Microphone Types Explained

If you’re looking to buy a mic for your vocals, the first thing you have to understand is what type of mic you’re buying and why.

Nobody abhors technical information more than me–I’m all about the music–but if you’re going to invest in a microphone, then you will save yourself all sorts of time and trouble if you learn the basics. And when I say “basics,” please understand, this information comes from real-world knowledge acquired over a 30 year career of recording everything from major label national acts to smaller regional acts at home with no budget whatsoever. Through those varied experiences, I’ve used nearly every mic you can imagine, and I’d like to break down in the simplest possible terms, the different types of mics and how they shine. This way, you’ll have a far better chance of getting the right mic for the job.

From my latest book, MIXERMAN Musician’s Survival Guide to a Killer Record

Microphones

When it comes to microphones, it’s more important to understand how and where they shine. The brand of mic is of far less consequence than the type. Therefore, you need to understand certain aspects of mic design, because they relate directly to your decision-making process.

The Capsule

Microphones have a capsule, which is simply a membrane suspended in a housing. Basically, that round thing inside the microphone grate reacts to the sound waves, which are then somehow converted into an electrical signal. Don’t ask me how. I still haven’t figured it out. But that’s what it does.

Pick-Up Patterns

Every capsule has a pick-up pattern, which describes the overall manner in which a mic collects and rejects sonic information. What the hell does that mean? Well, sometimes you want a mic to pick up lots of information around it. And sometimes you want a mic to pick up just the sonic information directly in front of it. The pick-up pattern is what determines this. On some mics the pick-up pattern is selectable. On other mics the capsules are modular and can be swapped out by the end user. Most mics have only one available pattern, which is usually all you’ll need. They call it cardioid.

Cardioid

You’ve probably heard people call their mic a cardioid mic. That’s not a brand. It’s a pick-up pattern, and it’s the most common pick-up pattern around. Cardioid really just means heart shaped.

Cardioid patterns are relatively tight in nature, which means they mostly pick up information directly in front of them. They’re also subject to something we call “proximity effect.” When you place a cardioid microphone in close proximity to a source, like a singer, you will get a boost in low-end information. You may also get some measure of distortion, but that’s not always a bad thing. In fact, you can use proximity effect to your advantage. If you want more low end out of your capture, just move the mic closer to it. If you want less, just pull the mic back. Do you see how simple recording is when you don’t clutter your brain with too much useless technical information?

For the most part, the mics that you have will employ a cardioid pick-up pattern. But there are other patterns available. There’s hyper-cardioid and super-cardioid, which are even tighter and, therefore, more directional in nature than cardioid. These aren’t as commonly used in the recording studio. The most prevalent alternative pick-up patterns would be omnidirectional and figure-8.

Omnidirectional

Basically, when a capsule is set to omnidirectional, it picks up sonic information in all directions evenly around the microphone. This is particularly useful for “gang vocals” as your crew can surround the microphone, which will then pick them up evenly around the mic.

It’s important to note, omnidirectional patterns are not subject to proximity effect, but given the 360 degree pickup pattern, you’ll collect considerably more room information than with the more directional cardioid patterns. For most recording applications, omni is not a desirable pattern. But it can be exceptionally useful when you want to surround the mic with performers, or if you seek some level of ambient information in your capture.

Figure-8

A figure-8 pattern picks up information from the front and the rear of the capsule, and rejects the side information. This can be useful for recording two performers facing each other. Keep in mind, both sides of the capsule go to just one preamp, so you need to get the blend between your performers right at the mic.

Nearly all ribbon microphones are figure-8 by design. Some condenser microphones allow you to switch between the cardioid and figure-8 patterns. Some mics even allow you to select varying degrees of those patterns.

Powered Microphones

Some microphones require a power source as part of their design. Most powered mics accept 48 volts of phantom power, which you can typically send to the mic from the preamp. This function is usually labeled on the preamp as “48V” and should include a bright red light to let you know when it’s activated. There are two very good reasons for that red light. You can fry many ribbon microphones with 48 volts of power, and a mic that requires power won’t reproduce sound without it. Really, it’s not advisable to plug any mic into 48 volts hot. It will cause your monitors to pop violently.

