At some point we’ve all watched a music video showing a singer – eyes scrunched shut, hands usually clamped over their headphones – singing dramatically directly into a microphone. Or at least, they would be, if the mic wasn’t kept away from their face by a seemingly random piece of mesh, separating mouth from mic.
This is a pop filter, and while it may look bizarre, there’s actually a good reason for their existence. A pop filter is a simple device that ensures you record top-notch sound, and it works just as well for an ordinary podcaster as it does for a Grammy Award-winner singing their lungs out in a professional studio.
What does a pop filter do?
Its purpose is fairly basic: a pop filter is simply a mesh screen that prevents harsh, unpleasant noises from hitting your mic. The thin film of Nylon that most pop filters use isn’t thick enough to muffle speech, but it does smooth your voice out a little, taking the edge off sounds that can saturate the sensitive equipment in your mic.
This is important even if you’re not recording conversations at particularly high volumes. When we speak, our mouths expel air at varying levels of pressure and speed, and certain sounds – for example, the “p” in “pop” – can create a popping noise as the air leaves your lungs. This little wave of air pressure hits your mic and can make the diaphragm inside it move slightly, thus interrupting the sound quality.
The “popping” effect, also known as a “plosive”, occurs more often than you’d think – hard consonants such as 'b', 'd', 'g', 'k' and 't' can produce them, and some mics really do struggle with their impact.
A pop filter, when positioned between your lips and the mic, negates the impact of these plosives. Covered in acoustically semi-transparent material – usually Nylon, but not always – it cleverly disperses the air coming from your mouth, filtering it into smaller bursts that don’t overwhelm the mic and keep the audio clear.
Should I use a pop filter?
Ensuring you get the best audio performance is the most important use for a pop filter. But it also serves another purpose; when the average person speaks or sings, they don’t just expel air – they also expel small amounts of saliva. If you’re sitting at an expensive mic all day without a pop filter to protect it, you’re basically covering it in your own fluids. After a while, it can even start to smell of stale saliva.
As if that wasn’t enough, human saliva also contains salts, which can eventually start to corrode and damage a mic. So anything that can stop this from happening is a bonus – and it’s a lot easier to clean or replace a pop filter than it is to drop your entire mic into the dishwasher.
How do you position a pop filter?
Some microphones and shock mounts (which suspend the mic in an elastic cradle to prevent unwanted noises if you knock into it) come with pop filter built into their construction, but the most common type you’ll find feature a simple screw mount to clip onto a mic stand or arm. One thing to note is that you shouldn’t attach the filter to the mic itself, as you’ll be undoing all its good work when vibrations travel from it and straight into the mic.
The ideal distance between the mic, the filter and your mouth varies according to who you ask. It’s probably best to experiment a little to see what works for you. It’s mostly logic: if you’re loud, you can move it further from the mic towards you. If you’re quiet, it should be positioned nearer to the mic so it can still pick up your speech. The most important thing is to ensure you don’t accidentally bump into it mid-flow, causing it to knock into any other equipment.
Which kind of pop filter do I need?
Because pop filters are fairly simple creations, buying one isn’t that complex. There are two main types: Nylon and metal. A Nylon filter is self-explanatory and usually comes with its own clamp and mounting bracket.
A metal pop filter, meanwhile, substitutes the Nylon with a fine mesh screen. This can be easier to clean and is more hard-wearing than the fabric version, which by necessity can be quite thin and fragile. However, these ones can be a little small, which could be a problem if you tend to move around a lot as you speak. Nylon filters can be picked up online for as little as £5, while metal versions tend to start at around £10.
One thing to keep in mind is that you may not need a pop filter at all. Using one with a condenser microphone is recommended – but if you have a vocal dynamic mic, the pop filter is actually already built into it. Using a filter in addition to the one that’s already there will wind up muffling your audio.