Kpopalypse’s music theory class for dumbass k-pop fans: part 19 – recording vocals with microphones
It’s time for the return of the Kpopalypse music theory series! This episode is all about using microphones to record vocals!
Since k-pop fans are creepily obsessed with vocals, it’s time to cater to their weird obsessions. Some of the more observant fans have noticed that k-pop singers tend to sing with their mouth up against strange objects, and wonder a little about these objects, how they work and what they do. This post will attempt to demystify these objects known as microphones, how and where they are used, as well as teach you how to actually get a decent quality sound vocal recording with one should you choose to do so. (I’ll cover instrumental recording in another episode of this series.)
HOW A MICROPHONE WORKS (BASICALLY)
In principle, a microphone is a very simple device. What it does it captures vibrations in the air using a thin film called a diaphragm which vibrates in sympathy with the air around it, and then uses electromagnets to convert these vibrations into electrical current. This signal is then transferred out of the microphone to whatever you plug the microphone into. Note that a microphone is essentially the opposite of a speaker, which does exactly the same equation in reverse – a speaker converts electrical current into physical wave motion by using the current to move the air using a speaker cone. This means that all speakers are potentially microphones, and vice versa.
This is the most simple example of how microphones work, but there are more complex examples. For instance, in the case of digital USB microphones, there’s an extra step: the electrical current is then converted again into digital data by chips onboard the microphone before then being output through the USB cable as a digital data stream. Wireless microphones also have an extra step, where a radio transmitter converts the electrical current to a radio signal, and a receiver converts it back to electrical current at the other end, saving the need for a cable. However most microphones in the professional audio space are pure analog, and output electrical current through a 3-pin XLR connection, without any extra signal conversion. The main reason for the continued dominance of analog microphones is durability – while USB is fine for a home recording set up, and wireless microphones are fine if they belong to one very diligent user who treats them carefully, microphones “in the field” (either a pro recording studio or a live stage environment) tend to receive lots of punishment. Sensitive electronic transmitters and USB connections are delicate and almost always the first thing to break on a microphone that is subjected to the rigours of constant use.
There are also microphones that use a standard jack connection (either the large 6.35mm guitar size or one the smaller mobile phone sizes) but these are only seen on cheap microphones that are found in supermarkets/electronic hobby stores or bundled with stereo systems, and it’s a telltale sign that your microphone sucks if it only uses this type of connection. Some ultra cheap-ass microphones even have a jack lead hard-molded into them which can’t be removed. Definitely avoid these types of microphones for any professional quality recording, the results won’t be good (unless you’re making music in a niche style where nobody really cares about recording quality, like black metal, or crust punk, or an Iz*one song).
TYPES OF MICROPHONES
Microphones come in various different classifications but there’s only two types that are relevant for singing vocals in the modern age:
Dynamic microphones are low range and have a low output signal. These are most commonly used for live stage performance, where high range is often a drawback rather than a benefit, because in this scenario you want the microphone to pick up only what is right in front of it, and as few other sounds as possible.
Condensor microphones have a higher range as they are more sensitive. These are preferred for studio recordings in situations where capturing the most detailed sound is a priority, and also for situations where you may need to record everything in an entire room or area with just one or two microphones. Vocals in the studio are almost always recorded with condensor microphones, and the headset microphones that Korean pop performers wear onstage are most commonly (but not always) condensors as well. Condensor microphones often require “phantom power”, which is a separate power signal that can be sent from a mixing desk into a microphone, through the XLR cable (in a wireless headset condensor microphone, this power comes from the batteries in the radio pack).
Here’s a comparison of frequency response between a condensor microphone (red) and a dynamic microphone (blue), so you can get an idea of the difference in audio quality.
In the graphs, from left to right is from bass to treble, and the vertical axis is volume. Note that the dynamic microphone doesn’t perform at all well in the bass register (below 150Hz) and also has a lump of around +8dB at 5KHz. The condensor microphone while also not perfect has a much “flatter” response curve overall which means that it would give a truer reflection of the original sound with less ‘coloration’. Note that there’s no reliable way to tell just from appearance whether a microphone is dynamic or condensor, it requires familiarity with the microphone model, so just check the tech specs online if unsure.
