Pop Filters: Podcasting and YouTube Snake-Oil
Wishful Thinking — Not Science — Sells Podcasting Microphones and Accessories
(First, pop filters reduce plosives for those speaking or singing strongly within inches of a microphone. They have their place; I am not arguing otherwise!)
Neumann is the top brand name in microphones. Because they sell status-rich microphones for $8,000 they can easily sell an accessory that cost $2 to make for 50x the cost — if they put the Neumann name on it. For most people, the pop filter isn’t even worth the $2 it cost to make — but they don’t know that.
The pop filter is a simple device, one of practically no importance in the scheme of things, but which gives us a clear illustration of how human wishful thinking trumps even the most basic science.
[If you’re reading this article for tips on a podcasting mic. Get a $20 dynamic mic, use it properly by keeping it close, but not too close. Don’t speak into its diaphragm directly. Use it in a room with plenty of carpeting and other sound absorbing material. Then even an $8,000 condenser mic won’t make you sound shabby.]
To understand pop filters we need to understand what they do (rather don’t do). First, we need to understand microphones.
There’s a good chance if you’re reading this that you’ve thought, or tried, to start a podcast. You have some equipment you regret buying. If you had a friend in the professional broadcast world they might have recommended a microphone introduced in 1969 and still widely used today, the Electro-Voice EV20.
Or maybe you’d chose the latest updated version of this microphone, introduced around 10 years ago, the EV320
Both mics do virtually the same thing and work in the same way. I’m fairly certain that if your or my life depended on it we couldn’t hear the difference between them.
So why are there two mics from Electro-Voice currently manufactured, one from a 1969 design and the other 2011? How many buy the RE20 because they’re familiar with the mic, who have a positive bias from years in the business? How many compare both mics and, knowing nothing about the history or cost difference, end up preferring the RE20 over the RE320? How many simply buy the lower priced RE320? Or buy it because 320 is greater than 20? Good luck finding the answer to that question.
There are over 1,000 microphones carried by B&H Photo. I didn’t have to read many reviews to come to one that illustrates my points below. This is for a $5 microphone. Bolding is mine.
On digital recorders and mixing consoles, the difference from a good microphone is obvious: the treble suppresses the turbidity of the bass, just like its appearance : very plastic. But when I plug it into the PA system, its performance is perfect, and it sounds better than those good microphones! This surprised me. It can be seen that, good or bad, depends on how you use it. The $5 package also comes with a cable. If necessary, I will buy it again.
Let’s look at another brand, Shure.
If you watched a Joe Rogen video on YouTube you saw this mic, the Shure SM7B. If it weren’t for his show I believe the EV320 would be the microphone most people would associate with YouTube podcasts. (Hopefully someone reading this can explain why the SM7B has become so popular).
In any case, both microphones have a heavy, substantial look! Most of their inside is air.
The Shure SM7B is around $350, which is no surprise when you compare it against the EV320.
I bought an SM7B. It seemed fine. My family wanted to do a podcast around a movie-watching night. I didn’t want to spend 4-times $400 (the mic has dropped in price), or $1,600. So I bought three of these wondering if it would be good enough.
Good enough? I couldn’t hear any difference; rather, I couldn’t hear a “better” difference. As I was to learn, all mics sound a bit difference, but different does not mean better.
I might have kept the SM7B if it wasn’t worse than the $20 mic when it came time to setting the gain, or volume. I’ll try not to get into the weeds. Suffice it to say the mic doesn’t work well if you talk into it more than a few inches away; that is, it’s hard to get a good volume. To address that problem (it’s not really a problem, the mic shouldn’t be used in that way) there is another device most people buy for the SM7B.
As I said, I would get into the weeds explaining why the Cloudlifter is another wish-fulfillment product. The bottom line is people buy the Cloudlifter when they try to get the SM7B to work like condenser mics.
To get away from technical terms like dynamic and condenser microphones, let’s class microphones as these two types: passive and active.
Keep in mind, there is no perfect microphone!
The RE20, RE320 and SM7B are passive microphones. Your voice activates them. The energy in your vocal vibrations creates electrical impulses mumbo-jumbo. This type of microphone was invented around 1877. What’s great about these microphones is the person has full control over how they vocalize into them. That is, with a little experience, they have complete control of their narrative, so to speak.
The drawback (and benefit!) of passive microphones is if the sound isn’t proximate they don’t pick it up. That’s why if you listen to a standup comedian you won’t hear everyone laughing through the speakers (coming from the mic).
I believe I can make these categorical statement — most humans don’t want to stay in one place, 2 inches away from a microphone! One of the reasons you see people wearing headphones on professional podcasts is so they can hear, directly, what happens when they move away from the mic (they become very faint). Think about it, in those small rooms it’s easy to hear what everyone else is saying.
If it weren’t for headphones, audio engineers would have to cattle-prod people who drifted away from their mics. This is where things get fun! Indeed, this was the #1 problem I had recording my family podcast. Wine and beer would show up. Heads would slump on the couch, their voices barely heard. Or they’d press the mic to their lips and blow everyone’s ears out.
