Microphones: What you need to know before you buy

Thanks to advances in digital recording technology, putting music to proverbial tape at home is as easy as picking up a microphone, plugging into an audio interface, and running some audio production software on your computer. If you're just getting started, the first thing you need to consider is the microphone—the hardware with the most impact on sound quality.

Choosing between mic types

It's an understatement to say all microphones are created differently. Unique technology in different types of mics can lead to vastly different audio recording qualities, so knowing what each type of microphone offers is critical to deciding on the right one.

Dynamic Microphones:  Known for their versatility and simple, sturdy design, dynamic microphones are available in a wide range of prices and levels of quality. You'll find models such as the Nady SP-4C for $20 on the one hand, and high-end mics such as the Electro-Voice RE20 that push the $500 mark on the other. While the difference in audio quality between less expensive models and their more expensive cousins can be huge, the technology is more or less the same.

Shure SM57 dynamic microphone

Dynamic microphones are essentially mini loudspeakers that work in reverse: Where speakers convert electrical signals into sound, dynamic microphones work in the other direction, converting sound waves to electricity. Inside every dynamic mic, you'll find a wire coil next to a magnet. When sound waves hit the coil, it vibrates in relation to the magnet. This creates an electrical current that is fed through a wire out of the mic and into your computer or recording device.

This simple design means that dynamic mics can take a lot more abuse than other types of microphones, making them the recording tool of choice for musicians looking for longevity and durability. Dynamic mics can also respond to the loudest sound sources (think cranked-up electric guitar amps and bass drums) so you'll often see dynamic mics such as the popular Shure SM57 at live shows. Another benefit of the SM57 is its price: It generally retails for around $100—considerably less than other microphones of similar audio quality.

Condenser Microphones: Look inside a condenser microphone, and you'll see a setup that's considerably more complex than that of a dynamic mic. This microphone can produce a stronger audio signal, making it more sensitive and responsive than its dynamic cousin. For that reason, condenser mics are often used for recording the subtle sounds of acoustic instruments.

Rode NT1-A condenser microphone

All that extra sensitivity comes with some conditions, however. Instead of a wire coil, all condenser microphones have two capacitor plates that require power from an external source. That means you'll need to supply what's called "phantom power" by connecting the microphone to a mixer or other powered device via an XLR cable. So if you want to use a condenser microphone in your home studio, be aware it's going to require some extra hardware to work.

Another thing to keep in mind before buying a condenser mic is durability. Because of their relatively complex technology, a bad drop or shock can spell the end of this type of microphone. The internal design also means condenser mics are generally more expensive than dynamic mics, making it hurt all the more if you lose one to an accident. So if  you need something heavy-duty, it may be smart to invest in a dynamic mic instead. However, if enhanced recording sensitivity is still calling your name, the Rode NT1-Aa popular go-to condenser mic for many musicians, generally sells for around $230.

Blue Microphones Woodpecker ribbon microphone

Ribbon Microphones: Ribbon mics are technically dynamic microphones—their internal mechanisms are essentially the same— except instead of a wire coil, there's a single, thin metal conductor or ribbon that vibrates from direct contact with sound waves. These mics are a bit harder to find than dynamics and condensers, and are very fragile. Thanks to the thin metal conductor, a strong blast of air from a bass drum or accidentally exposing one to a phantom power source could ruin this sensitive piece of equipment. These microphones are also expensive, with some like the Blue Microphones Woodpecker pushing $1,000 and beyond.

Despite their fragility and price, ribbon mics are favored by some musicians for their warm, detailed sound.

Getting the verbiage straight

While the differences between dynamic and condenser mics can be heard directly in a recording, you should also be familiar with terms like directionality, impedance, and frequency response before you make your final selection.

A microphone's directionality describes how it picks up sound from various directions. While some microphones simply pick up sound from every direction simultaneously, most microphones are limited to a specific direction, which you can use to your advantage when recording.

Omnidirectional:  These microphones pick up sound from every direction. Because of their tendency to pick up unwanted background noise, they're generally used for broadcasting or reporting instead of music. For example, check out the Sennheiser MD42 ($200).

Cardioid:  The word cardioid literally means "heart-shaped," and it's an accurate description of these mics' directionality. Cardioid mics pick up sound primarily from the front where the microphone is pointing, as well as a little from the sides, and are the most common mics used for recording music. The Apogee MiC USB condenser microphone ($200) is a good example of a mic with cardioid directionality.

An example of a cardioid polar pattern.

Bidirectional:  Also referred to as figure-eight directionality, this pattern picks up sound from two opposite sides of the microphone. There aren't too many uses for this when recording music in an amateur setting, but these mics are popular for podcasting. Look at the Shure Beta 181/BI ($500) for an example of this kind of microphone.

Variable directionality:  Some mics can switch between different directionalities. This provides more versatility than with standard mics. The Blue Yeti ($150) is a great example, and a popular choice with home users because of its USB connection.

Impedance: This term refers to a microphone's receptiveness to AC current or audio signal. Measured in ohms, low impedance mics (600 ohms or lower) are better at retaining audio quality when using cables longer than about 16 feet (approximately 5 meters). While those issues shouldn't affect most home setups, a high impedance can often be a sign that the microphone's other components are of lower quality.

Frequency Response: Microphone manufacturers love to boast about their products' frequency response, which is essentially the range of frequencies a microphone is capable of detecting. However, just knowing the range won't help you much—what you really need to know is how responsive the mic is to specific frequencies. Think about what you will be recording before you pick a microphone: A mic that is good at picking up mid-range and high frequencies is a good choice for vocals and guitar, while you'll want a mic that excels at low frequencies for recording bass.

What should you buy?

Determining what microphone to buy is all about considering what style of broadcast or music you want to create and choosing the equipment that gives you the best chance of producing your desired sound. A dynamic microphone such as the Electro-Voice RE20, while a bit spendy, is made for recording deep vocals and percussion instruments. If you're looking for rich-sounding acoustic recording, a condenser mic such as the Rode NT-1A could fit the bill. Recording loud electric guitar requires a microphone that can take a sonic punch, such as the Shure SM57, which retains sensitivity at high sound levels.

If you don't have a lot of money to spend, picking a microphone that excels at recording in a number of different environments will let you record entire compositions with a single mic. A number of versatile dynamic and condenser microphones are up to the task. Just be aware that you'll sacrifice some sound accuracy at certain frequency levels.

This is the first of a three-part series on how to set up a home-based music-recording studio. Part two, which runs tomorrow, talks about mixers and audio interfaces.

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