To give you an idea of the sensitivity of condensor vs dynamic microphones:
Lil Cherry is rapping into a condensor microphone on this video. Her distance from the microphone might seem excessive, and therefore give rise to suspicions of miming etc, but in fact it’s accurate and the performance is real. She’s standing at about the correct distance away (25-50 cm) to get the best sound out of this type of microphone.
Eric Reprid is standing a similar distance away from this microphone (and amazingly, he’s singing/rapping into the correct part of it) but he’s got one thing wrong – the Shure Super 55 is a dynamic microphone, not a condensor, so he’s actually too far away from it to be getting such a consistent sound, even with compression and Autotune. That’s our main giveaway here that this performance is mimed.
He should have taken a leaf out of LL Cool J’s book, who gets the microphone distance right for a dynamic microphone like the Super 55 in this video. Of course it’s still mimed but nobody’s pretending that this is real, or that rappers can actually win a boxing match.
There are other types of microphones as well, which I won’t go into much detail about but it’s worth knowing that they exist.
Ribbon microphones are uncommonly found, but they give results similar to condensor microphones and are used for similar applications. Initially these microphones found use in radio stations and recording studios pre-WWII, but their use faded thanks to improvements in condensor microphone technology after the war. More recently, ribbon microphones have been coming back into fashion thanks to improvements in nanotechnology making them more durable and reliable, but you’re still very unlikely to find them on a live stage, or anywhere else for that matter, unless you’re dealing with people who are super rich, because ribbon microphones of any decent quality are still quite expensive and out of reach of most buyers.
Piezo/capsule/boundary microphones are designed to be placed on a surface, and when done so they acoustically couple with the surface they are mounted on, meaning that the entire surface then boosts the fidelity of the microphone input. Piezo microphones are most commonly used for recording interviews and conferences, where they are placed on a desk between people who are talking. Piezo microphones are also the most common type of microphone found inside any acoustic guitar that has built-in amplification, with the microphone usually mounted on the underside of the guitar’s soundboard.
Lavalier microphones are the type of microphones that are attached to the tie clips and front pockets of TV presenters and newscasters, they’re useful in situations where having a completely unobstructed face plus completely free hands is a requirement. These microphones compromise fidelity somewhat due to their location and design, so you don’t tend to see these outside of the TV broadcast environment and occasional theater stage performance use.
Shotgun microphones are the big microphones that are often suspended above people’s heads when filming outdoors. These microphones are designed to only pick up sound in exactly the direction they are pointed at and nowhere else, and are more designed for practicality than pristine audio quality. Film studios will usually overdub anything recorded with a shotgun microphone later in the recording studio using a higher quality condensor microphone. Due to their design, shotgun microphones have limited applications outside of film and TV interviews.
So that’s a basic overview of the microphone types that are typically used for voice. Now let’s talk about recording vocals, in three specific environments – on a live stage, for a basic home studio setup, and in a professional studio, plus any considerations that go along with this.
VOCALS – GAIN RIDING
For live vocals there’s really just three options:
- Headset vocal microphone
- Wireless handheld vocal microphone
- Dynamic vocal microphone with a cord (SM58 or similar)
Which one you pick will depend on certain factors. Do the performers need maximum mobility? If so, the headset microphone is the obvious choice, but headset microphones have one huge disadvantage, which is that they prevent “gain riding”. A shit vocalist doesn’t know how to gain-ride a microphone, but a good vocalist will be trained in it and the best ones will do it instinctively.