All microphones are a slave to the inverse square law. Please don’t stop reading. It’s really VERY simple.
If you start 2 inches away from the mic, and move to 4 inches away, will you end up at HALF the volume. Nope. Wish it was that easy.
What scientists discovered from experimentation, hundreds of years ago, is that if you set you scale at 1 (it can be in inches, centimeters, the length of your toe, doesn’t matter, as long as you can measure in that unit) then the distance from that sound will decrease in YOUR UNITS, or distance, inversed then squared.
This is a “law” of the world around us. One of the reasons we have a raging pandemic, and unabated global warming, is even educated people believe we can make an end-run around these “laws”.
What happens if you measure your volume at both 4 inches and 8 inches. Is 8 inches half the volume (because it is half the distance)? No, you find that 4 inches is 1/16 in intensity and 8 inches is at 1/64th intensity!
How can you get those numbers which your evidence says is true?
You realize you just square them! The inverse square law was not invented by Newton! In a sense, it’s only a calculation trick he invented that could be used to understand, and manipulate, the world of sound (and other things). TOO BAD MOST OF US DON’T TAKE 5 MINUTES TO UNDERSTAND ITS IMPLICATIONS!
If you keep re-reading this, or researching elsewhere, and get to the point you understand it you will probably know more about how microphones work than 90% of the people who use them.
Again. The measurement of distance is NOT a direct measurement of sound intensity!
However, the measurement of distance is a number that you can use to calculate sound intensity by these steps:
- Inversing that number, 1/Distance
- Squaring that number Distance times Distance
- If you measure in the length of your toe, then what you can hear at five toe lengths away, you’ll DISCOVER that it is 25 toes less intense.
What’s important here isn’t the math. What IS important is that if you accept it, and think about it for a few seconds, you will realize IT IS VERY DIFFICULT TO CAPTURE INTIMATE AND NUANCED SOUND!
If you talk 1 inch into your mic, and all is well, but you move 5 inches away (which isn’t much, right) you’re 25x times less audible! Wow! That stinks, right! In our normal lives we don’t worry about how close we are to others; at least not in inches!
“But wait”, you say, “I sit feet away from my computer and I can be heard just fine. Or when I record a video of a party, it’s okay for people to be many feet away.”
Yes, but you aren’t focused on them, but on the room in which those things are said. The sound is so far away it doesn’t matter if they move around.
Those aren’t passive microphones. They are active (condenser) microphones. They are designed to respond to minuscule changes in air pressure/velocity that carry sound waves. When someone speaks into them closely what does it sound like? Shouting. Can they tell the difference between the sound coming from your voice 5 feet away and that from the wall also 5 feet away? Not easily!
Yet when they speak into a passive mic, which only picks up their voice, down to the smallest detail, you enjoy both what they’re saying and HOW they’re saying it. You feel close to them. Everyone who listens to Joe Rogen and his guests feels closer to them than the reporters at the White House who are heard through far away active microphones.
So where do Pop filters come in? Did you think I forgot!
When you make a Paah sound, like in “pop”, a lot of air rushes out of your mouth. That air is very strong and overwhelms the diaphragm in a microphone, especially the active types. Because a singer, or podcaster, wants to record their voice with all the nuance they can capture they don’t want the paah air distorting the electronic sound-capture of the microphone.
Someone with real experience will have to comment here, but my guess is that the best singers seldom use pop filters because they know when to sing off-axis (not directly in front of the mic) when singing what are called plosives.
For singers, or podcast guests, who don’t have a lot of experience with microphones a pop filter is an easy way to remove plosives from the recording. Again, I’m sure some of the best singers use them (they get in the way). The main point is that a pop filter has a very limited function — to prevent fast, strong air from hitting the diaphragm of a microphone.
However, most people use pop filters because they believe they will fix the drawback of active (condenser) microphones — their sensitivity making them susceptible to on-rushing air that wouldn’t affect a passive (dynamic) microphone.
How can I make this claim about why most people are using pop filters? Simple. The inverse square law also says rushing air dissipates according to the inverse square law. Most people seem to be using their pop filter many inches away from their microphones; that is, the pop filters are too far away to feel the effect of the plosives!
They just take up space, the user believing they send some visual cue that they’re running a professional podcast.
Anyway, pop filters don’t do any harm. So why do I care?
I care because it indicates most people don’t practice what they preach in their respect for science. Supposedly they learned the basics of the inverse square law in science class. Supposedly they understand enough of the scientific method that they’d test the usefulness of the technology they use. That’s what I’ll comment on YouTube. Forget the math or laws. Just take 2 minutes to test it yourself.
Few have 2 minutes to test pop filters or think about how an ignorance of the inverse square law affects human decision making.
But I get it. The wish, the hopefulness, that our creativity will impress everyone, once we get the right microphone and pop filter, is a hard thing to pass up. I too buy equipment that is more, probably, all wish fulfillment.
But at least I know enough to hate myself ;)
I’ve also created a YouTube video on this subject Pop Filters: What They Don’t Tell You.
