What is a Condenser Microphone and Do You Really Need One?

There is a truly dizzying array of microphones available for all kinds of particular purposes. Which one is right for you? Let me begin by making the most basic distinction there is among microphones: Dynamic versus condenser microphones. To understand the difference between the two, I need to give you a very quick crash course on the science behind microphones (don’t worry, there won’t be a test). A microphone is a transducer device, meaning it takes one form of energy and transforms it into another form of energy. All microphones contain a diaphragm, which is a thin material (plastic, paper, aluminum, etc.) that vibrates when sound waves hit it. The other components in the microphone convert those vibrations into electric currents that are called audio signals.

Dynamic vs Condenser

A dynamic microphone uses a wire coil and a magnet to create the audio signal. The wire coil is attached to the diaphragm in order to receive its vibrations.

A condenser microphone uses a capacitor to generate the audio signal. A capacitor is an electronic component that stores energy as an electrostatic field. A condenser microphone requires electric power either from an internal battery or an external phantom power source to send voltage through its plates, one of which is the diaphragm, in order to generate the audio signal.

dynamic vs condenser

Dynamic vs Condenser

Dynamic Microphones

Dynamic microphones tend to be sturdier and less expensive than condenser microphones. They can take more of a beating than condenser microphones, which is why they are often used for stage mics in live performances, especially with very loud instruments and vocals. The disadvantage in a dynamic mic is that it’s not as accurate at reproducing more subtle nuances in sound because they have a more limited frequency response. Rock bands that perform live often use dynamic mics not only because they’re rugged, but because they tone down loud instruments like drums and screaming guitars (and screaming singers, for that matter).

Condenser Microphones

By contrast, a condenser microphone is more sensitive, but this sensitivity comes with increased fragility. That doesn’t mean they can’t be used in the live performance setting. However, they will often be placed well out of reach of any physical contact, such as microphones suspended above a choral performance. Still, if what you’re after is a more accurate reproduction of the richness and nuances of sound over as wide a range of frequencies as possible, the condenser microphone is the obvious choice. Applications where it makes sense to use a condenser mic would include the following: Narrating an audio book or any spoken word vocals in a studio; a capella singing or singing accompanied by acoustic instrumentation in a studio; non-amplified non-electric acoustic instruments in a studio (guitar, cello, upright bass, piano, etc.); and live choral or orchestral performances.

Another primary distinction to keep in mind within the field of condenser microphones is the size of the diaphragm. For the most part, condenser microphones will be come in either large-diaphragm or small-diaphragm versions. The large-diaphragm condenser microphone is an all-around workhorse that is good for recording just about anything, from vocals to percussion to brass to strings. Versatility is the name of the game when it comes to large-diaphragm condenser microphones. Because of this, many people fail to realize that the small-diaphragm condenser microphone has its place as well. Where it really shines is in any situation where your goal is to capture extended overtones and sharp transients – acoustic guitar, harp, the hi-hat on a drum kit – these instruments have a rapid attack to each sound that can get lost with other microphones. The small-diaphragm condenser mic captures these sounds more precisely because their smaller, lighter-weight diaphragms are more sensitive and responsive to the sound waves hitting them.

With those basics in place, I’ll walk you through a number of different types of condenser microphones and tell you what they are best used for. The three I’ll focus on in this article are tube, stereo, and vocal condenser microphones. Here’s what you need to know about each one:

Tube Condenser Microphones

Tube Condenser MicrophoneTube condenser microphones hearken back to the golden age of radio broadcasting. Instead of using a transistor circuit, they contain a vacuum tube (also called a valve circuit) to amplify the current. For many people, the fact that tube condenser microphones were used by such recording icons as The Beatles, The Rolling Stones, and Pink Floyd is more than enough reason to want to buy and use them. But there’s also more to it than that. While other condenser microphones can achieve a more technically accurate reproduction of sound, lots of people have grown to admire the particular way in which tube condenser microphones change the tone of the sound they take in. They tend to impart a slightly warmer quality to sound. Other describe it as a more vintage sound. Still others claim that they have the ability to bring out harmonic overtones lacking in other microphones. This makes them particularly appealing to those involved in recording the spoken word as well as folk-style ballads with softer vocals and acoustic instrumentation.