Lily from NMIXX is an extreme rarity in the commercial end of k-pop because she can actually sing really well and is obviously a trained vocalist. In the above video watch the distance between Lily’s lips and the microphone change from 0:57 to 1:01. As Lily increases the volume of her voice, she moves the microphone away from her lips just slightly, so the volume of her voice on the high notes going into the desk doesn’t experience a huge change, but a more gradual shift. This is basically a manual way to apply some vocal compression and it results in a much smoother listening experience, as well as a better experience for the audio engineer – because Lily is doing her own gain-adjusting at the source, the audio engineer doesn’t have to adjust anything.
Another outstanding vocalist who you won’t hear much about because it’s not all that trendy to talk about her because she’s in a proper rock group and not some shit idol pop group, is Jayoung from Rolling Quartz. Note how at 1:41 she has her mouth pretty far away from the microphone for the long, sustained powerful notes, but from 1:54 when she goes into singing a verse at a much lower vocal power level, her microphone is right up close to her face.
Of course, if you’re wearing a headset, you can’t do any of this, which means that you’ll be relying on electronic compression to adjust the levels of your vocals on the fly. Electronic compression is good, but it’s rarely perfect, especially in a live environment where depending on logistical requirements there may be limited time to even set the damn compressor up and check it. This means that even the best headset microphones always have a level of compromise built into them compared to something that is hand-held or free-standing. If you’ve ever seen a k-pop performance where some people got headset microphones and others didn’t, the better singers are almost the ones with the hand-held microphones, and this is why.
As far as the choice of wireless versus wired microphones, all wireless systems have a tiny bit of latency built into the system, plus you can sometimes lose a bit of fidelity in the radio transmission, so it’s generally better to go with wired. However, once again in an image-centric world like k-pop mobility is important, and the very best wireless microphones don’t have a noticeable performance drop compared to wired microphones anyway. Note there’s a difference between a ‘measurable’ drop vs an ‘audible’ drop. You’re not going to notice a few microseconds of delay, it’s only once you start getting in the 10+ milisecond range that delay becomes noticeable. For this reason, wireless microphones that work on radio transmission are far superior to anything with a USB interface in the chain, one reason why USB as a standard hasn’t really taken off for pro audio.
In a studio environment where you’re looking at a condensor microphone that’s on a stand, you’ll also want to gain-ride by moving away from the microphone during the big notes, and closer to it for the subtle stuff. Rather than stepping away and toward, which can be awkward, you can also tilt your head so you’re singing a little bit ‘past’ the microphone for very strong notes, to bring down the volume a bit. You can see Chanhyuk from AKMU do this here:
Watch him at 1:04, tilting his head slightly to the side, this works just as well as stepping backward, although you may need to experiment with angles a little if it’s a movement you’re not used to.
VOCALS – POP SHIELDING
I have to cover this off or I’ll get asked about it a lot, because this question comes up every couple of months for me even though I’ve talked about it multiple times in a few different places on this site. Take a look at this picture of (G)I-dle’s Soyeon hard at work in the studio.
Notice the black disc that’s between her face and the microphone. That’s a pop shield or pop filter, and its function is to take the wind noise out of her vocals. Right now, put your hand right in front of your face, only a few centimeters away, with your palm facing your mouth, and say the letter “p”. You’ll notice a burst of air hit the palm of your hand. That burst of air will make an ugly bass-heavy noise that will pop your microphone’s diaphragm like a cheese, so using a pop filter is a way to stop that ugly burst of low bass from happening.
If you don’t have a pop shield, here’s a cheap-ass hack if you’re broke – a wire coat hangar bent into a circle with a thin stocking stretched over it will perform the same function. Insert the hook of the coat hangar into a mic stand with the top taken off for stability. Another option is just to make sure the microphone is off-centre slightly to your face, but still pointing at your mouth, this will make sure the air doesn’t blast the diaphragm out. However note that many vocalists have trouble getting into it if the microphone is off-axis.
Of course if it’s a live environment the disc kind of gets in the way and can look stupid, and that’s why headset microphones will have a discreet fuzzy tip to perform the same function.