The inclusion of a powered transformer in a microphone has to do with design considerations, and should have no bearing on mic selection. If it needs power, send it power. If it doesn’t, don’t.

Tube Microphones

Some condenser microphones incorporate a vacuum tube for purposes of amplification and derive voltage from their own dedicated power supply. The mic won’t sound without it, nor will it operate on phantom power. In general, tubes are warmer in tone than solid state microphones, which can be beneficial on strident instruments.

Plugging a tube mic into a live power supply is a great way to give yourself a nasty shock. Do yourself a favor and make sure the power supply is off for at least 30 seconds before connecting or disconnecting your mic to it. You’ve been warned.

Microphone Types

Now that we understand the pick-up patterns, let’s talk about the types of microphones. For the purposes of this Survival Guide. there are five types of mics that you will come across: small diaphragm condensers (SDC), large diaphragm condensers (LDC), ribbons, dynamics, and speaker mics.

Condenser Microphones

Condensers have a fast transient response, full frequency range, and robust gain, all of which is just a fancy way to say they’re sensitive to sound. That means condensers don’t require an especially loud source to excite the capsule. There are two basic kinds of studio condenser mics—small diaphragm and large.

Small Diaphragm Condenser (SDC)

Small diaphragm condensers tend to have a wide cardioid pickup pattern, which means they excel at capturing off-axis information, and can offer a detailed sonic image when used in pairs for stereo miking. If you want to get a nice aggregate stereo image of a drum kit, a pair of SDCs overhead can be an excellent choice.

Large Diaphragm Condenser (LDC)

The large diaphragm condenser is probably the most widely used studio mic there is. The LDC capsule is larger than that of the small condenser, which seems to make a whole lot of sense given the definitions of large and small.

LDCs, like SDCs, are sensitive microphones, but aren’t as good at picking up off-axis information as their smaller counterparts. The size of the capsule leads many to believe that LDCs have a more extended low end, which is a myth. Generally speaking, you will get a full frequency response from any studio condenser.

LDCs are often the first choice for vocals, drum overheads, room mics, stringed instruments, etc. Seriously, these bad boys are a good choice on just about any source, so long as there’s space to fit the mic.

Dynamic Microphones

A dynamic microphone diaphragm operates similarly to the woofer in your monitors in that the diaphragm is connected to an induction coil and magnets. That’s about as technical as we need to get.

These are workhorse microphones that are less susceptible to damage from abuse and moisture, which is why they are so commonly used for live reinforcement. Make no mistake, dynamics are a staple in the studio, as well, and they can take downright oppressive sound pressure levels without ill effects.

Dynamics also exhibit excellent rejection properties, which means they don’t pick up information on the sides all that well. This can be an important consideration when choosing a mic. Like those times when you’ve got a microphone pointing at a snare drum in close proximity to a hi hat and cymbals. In most cases, you’ll want lots of snare drum and not a lot of that brass on the mic. As you can imagine, good rejection properties would be a useful feature for a mic placed in such a precarious position.

Dynamic mics don’t have the full transient response of condensers and, therefore, aren’t used for purposes of fidelity to the source. If you want to capture a tom drum tone accurately, you would be better off with a condenser placed a foot or two off the head. Unfortunately, this kind of placement would pretty much make it an overhead on a full drum kit. Even if you place condensers in close proximity to the toms, you’ll still pick up a ton of cymbal information. Dynamics in close proximity will pick up more low-end information from the tom than top-end information from the cymbals, often making them the best choice.

In general, we use the close mics on a drum kit to fill in missing information. For instance, if you place a pair of SDCs in a stereo configuration (which we’ll discuss shortly) over the drums, they will pick up a rather accurate image of the drums in that space. But because the SDCs are several feet from the toms, you won’t benefit from proximity effect. As a result, there can be a definitive lack of low end. We can fill in that low-end information by placing dynamic mics in close proximity to the toms and snare, and then blending them in with the overhead image.

