Solid protection from wind blasts and 'plosives for your side-address microphones
By Phil O'Keefe
Arizona-based Olsen Audio makes a wide variety of different microphone accessories under their WindTech brand, including fur and foam windscreens in various sizes, nylon screen disc type pop filters and the item under consideration here - the PopGard, a wind and pop filter designed for use with side-address vocal microphones.
Figure 1: The USA built Windtech PopGard is designed to sit on your microphone instead of requiring a separate stand or clamp to hold it in position (Click on images to enlarge)
Close miking has become a common approach to recording singers, but it is not without its drawbacks. One of the most commonly encountered ones is due to wind blasts and vocal "plosives" from B and P consonants. In most cases when using a cardioid vocal microphone within a few inches from a singer's mouth, some sort of pop protection is required in order to prevent objectionable blasts of air from ruining an otherwise excellent take.
Another issue is mouth moisture. Most engineers have worked with "spitters" at one time or another - you know the type; a vocalist that you can watch spittle flying out of their mouth as they sing, even from 20 feet away on the other side of the control room glass. The problem is, all of that moisture can be bad for your microphones, causing accumulation of foreign material on sensitive diaphragms as well as potentially temporarily shorting out condenser microphone capsules, bringing your vocal tracking session to an abrupt halt.
Bearing a superficial resemblance to the clamp-on arched metal blast filters used by Abbey Road studios on their U47 and U48 microphones during the Beatles era, the arched frame of the PopGard is made out of black nylon instead of metal, and is a bit larger overall and surrounds more of the sides of the microphone than those older units. Two smaller diameter interior arches are lined with rubber and rest against one side of the microphone body and head grille. Attached to the ends of the interior arches is an elastic band, similar to what you'd find on a shockmount. This is stretched over the back side of the microphone grille, holding the unit in place.
The actual wind and pop filter part of the unit consists of a metal screen of a type similar to the fine inner layer mesh used in some microphone head grilles. (Figure 2) The metal is a little finer in thickness than on some of the all-metal disc type pop filters. This inner layer is covered by a micro-mesh type outer layer. The outer layer of mesh on the PopGard was designed to deal with the moisture issue by reducing the amount of spittle from the singer's mouth that reaches the microphone's capsule. The mesh is extremely fine in weave, to the point where it looks rather like semi-transparent silk, but while it feels soft to the touch, it also seems to be much tougher and stronger than silk. Best of all, it is hydrophobic - it stops moisture from easily passing through. This is especially helpful when using condenser microphones, since too much moisture can cause sonic problems and can even cause the microphone to short out; bringing your session to a halt until the capsule dries. Spit particles and dust can also build up on your diaphragm and can affect its response and sound. The hydrophobic filtering of the outer mesh layer keeps you microphones dry, even with very heavy "spitters." It can also be easily cleaned - a fact that WindTech mentions on the packaging, but doesn't tell you how to do. In between singers, I found removing it from the mic and giving it a quick wipe down with a soft cloth dampened with Lysol spray helped keep it fresh, clean, and sanitary. For deeper cleanings, the elastic band can be removed and the unit washed in lukewarm soapy water, then rinsed and patted dry with a soft cloth.
Figure 2: The rear of the PopGard, showing the interior metal mesh layer, rubber-lined mounting arches and elastic band
The PopGard is designed to work with side address microphones that are from 1.8" to 2.7" (46 - 68mm) in diameter. This includes a wide range of side address vocal microphones. Unfortunately, some side-address models will be too large, and a very few may even be too small to work with it. For example, the PopGard is too small to fit over a RCA 74b ribbon mic, and of course, the design totally prevents it from being useful with end-address microphones such as the E/V RE20, Shure SM7b and Heil PR40, so voiceover artists and singers who use one of these (or any similar end-address microphone) will have to seek a different solution to their plosive and pop problems.
From the manufacturer's photos, I felt confident that the unit would easily mount to cylindrically shaped microphones that fall within the diameter range, such as the Rode NTK and Soundelux ELUX 251 (Figure 3), but I wasn't sure how it would do with more rectangular-shaped grills such as those on the AKG C-414, or cone-shaped and "slanted" head grilles such as those found on the Neumann U87 and Mojave Audio MA-300. Fortunately, the very light weight of the unit and the stability of the design holds it in place, even with rectangular, angled and non-cylindrical grilles. (Figure 4)
Figure 3: The PopGard's design is ideally suited to cylindrically shaped microphones, such as this Soundelux ELUX 251
Figure 4: Surprisingly, the PopGard also works well with most cone or sloped head grille designs too, as seen with this Mojave Audio MA-300
Because the PopGard mounts directly to the microphone, there is no need to adjust a second stand each time you reposition the vocal microphone - the pop filter moves with the mic, making transitions between singers faster in the studio, while reducing the clutter of a second stand.
Sonically, I found the PopGard to be effective at greatly diminishing plosives and wind blasts. The rubber of the mounting arches and the elastic band do a good job at isolating the screen from the microphone body, reducing the transfer of sound from the wind screen to the microphone via direct mechanical coupling. As with nearly any filter, if you throw enough level and wind velocity and force at it from a close enough distance, some audible effect of the wind is likely to show up on your recording, but in most real world situations, the PopGard does its job quite effectively and transparently, with no appreciable negative effect on the frequency response or overall sound.
Overall, I really like the PopGard. While it is limited to use with side-address microphones, the vast majority of commonly used side-address condenser vocal mikes fall within the size range and will work with it just fine. The elastic is user-replaceable, and as a thoughtful bonus, the package includes one spare band so you're not out of luck if it happens to break - even if it happens in the middle of the night. The design is effective at reducing plosives and wind blasts and also helps keep moisture away from the capsule, which could help your microphones sound better for longer, and can help prevent moisture related capsule short-outs. The hydrophobic material is so effective and useful that I'd love to see WindTech come out with a disc type pop-guard that utilized it. They do currently make a disc style pop filter, but it uses a more traditional nylon screen design. While the design of the PopGard has many advantages (such as the ability to move "with the mic", and not require the use and adjustment of a second stand or external clamp), the design will not "fit" on all microphones, and it would be nice to have this technology available in a format that can be used with virtually any microphone. However, if you're using a side address microphone with the correct dimensions, the current PopGard is definitely a useful and viable tool for protecting both your microphones and your tracks, and is well worth the reasonable asking price.
Phil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Associate Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.