Microphone pops from vocal plosives (aka stop consonants) sound terrible (in every situation but beatboxing). Whether you’re presenting live, singing in a studio, or speaking in a broadcast setting, plosives should be avoided and eliminated at all costs.
Here are the top 10 tips for eliminating microphone pops and plosives:
- Use a pop filter
- Distance yourself from the microphone
- Tilt the microphone slightly off-axis
- Use an omnidirectional microphone
- Place your finger or a pencil against your lips
- Engage the microphone’s high-pass filter
- Engage the mic preamp’s high-pass filter
- Fix with equalization
- Fix with software
- Alter the vocal delivery
This article will explain each of the 10 ways to reduce and eliminate microphone vocal plosives in more detail. But first, let’s discuss what vocal plosives are:
What Are Vocal Plosives And How Do They Affect Microphones?
What are plosives and how do they affect microphones? Plosives are strong blasts of wind energy that come from the mouth of a speaker. Plosives happen on certain consonant sound when a part of the mouth gets closed (lips, tongue and teeth, or the back of mouth).
In English, plosives happen on the following 6 hard consonant sound:
- P: from the lips
- B: from the lips
- T: from the tip of the tongue and teeth/palate
- D: from the tip of the tongue and the teeth/palate
- K: from the mid tongue and the back of the mouth
- G: from the mid tongue and the start of the throat
If you’re an English speaker, try making the consonant sounds mentioned above and notice how a part of your mouth/vocal tract actually closes and opens as you make the sounds.
As the mouth/vocal tract closes and opens during speech, tiny “blasts” or air are suddenly created. These “blasts” are called plosives.
Though plosives are relatively weak, they often hit microphone diaphragms with such force that they overload the mic capsule/element. This, in turn, produces largely unwanted “pops” in the mic signal.
Let’s get into the 10 ways to eliminate these unwanted pops we call “microphone plosives.”
1. Use A Pop Filter
Placing a pop filter between the speaker/vocalist and the microphone will dissipate plosive energy from the speaker’s voice before that energy hits the microphone diaphragm.
Pop filters are typically made of metal or nylon mesh and act as a plosive shield for microphones.
Placing a pop filter several inches from the microphone and between the mic and vocalist will help tremendously in reducing the chances of plosive pops in the mic signal. This is often the best method of reducing pops.
To test the distance of the pop filter, try holding your hand behind the pop filter while you blow or make plosive sounds toward it (the “Pa-Pa-Pa” method is effective). Distance your hand from the filter until you can barely feel the plosive energy. This is likely the best mic-to-pop-filter distance for you.
For more information on microphone pop filters, check out my following articles:
What Is A Microphone Pop Filter And When Should You Use One?
Best Microphone Pop Filters
2. Distance Yourself From The Microphone
Distancing yourself from the microphone causes the sound waves from your mouth to travel further to reach the microphone. This extra distance reduces the intensities of both the sound wave and of the plosive energy. Weaker plosive energy will reduce and often eliminate plosive pops in a mic signal.
Air is a medium. Energy travelling through this medium is subjected to friction and dissipation. This is true of both sound waves and vocal plosives.
A plosive energy “blasts” travel outward from the mouth, they decrease in intensity until they’re completely dissipated. The rate of intensity loss is actually quite fast.
Therefore, distancing your self even a few inches from a microphone can greatly reduce or even eliminate the vocal plosives that produce mic pops.
To test this, you can use the same blowing/plosive test mentioned above. Make plosive sounds toward your hand until you feel that the energy is adequately dissipated. This distance is likely a great starting point for the microphone position.
3. Tilt The Microphone Slightly Off-Axis
By tilting the microphone slightly off-axis, the plosive energy does not hit the diaphragm head-on/perpendicularly and has much less of an overloading effect on the diaphragm.
This is a common studio trick that I’ve been using since I began in the recording/broadcast industry.
Typically I’ll keep the microphone’s “on-axis” pointing to the centre line of the talent’s body so that they naturally feel they’re talking directly into the mic. However, I’ll point the mic below the mouth, somewhere around or below the chin. This makes for a natural-feeling mic position while also tilting the microphone off-axis to reduce/eliminate plosives.
When plosive energy is directed toward an “off-axis” diaphragm, the blast hits different parts of the diaphragm’s area at various times. This is what reduces the impact and the probability of overloading the microphone.
Note that with directional microphones, you do not want to tilt the mic too far off-axis or else the mic will start to sound unnatural. Check out the polar pattern diagram on your particular mic spec sheet for more information on how off-axis sounds will be coloured.
Here is an example of a polar response graph from the Neumann M 50:
4. Place Your Finger Or A Pencil Against Your Lips
Placing your finger or a pencil against your lips is similar to using a pop filter by means of dissipating plosive energy before it reaches the microphone diaphragm. This method immediately disperses much of the plosive energy released by your mouth, diverting it away from the mic diaphragm.
