Pop Filters: Which Work? Which Suck? The Lowdown
First, I agree with comments made on another forum: if you can avoid a physical barrier between a vocalist and a sensitive condenser microphone, avoid it. Physics dictate that any barrier to acoustic waves comes with audible side effects. But sometimes there is no choice and the sacrifice has to be made. How much of a detriment is a pop filter to integrity of sound or pop protection of the mic' capsule?
The choices and their trade-offs:
Steadman-type corrugated single metal screen with holes
Advantage: good transparency.
Disadvantage: spit protection is minimal (encountering capsule contamination, I can often tell when a Steadman was used).
Another beef: the metal plate resonates and rings. Ping it with your knuckle and you will notice it. I found the distinct resonance frequency will accentuate certain notes
Hakan and similar open-cell foam screens
Advantage: acceptable level of pop protection with minimal, but still audible high end and transient loss.
Disadvantage: comb-filtering with audible peaks. My speculation: as the holes in the foam are largely identical in diameter, resonances from standing waves are multiplied and amplified
Pauli and similar dense, double-layer nylon mesh screens
Advantage: near optimal pop protection.
Disadvanage: audible muffling of highs and loss of transients, plus resonances in two areas, due to standing waves: the mesh layers are parallel, and the mounting ring, though perforated, has an endless number of parallel surfaces formed by the flat, hard frame. Its resonance frequency is determined by its diameter
Cheap double-layer nylon screens, home-made or bought
Advantage: good transparency when the stocking material is not too dense; worse, same or better pop protection as all the others, but at low cost.
Disadvantage: some comb filtering, depending on mesh weave and ring diameter, and audible loss of high frequencies
I have not included here any circular or semi-circular pop shields that mount on or next to the mic, like the famous Abbey Road in-house U48 contraptions, or Brauner’s handmade custom pop-cylinders. There are too many to list, but the same principles of physics apply as with any pop screen: a compromise ranging from good transparency to good pop-protection, but never combined in one device.
For my work I keep coming back to a wooden, rather thin, 6” embroidery hoop/crochet ring I bought for 99¢, covered it with two layers of black pantyhose material (yes, black, for emotional attachment!), and mounted on an old plastic mic mount. It’s acoustically quite transparent, and offers reasonable pop-protection at a ridiculously low price.
*I find it most helpful to test any screen directly with (someone else's) mouth-to- (my) ear, rather than through listening via lossy recording and playback:
put your ear where a mic would be, as the vocalist speaks or sings into the screen. Ears are astonishingly revealing and reliable as test instrument!