Hand-held microphones also have fuzzy “socks” that can go over them. You don’t see this often on live stages because these socks are fairly thick and can make the microphone sound dull, you’re more likely to see these being used for outdoor interviews to counteract wind noise. However here’s a rare example of a k-pop singer being given the fuzzy sock treatment, and it’s probably because Ailee is another one of those very rare k-pop singers who can actually sing and thus has enough power to be heard with complete clarity through that thing.
Generally speaking it’s always better to have the microphone on a stand, rather than being held by the performer. This is because movement of the hands can sometimes be picked up by the microphone. The weird ‘cage’ type systems on the big condensor microphones (such as the Neumann above, or the microphones in the Lil Cherry video and the Soyeon picture) are there precisely to send a message to keep your goddamn mitts off the fucking thing so you don’t ruin the sound or break anything, because these microphones are very sensitive and can pick up even the slightest movement. However for live microphones, holding onto the handle is fine, if you do it right. Which brings us to…
FUCKING RAPPERS (OH DEAR)
It’s funny how rap music in general has such an emphasis on “getting on the mic” yet almost nobody in rap even knows how to use a microphone correctly.
Here’s a great example of how to fail as a rapper. Younha here performs fine but the token idol rap guy from CIX who appears to do RM’s part of the song at 1:21, not so much. Rappers (and k-pop idols who think they’re rappers) often think they need to:
- Hold a finger out to their upper lip in order to keep the microphone at a consistent distance from their mouth (do their arm muscles not work for that?)
- Cup the base of the microphone’s capsule and put their fingers all over it in order to make the rapping sound more bass-heavy and badass (it achieves neither of those things, in reality all it will do is create extra feedback and unwanted background noise, assuming you’re not miming anyway of course.)
In truth, he should have just copied Younha’s style of holding the microphone, which was fine. But rappers could never bring themselves to do that because it wouldn’t look cool and gangster, or something. But why is holding the base of the microphone capsule wrong? To explain why, we need to talk about:
MICROPHONE POLAR PATTERNS
Every microphone has a polar pattern, which shows how sensitive the microphone is in certain directions. Hand-held microphones for vocals are always cardioid, supercardioid or hyper-cardioid, and it’s the same with headset microphones. High-end condensor microphones usually have the ability to manually switch between cardioid, figure-8 and omnidirectional.
In the diagram above, the top of each circle represents the front of the microphone, and the bottom represents the back. Omnidirectional microphones pick up sound equally in all directions. Bi-directional microphones pick up equally from the front and the rear. Cardioid picks up mainly from the front, and a little at the sides, but none from the back. Supercardioid and hypercardioid tighten the response at the front of the microphone so there’s less bleed from the sides, but you get a bit more bleed from the back instead (polar patterns are always a compromise in this way). Shotgun can basically be ignored as you won’t be dealing with those for sung vocals.
So what makes a microphone directional? Well, it’s all in when the air from your voice hits different parts of the microphone. Cardioid microphones, which are the most common for live vocals, derive their directional properties from the fact that air hits the front of the microphone’s diaphragm and the rear of the microphone’s diaphragm at different times, via ports in the front and rear of the capsule.
The time difference between these two collisions creates a phenomenon known as “phase cancellation”, meaning that if sound hits the front of the microphone first it passes through with no issue, but if sound hits the rear of the microphone at the same time that it hits the front, that sound gets cancelled out, because you can’t vibrate a diaphragm in two opposite directions at the same time – it has to go one way or the other. The two forces cancel each other out.
This is why a cardioid microphone has directional properties and can cancel out sounds partially from the side and completely from the rear, it’s these vents that allow the vibration to pass into the microphone to generate the cancellation (hypercardoid, supercardioid etc, just have differently designed vents that change the timing of the air flow).
By blocking the air vents at the rear of the capsule with your hand like a hip-hop knucklehead because you think holding it that way looks ‘gangster’ or something, now the diaphragm can no longer receive air vibration from both the front and the rear vents – only the front. No matter what angle the signal approaches the microphone from, there will be no cancellation, because the air can only get in one way. This means that every sound the microphone picks up is now equal, and the microphone is now equally sensitive in all directions, or omnidirectional.