This may seem silly, but it has tremendous impact on reducing plosives in the microphone. I’ve found this technique particularly useful when recording long format voice-overs or voice acting. When the talent and microphone haven’t changed positions or tonalities, but there’s a particularly nasty plosive, it’s often better to try the pencil trick rather than reconfiguring the mic/talent.
5. Consider Using An Omnidirectional Microphone
Omnidirectional microphones work on the pressure principle which means that all sound only hits one side of their diaphragms. It is practically impossible to overload an omnidirectional microphone with plosive energy because it’s very hard to push the diaphragm that far back with a constant pressure on the other side.
Plosives happen when a diaphragm is “mechanically overloaded” (when the diaphragm hits against the housing of the capsule.
When both sides of a mic diaphragm are open to external sound pressure, we have some sort of directional microphone. As plosive energy hits the front of the diaphragm, the rear of the diaphragm could likely be at a lower pressure than atmosphere, furthering the movement caused by the plosive energy. This is a recipe for popping a mic.
Omnidirectional microphones generally avoid this occurrence due to the constant pressure on the rear of their diaphragms.
Typically, large diaphragm mics (unlike the aforementioned Neumann KM 183) are preferred for vocals. Fortunately, many high-end large-diaphragm condensers are multi-pattern (such as the featured AKG C414 XLII). When using these microphones, reducing plosives could be as easy as flipping a switch on the microphone to engage the omnidirectional mode!
Note that omnidirectional mics provide much less gain-before-feedback and are much more sensitive to environmental sounds around it.
When capturing voice, omnidirectional mics may work excellently in soundproof vocal booths. However, in live reinforcement or less-than-ideal recording environments, omnidirectional microphones may be too sensitive for the job.
6. Engage The Microphone’s High-Pass Filter If It Has One
Plosive energy is fairly low-frequency energy. Engaging a microphone’s high-pass filter (HPF) will often rid of the offending plosive frequencies.
Some microphones have built-in high-pass filters to help combat the effects of the proximity effect and to help reduce low-end rumble. These HPFs can also be a saving grace for reducing and eliminating plosive pops in a mic signal.
The aforementioned AKG C414 XLII has several HPF options @ 40, 80, and 160 Hz.
Much of the vocal plosive frequency information will be under 150 Hz. Oftentimes a HPF set around 100 Hz or 150 Hz will effectively rid of the offending plosive frequencies without overly thinning out the sound of the voice.
For more information on microphone high-pass filters, check out my article What Is A Microphone High-Pass Filter And Why Use One?
7. Engage The Mic Preamplifier’s High-Pass Filter If It Has One
If a microphone does not have a high-pass filter (many don’t), engaging a post-mic HPF will also help to reduce/eliminate plosives from the mic signal. Many mic preamps come with built-in HPFs you can choose to use.
Again, engaging a HPF around 100-150 Hz should help reduce or eliminate the plosive energy in a mic signal without removing too much low-end from the mic signal.
The ART TubeOpto Mic Preamp (pictured below) is a great example of a mic preamp with built-in high-pass filters.
As always, trust your ears to ensure you aren’t removing too much of the low-end from a voice.
8. Fix With Equalization
This is similar to using high-pass filters. If you have an equalizer in your signal chain or in your digital audio workstation, you can track through it with the offending plosive frequencies attenuated or completely filtered out.
Equalizers (particularly parametric EQs) are much more flexible than simple high-pass filters. With equalization, we are able to get a bit more surgical with how we deal with the offending plosive frequencies.
It is, of course, best to get a plosive-free recording at the microphone, but EQ will be a good tool to use in case plosives become a nuisance in the mic signal.
EQ can be applied via a standalone in-line audio device, or via software, which brings us to our next point.
9. Fix With Software
If the above techniques did you no good or you’ve received a poorly recorded voice track to work on in post production/mixing, it is possible to fix microphone plosives with software.
It’s always best to record voice (and everything else) correctly at the source. However, reality doesn’t always pan out like that and often times you’ll need to fix plosives in the mix.
Notable plosive reducing software plug-ins:
- ERA Plosive Remover
- iZotope RX De-Plosive
10. Alter The Vocal Delivery
As a last stitch effort, altering the vocal delivery could work. This is more of a joke than a serious tip, though it could certainly work. I just wouldn’t suggest rewriting a script to remove all the p’s and b’s, for example!
How do I fix a popping and crackling microphone? A popping and crackling mic is typically fixable by addressing the connection issue. Most often, it has to do with replacing a connector/cable. If the issue is not the cable, it is likely the microphone’s output connector or inner connections unless it is the load connection (mic preamp input, etc.)
Why does my wireless microphone keep cutting out? Wireless microphones typically cut out when there’s an interruption in the wireless signal. This could be caused by radio interference or if there’s too great a distance or barrier between the transmitter and receiver.