Stereo Condenser Microphones

Stereo Condenser MicrophonesStereo recording is important for capturing the most realistic sound in those situations where there is significant variation in where different sounds are coming from, whether that be from left-to-right or front-to-back. Someone narrating an audio book would not need to worry about capturing any positional nuance. Stereo recording is unnecessary as it is better in that instance to use a microphone that is more targeted towards catching only the sound directly in front of it since there is little to no positional variation in the sound being produced. But if you want to bring a lifelike realism to a recording, such as an accurate rendering of an ensemble of instruments or singers where there is variation in the sound coming from different positions in the performance space, stereo recording becomes highly desirable. It allows the listener to hear where each instrument or singer is located. There are two ways of achieving the stereo effect. One is to use pairs of microphones, focusing one towards the left and one towards the right (and/or one at the front and one at the back) of the musicians. The other option is to use a single microphone that has two capsules on it that are either preconfigured or can be adjusted for stereo recording. Stereo microphones are crafted to come as close as possible to reproducing human hearing. An ideal setup for recording acoustic piano, for example, would to place a large-diaphragm condenser microphone at end of the piano producing lower notes and a small-diaphragm condenser microphone at the other end producing the higher notes.

Vocal Condenser Microphones

Vocal Condenser MicrophonesThe vocal condenser microphone is one that has been crafted with the intention of capturing vocals. It is far superior to dynamic microphones in its ability pick up the higher frequencies, making it particularly well suited to high-quality renderings of breathier vocals. It is also superior in its capacity to capture the finer details that can occur in a singer’s voice. Again, if what you’re recording is a screaming rock singer, stick with a dynamic mic. But if you want to explore a fuller range of nuance and subtlety in the human voice, a vocal condenser microphone is the one for you. If you’re a singer-songwriter of ballads, you’ll want to try out several different vocal condenser microphones to find the one that’s right for you.

One way of judging among different condenser microphones of the same type is by examining their technical specifications. Be wary of any microphone that does not provide a particular specification – this usually means that aspect of the mic is so poor that the company doesn’t even want to talk about it! Here are the three primary specs you should pay close attention to:

Impedance: The lower the better because that means the mic will pick up less low-level noise. Professional-grade microphones will have impedance levels of 200 Ohms or less. However, anything in the range of 50-1,000 ohms is still considered low impedance.

Sensitivity is a microphone’s ability to pick up lower volume sounds. It is expressed as a decibal value with a plus/minus variance, such as -65dB ± 5dB. You want to go for a higher value with the least amount of variance. Because sensitivity values are expressed as negative numbers, the closer you get to zero the more sensitive the microphone. A mic with -40dB sensitivity is more sensitive than one with a -65dB rating.

Frequency range will indicate how wide a range of sound can be captured. It will be expressed as range such as 40Hz-16kHz. Generally speaking, a bigger frequency range is better.

Final Notice

Whatever type of microphone you’re looking for, there are going to be high-end and low-end versions of it. In general, a higher price typically indicates a higher quality, and a lower price often signals lower quality. The trick for you is figure out what combination of quality and price is going best meet your needs. If you’re ready to begin exploring which condenser microphones are available in affordable price ranges, be forewarned that searching the Internet for this information can easily lead you to a place of frustration and feeling overwhelmed. The sheer volume of data and options is mind-boggling. The good news is that I have done a big chunk of this research for you. I have a great article you should read called Cheap Condenser Microphones for Less than $100. The article presents options for each type of condenser microphone you learned about here, all of which are solid on technical specifications but easy on your budget.