Now on a live stage, an omnidirectional vocal microphone is something that you DO NOT WANT, because it will not just pick up you, it will also pick up all the sounds around you, like your own monitoring system, other people around you, their instruments, any nearby fans doing pterodactyl screams, and so on. It instantly creates a disaster that the audio engineer has to then manually compensate for. (There’s nobody more stressed in the music industry than an audio engineer at a rap concert.) If you’ve ever seen someone touch a microphone with their hands and suddenly that microphone squeals and produces ugly horrible feedback, now you know why that suddenly happened. Anyway, now you know more than your favourite rapper about microphones, probably. If you find rappers that consistently use microphones well and never fuck this up please put them in the comments below.
RECORDING VOCALS AT HOME IN A FIXED LOCATION
Good news for people who only record vocals at home in front of their computer desk, there’s several options these days for kick-ass USB microphones that plug straight into your computer. You don’t even need an audio interface for most of them, and the sound quality is comparable to a (much more expensive) studio quality condensor microphone. I personally have been using the Audio Technica AT2020+ USB microphone and I’ve never had a problem with it, every time it’s fucked up it’s been human error i.e my fault. However you’ll find other USB microphones of similar quality. Just be aware of the one huge downside that all USB microphones have, which is the durability of the USB port in the microphone itself. These always wear out ultra quick with enough plugging in and out (if you’ve ever had your favourite USB port on your laptop die, it’s the same shit) so if you’re constantly moving your microphone around and plugging it in and out each day, I would not recommend USB, as the ports often aren’t replaceable and you have to just replace the whole damn mic. Whereas a pro quality microphone with an XLR output will last a lifetime if it’s looked after, even if it’s used very often. On the other hand if your microphone permanently lives by your computer and never, ever is moved or unplugged, USB is a great option that will save you a lot of money on home studio setup costs.
The other thing you’ll need to consider is the room you’re in. Vocal rooms are usually ‘dead’ (no sound reflections) so if you have a lot of echoes in your room you’ll want to put stuff on the walls and maybe ceiling too to deaden the sound. This is a big area and not strictly related to microphones, fortunately I’ve already done a post on it in this series, so you can check that out if you want to know what to consider when deadening your home environment. If you don’t have money for acoustic treatments (which can get expensive), filling your room with tons of shit actually works better than you might think, as long as you can cover the walls with that shit rather than the floor. Bookcases filled with books, CDs vinyls, etc are a great dual-purpose sound absorber.
OH AND JUST SO A KPOPALYPSE ARTICLE ISN’T WRITTEN ABOUT ME IN THE FUTURE THAT HOLDS ME UP TO CONTEMPTUOUS RIDICULE, HOW DO I KNOW WHICH PART OF THE MICROPHONE TO SING INTO, IF IT’S A MICROPHONE I’VE NEVER SEEN BEFORE?
With hand-held microphones it’s generally pretty obvious what to do (point it directly at your mouth like you’re about to deepthroat it), but with condensor and vintage style microphones, maybe less so. Remember these general rules.
- If the microphone is long and thin like a cylinder, you’re usually going to be singing into the top part. Not ‘across’ the top, point the microphone at the roof of your mouth.
- If the microphone is chunky and boxy, you’re usually going to be singing into one side of the box.
- Microphones rely on air being able to get through the capsule into the diaphragm. So if you’re singing into a part of the microphone that doesn’t have any kind of grille to let air through, that’s probably the wrong bit.
- If there’s more than one grille, look for any changes in the colour of the grille on the different sides, usually the correct side will be indicated by something, like a light, or a different colour, etc.
- If all else fails, try actually fucking turning the damn thing on and listening to the result. I know that actually using microphones instead of pretending to use them isn’t normally done in k-pop but you would be amazed at the results you can achieve when you actually record stuff for real instead of mime it.
That’s all for this post! The music theory series will return!
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