencil could become your most valued piece of gear. If a singer with stage experience is struggling in the studio, asking them to hold a pencil to their lips as they sing prevents pops by disrupting the air column. And it helps with mic technique, as many live performers are more comfortable using handheld mics rather than a condenser mic on a stand with a pop filter. Instruct the vocalist to “sing into the pencil” and position the mic where it sounds best.
HOW TO ATTACH AND USE A POP FILTER TO RECORD VOCALS
If you’ve tried the above mic techniques and still find yourself deleting popping noises, go ahead and order that pop filter. If you’re crafty, you can improvise a DIY pop filter by stretching a pair of tights around a wire hanger, embroidery hoop, empty tomato soup can, or anything else that resembles a frame.
To attach a pop filter to a mic stand, start by positioning it so the gooseneck reaches the mic clip or shockmount. Tighten the clamp until the filter is mounted securely to the mic stand. If your mic stand is wobbly, reposition the pop filter to balance the weight or use sandbags to weigh down the base of the stand.
Once attached, position the gooseneck so the pop filter rests 3-4 inches in front of the microphone. Keeping a few extra inches of space between the vocalist and the microphone reduces lowend buildup and encourages good mic technique.
POP FILTERS VS. WINDSCREENS
Musicians who have played an outdoor gig or two are likely familiar with the famous neon foam mic sock. They pop up (pun absolutely intended) on vocal mics and drum overheads at big music festivals to cut down on the wind noise, but believe it or not, they are not pop filters.
Imagine the background noise when local TV news covers a weather event. That’s primetime for windscreens. They’re designed to reduce the sound of continuous wind—the kind that causes feedback and messes with your signal-to-noise ratio, not the short, intense bursts of air that accompany plosives in the recording studio.
Windscreens are best in live, outdoor settings where condenser mics are equally likely to capture the howling wind as the ride cymbal. In the studio, pop filters are your friend. But don’t underestimate the #2 pencil.
Check out our Music blog for more recording advice and mic placement tips!