Dynamic vs Condenser Microphones: How Each Hears Sound

A microphone turns sound waves into an electrical signal, and the two most common designs do it in different ways. A dynamic microphone uses a coil moving in a magnetic field and needs no power, while a condenser microphone senses the changing gap to a charged plate and does need power. This article explains both, with material from Shure, a microphone maker, and the Historical Voices oral history guide.

What every microphone has to do

Sound is moving air. Every microphone has a thin, light surface called a diaphragm that is pushed back and forth by the changing air pressure. The difference between designs lies in how that tiny movement is turned into electricity.

How a dynamic microphone works

Shure describes the dynamic element as a diaphragm with a voice coil attached, sitting in the field of a magnet. When sound moves the diaphragm, the coil moves within the magnetic field, and this generates the signal. Historical Voices adds that the diaphragm is a Mylar film and that the coil is suspended in the magnetic field. The idea is much like a loudspeaker working in reverse.

Because the diaphragm and coil together have some weight, the Historical Voices guide says dynamic microphones may not respond well to sharp transient sounds, meaning very sudden sounds. In exchange, it calls them rugged, low in cost and in no need of external power.

How a condenser microphone works

Shure says a condenser has a thinner diaphragm placed close to an electrically charged back plate. Vibration changes the spacing between them, which changes the signal. Historical Voices explains it more fully: a light plastic diaphragm, coated with gold or nickel, sits near a fixed backplate, and a 48 volt phantom power supply charges the plates, so that the capacitance, the ability to store charge, changes as the diaphragm moves.

The light diaphragm is the reason condensers respond so closely to subtle detail. Shure says their low mass lets them pick up quiet sounds and high frequencies, and the Historical Voices guide says it gives very accurate response, often with a rich frequency and dynamic range.

What phantom power is

Shure says condenser microphones need a power source, either a battery inside the microphone or phantom power sent down the cable from a mixer or recorder. Most accept roughly 12 to 48 volts, and some studio models need the highest voltage. Shure advises checking that your mixer or recorder supplies phantom power before using a condenser microphone.

Strengths and trade-offs

• Dynamic: handles very loud sounds. Shure says a typical SM58 would need more than 150 decibels of sound pressure level to distort. It also tolerates rough handling, temperature and moisture.
• Condenser: more sensitive and better at high-frequency detail and percussive sounds, but it needs power and, according to Historical Voices, is more fragile and less convenient in the field.

Where each is typically used

Shure suggests condensers for acoustic guitar, stringed instruments, cymbals, nature recordings and sound effects. It adds that condensers can be made very small, which is why lavalier clip-on, headworn and thin gooseneck microphones are usually condensers. The rugged, power-free character of dynamics makes them a natural fit where handling is rough or no power is available, such as the field recorders mentioned by Historical Voices.

Choosing between them

The choice comes down to the sound and the setting. A sturdy dynamic microphone suits loud or rough conditions and needs only a cable. A condenser suits quiet, detailed sources and needs a power supply and gentler care. Many recording setups use both, picking one per source. Product recommendations are beyond what these sources set out, so this is a general explanation of the designs rather than a buying guide.

Sources

• Mic Basics: Transducers, Shure
• Microphone introduction, Historical Voices