I am a jazz singer in my spare time, and have been talking mics with various musicians. There is a sharp division between those that think the foam “clown nose” on a mic is a good idea or a bad idea.
I perused several Internet forums and there are endless discussions of what people think and feel it does to audio quality, and how well it stifles sibilance (the “essss” sound) and plosives (the popping sound of B, G, T, and P consonants). Some simply don’t like the appearance with the foam cover. Others feel it is important for keeping spittle out of the mic, especially if it is used by other singers. Much easier to clean the foam cover than get crud out of the mic itself. And keeping the foam clean is stressed, since a dirty cover will stifle sound quality.
Some feel it ruins the sound entirely, some feel it cuts off too much of the high end, some say it cuts of just a tiny bit of the high end while doing a great job of making the singer sound like he or she isn’t using a mic.
Lots and lots of theory and emotion are bounced around, but even when they talk about testing the differences, I don’t see them published. So I decided to do my own tests by recording the mic with and without foam, singing, purposefully using plosives and sibilance, and then speaking normally. I don’t have the equipment to do graphs of frequencies, so my tests were subjective. And that is ok. I was not going in with preconceived notions of what it will do besides reducing “wind” sounds. And cutting off a tiny bit of the high end is intentional when using the foam, since that is where sibilance happens.
I recorded a variety of my singing and speaking using Audacity, comparing similar lines with and without the foam cover. I also varied the distance from the mic and the amount of gain on the mixer. I’m comparing my mic with a friend’s mic I have used previously.
I’ll tell you right up front that it depends on the microphone. I’ve used a few different mics, and own a Heil PR-35, a dynamic mic with a large diaphragm. I have a friend who uses the Shure Beta 58a for doing regular gigs. On her mic, I sound really clear with no foam cover, and the sibilance and plosives are minimal even when I’m up on the mic where the richness of my voice comes through the best.
On my mic (Heil) with no foam cover, I have to carefully control my speech to avoid over-popping P’s, and the sibilance is easy to hear (a common complaint with the sensitivity of this mic). However, when I add the foam cover to my mic, most of those issues disappear. I do lose some volume which can be easily adjusted on the mixer. But unless I were switching back and forth between foam and no-foam, that wouldn’t be an issue. I would simply do the mic check with the foam on and go from there. I didn’t really notice a quality of sound change except at the far high end. Another thing I noticed was that my mic picks up more volume by the nature of the larger diaphragm size, so I also had to adjust the volume down on the mixer to compensate for the difference between the two mics.
Some forums advise backing away from the mic overall to control plosives, and cranking the gain to compensate. I found that this led to a more tinny sound unless I was doing full-voiced singing (and I’m often doing much more intimate singing styles). I did comparisons of foam and no-foam at 8-10 inches and found that plosives were still an issue with no-foam.
I found that being right up near the Heil PR-35 WITH the foam cover yields the best result with the this mic. I have to keep the gain on the mic down because I’m so close to the mic, but I get a richer sounding bass quality when I’m up close. But again, that is with THIS mic. With the Shure, I didn’t need a foam cover for sibilance and plosives. The EQ can also be adjusted a bit to add in more mid and high range if you feel the sound quality has changed.
I still need to do a test between the two mics to hear which I like better with my voice. And that is the best approach to buying a mic for yourself. Test them at a local music store doing the style of singing you do. Some mics pick up bass better, but if you are a soprano, you are more interested in a clear high range. Having a good matching mic is one of the most profound changes you can make to your singing, as is a quality sound system (and knowing what the knobs do to your sound).
FOLLOW-UP: Doing some side-by-side comparison, my friend said the foam made my voice sound muddy compared to no foam, so we removed the foam, adjusted the mic gain down, and it sounded fine with my lips about 3-inches from the mic.