Friday, 2 October 2015

How to Eliminate Plosives in Your Audio Recording

Plosives can make your recording sound amateurish if afflicted with that horrid explosive sound every time a harsh consonant is expressed. A plosive is a small explosive sound when a narrator expresses Ps, Bs, or any word that requires a little blast of air. The mic sounds like it is recoiling in anguish at the sudden detonation from the lips. Here are some quick tips on how to get rid of plosives in your audio recording.

What is a Pop Filter?

What a Plosive Looks Like
Peter Piper picked a peck of pickled peppers, a peck of pickled peppers Peter Piper picked... Yes we know the rhyme, but takes added significance when testing the recording for plosives. Take a look at a plosive on the waveform and it will have the appearance of a long hook.

What can be done to get rid of plosives?

Firstly, you can get a pop filter. A pop filter is tightly-woven mesh stretched over a hoop and placed in front of a mic. Do not go cheap and make one yourself. I tried stretching a pair of tights over a coat hanger, and it is not as good as a proper pop filter. The Rode comes complete with a studio standard pop filter that has two layers, stretched tightly over a frame. It also sits nicely in front of the mic and breaks up the air that explodes from the mouth. A pop filter also protects the mic from moisture from the breath and the force of the words themselves.

A sample of my audio book The Shuttered Room

Placement of the Voice over the Mic

Don’t stand too close to the mic when audio narrating, unless to achieve a particular effect. I will place the mic at least ten inches away and place it slightly to one side of the mouth, so that my breaths will not hit the mic directly. Audio book narration is often in mono, so the recording should not be affected.

How to Erase Plosives from your Recording

Plosive Correction on Equalizer
You can eliminate the odd plosive that gets onto your recording by equalizing them out. You can easily do this by going onto the equalization of whatever recording software you are using. The example I am using here is Audacity, free sound editing software. Click on ‘effects’ and then on ‘equalization.’

When the equalization grid comes up, decrease the lower frequencies in a gradual way, leaving the higher frequencies in a flat line. The result will be a sort of sloping plateau as shown on the image. You can save the setting under ‘manage curves’ and call it something, such as ‘plosive elimination’ to save having to adjust the frequencies again every time you want to eradicate plosives.

Before and After Equalization: the Hooked Plosive has Gone
Highlight the section of recording that contains the plosive and then press OK. You will notice the hooked shape of the plosive will flatten out. Play the recording back and there will a subtle but definite difference in sound. The explosive sound has gone.

Plosive Correction

Sometimes, a mic can be at fault. My first mic recorded plosives from the gentlest consonants, no matter what I did. Needless to say, I exchanged my mic for the Rode and the problem was solved. The lesson here is, don’t go cheap on the mic. Get the best you can afford and the niggles such as plosives will no longer be a problem in your recordings.

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