Here’s the thing though. While it’s true that dynamic mics aren’t as sensitive to sound pressure levels as condensers, they are way more sensitive to placement. The dynamic mics’ general lack of sensitivity and capsule speed virtually requires proximity to the source. Therefore, the tiniest movement in any direction of a dynamic mic can, and will, result in a notable differential in tone. This is important to understand, because in certain situations, a dynamic mic can make you work harder than you should. There are many engineers who enjoy dicking around with dynamic mics in front of a guitar cabinet. Personally, I prefer the far more forgiving ribbon or condenser for that application.

Since dynamic mics lack sensitivity, they aren’t the greatest choice for miking from distance. A dynamic over the drums is going to sound quite trashy, which is great if you’re making a punk record, or if you want lo-fi drums. But in general, your dynamic mics work better close to the source.

For whatever reason, there are times that a dynamic is the optimal vocal mic. That said, they can be a major pain in the ass for this application because of their sensitivity to position and the general mobility of singers. Given this, dynamic mics are often preferable on stationary sound sources, but this is by no means any kind of rule.

Singers use dynamic mics almost exclusively for live performance, but it’s generally better if you don’t hold the mic while performing the record. Hey, if it makes for a better performance, go for it. But you very well could get a ton of noise from the handling of the mic.

Dynamics are exceptional at rejecting ambient room information, particularly when placed in close proximity to robust sound pressure levels. Lastly, dynamic mics do not generally require a power source. Nice.

Ribbons

The capsule from a ribbon mic is made from an extremely thin strip of corrugated aluminum suspended in a strong magnetic field. Ribbon mics are technically dynamics because they employ an induction coil, but we don’t ever refer to them that way because they have such unique capture properties. As such, ribbon mics get their own classification–quite simply, ribbons.

Due to a generally steep rolloff above 16 kHz, ribbons have a rather smooth top end, and can often be perceived as dark in nature. They also have a rather slow response to transients, which can have the effect of rounding off those transients. Given this, ribbon mics are used to great effect to capture drum overheads, guitars, and even vocals. And there is nothing quite like a good ribbon for capturing your more strident brass instruments.

Many ribbons can’t take an excessively loud source. An aggressively played kik drum can disintegrate a ribbon membrane in an instant, so be mindful of where you place them. That said, some of the relatively newer lines of ribbon microphones can handle just about any source at any level, including a blaring guitar amp. In other words, if you have a ribbon mic, make sure you understand its design tolerances.

As I pointed out earlier, the large preponderance of ribbon mics are bi-directional, which means they have a figure-8 pattern—the rear pattern often brighter than the front. And although a surge of 48 volts can disintegrate the ribbon membrane under the right circumstances, there are some ribbons that require phantom power.

The longer I produce, the more ribbons I employ in my recordings. Ribbons may have a steep roll-off on the top end, but that just means you can brighten the shit out of them without bringing up annoying sizzle distortion that some cheap condensers introduce. As much as I’m a proponent of distortion, top-end sizzle is particularly exhausting, and should be avoided when possible.

If you’re a musician recording at home, in all likelihood you don’t have a ribbon mic available to you. I’ve recorded all sorts of records without a single ribbon, so they are by no means a requirement. They are, however, a great addition to your arsenal over time.

Enjoy, #mixerman

P.S. There are a few more mic designs that I discuss in the book, including speaker mics, USB mics, and stereo mics, now of which I would use on a vocal beyond some extreme creative circumstance.

P.P.S. Now that you’ve read all of that, there are a ton of great mics out there, but for me, I love the entire LEWITT line. Even their lower priced large diaphragm condensers blow away far more expensive options. I really don’t know how they do it. Anyway, that’s my recommendation if you want it.

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People love this book! There are tons of five star reviews on Amazon. Larry Crane of TapeOp raved about it: “I think I’ll be buying cases of this book and handing it out as people enter my studio.” Why would a studio owner/ recording engineer (and publisher) give a book on recording to his clients? Because the more his clients understand about recording, the easier his life becomes. That’s why.

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