Do I really Need a Pop Filter?
I am of the opinion that a pop filter is an essential tool for getting good sound from a mic in most situations. When I use the term "pop-filter" I include all devices designed to minimize or eliminate plosives from the sound generated by the microphone. A plosive is a quick rush of air generated by the movement of a performer's mouth, in most instances, but this can also occur when a mic is placed close to a loudspeaker or its grill cloth. For a vocalist, plosives are created by certain hard consonants such as "b," "p," or "t."
I am sure most reasonably astute mic users know that most microphones already come with some type of minimal pop filter. These are intended to minimize plosives and to minimize spittle from reaching the diaphragm of the mic. The well-known Shure SM58, for example, has a thin layer of foam inside a wire cup or ball. Both the wire mesh and the foam sheet are intended to minimize the effect of plosives and spittle. This mic, however is notorius for the plosives it creates. I personally would never use an SM58 or a Beta58 without a foam cover over the wire mesh screen. A good example is in a demo of four Shure mics by Mitch Gallagher in May 2021. Start at 3:40 and listen for the sibilance with each of these uncovered mics. Another good example of proximity effect and plosives is a comparison of the Shure SM58 with the Beta58A -
To the right is a good video by James Attaway on How to Hold a Microphone. I believe he is using a cardioid condenser mic (Shure SM86) in these demonstrations. He has some good suggestions and a good demo of the problem with cupping the mic, but he disregards the importance of using a pop filter. Be sure to note the plosives throughout the video due to his using an uncovered mic. Pay attention to this during the first two minutes. The plosives are present even though he holds the mic under his mouth, not directly in front if it. Notice how plosives come into play as he talks about keeping the mic in front of the mouth and demonstrating the proximity effect. At that point, almost every word he says contains plosive sounds, not just those with "hard" consonants or sibilance. In some places you can hear "clicking" mouth sounds.
This particular condenser mic may be somewhat more sensitive to plosives than a dynamic mic, but plosives do occur regularly with uncovered dynamic mics, such as the SM58. Part of Jim's issue is that he prefers a somewhat "bassier" sound for his voice, even though it is not his natural sound. I do not deny the advantage or desirability of this warmer sound - it may be one reason why some vocalists like the SM58, but one should understand what is happening. It is amazing to me that someone who has such technical expertise seems to ignore the detrimental effects of plosives, and many singers and audio techs have fallen to the somewhat misguided advice of people like the engineers at Shure to "sing into the mic." Notice that during most of his presentation, James does not speak directly into the mic – he keeps it below his mouth most of the time. He does discuss the reasons why it may be important to be close to the mic and why with a directional mic, one should have the mic pointing toward the mouth. In closing, he says "you cannot make it sound better than what …. is captured by the microphone." I agree, and I emphasize that plosives are not part of the natural sound of a voice. Once they are present, you will not be able to remove them. My recommendation is that one should always use a pop filter or screen or both with vocals and instruments such as horns that create moving air as well as sound.
In 2022, Chris Liepe published a video that gives interesting details and suggestions for using pop filters. He calls them "popper stoppers," perhaps to indicate that they deal with a really important problem. This video runs almost 12 minutes, and he tries to deal objectively with the issue, recognizing that some engineers are convinced that pop filters significantly degrade the sound a mic picks up. One thing I found interesting is that he doesn't like pop filters because he doesn't like things in front of his face. So his negative opinion has nothing to do with the technical reason for using one. I have experienced similar responses from other artists and speakers. He mentions techniques such as singing or speaking off-axis, but depending on the mic, this can "color" the sound. If good quality sound is the issue, some type of pop filter should be used. He does mention that pop filters can dull the sound, and many performers think this is the case, but I have never seen an effective demonstration of this. It is an opinion not backed up by fact in most cases. The tests Chris does seems to demonstrate the opposite!
Joe Crow has an interesting page on pop filters, or pop shields. He has two brief audio tracks that demonstrate how a pop filter removes plosives. He suggests ways of minimizing plosives without using a pop filter, and these should be used if one has personal objections to the use of a filter. He makes note of the built-in "windscreen" of the Shure SM58, but he errs a bit in saying that this will "block out plosives." It is not entirely effective in reducing plosives. The mic needs an external foam pop filter.
He also mentions a third type of filter called a windscreen., which is used to minimize the effect of wind blowing across the screen and diaphragm that creates a significant rushing sound. When a mic is used outdoors, some type of windscreen is usually essential.
Edward Smith has a helpful page on pop filters, but he mistakenly states that a pop filter "Can suffer from the proximity effect." The proximity effect has nothing to do with the pop filter - it is due strictly to the microphone design. A pop filter makes it possible for a vocalist to work closer to a mic without plosives, and this closeness is what causes the mic to generate the proximity effect. One video has a very good demonstration of how a pop shield minimizes plosives and the relative performance of different designs. He concludes with this statement: Pop filters are excellent for indoor use to diminish plosives and sibilance when using voice over microphones. Without one, your audio can sound abrasive and amateurish. They’re essential for doing high-quality voiceovers, podcasts and YouTube videos that keep your listeners engaged.
Lewitt Audio has an excellent page about pop filters that tells why they are used and discusses different type of filters. The author also emphasizes the need for a shock mount with a mic that has good low-frequency response, such as a condenser. One particular mic made by Lewitt is the L440 Pure, shown to the right, which is a large diaphragm condenser designed to minimize cost. It sells for less than $300.
It and its siblings have a special two-layer screen design that has two wire layers with different hole sizes. This design protects the mic element and reduces plosives. The L440 comes with a custom pop screen that attaches magnetically to the included shock mount for further reduction of plosives. The picture to the right shows this pop screen in place on the L440.
These design details demonstrate the fact that plosive are a significant problem that needs to be dealt with effectively in professional settings.