The debate between condenser mics and dynamic mics will always be a relevant debate. Anyone who owns a handful of microphones probably has at least one condenser microphone and one dynamic microphone. In my experience with both live and studio sound, I have seen countless applications of condenser mics and dynamic mics, sometimes even for the same instrument. Each time I ask the engineer why they chose that microphone for that application, the answer is almost always some manifesto about how that is the only way to do it. In this post, I’ll be explaining the differences between these two types of microphones and you can make your own decision as to how you’ll use these two common types of microphones.
Dynamic vs. Condenser Microphones
All types of microphones do the same thing: capture sound so that it can be amplified or recorded. There are several different ways to capture sound. The first sound capture device was a gramophone. Many of us have seen these devices in movies and television. A gramophone was like a record player with a giant horn, but this type of record player worked in reverse. A blank record was placed on the table and as you made sound into the horn, a needle etched those sound vibrations into the record so that you could play it back on a standard record player.
Now, obviously, microphones are a bit different. Microphones convert sound into an analog signal. The two types of signal are analog and digital. Analog sound is sound waves traveling through some sort of transducer whereas digital sound is analog sound converted into numbers. Think about a picture you have viewed on a computer. At first glance it might look real depending on the quality of your monitor. As you zoom in on the picture, you start to notice edges becoming a little ugly and eventually you can see individual pictures. This happens when you convert analog sound to digital sound. If you look very closely at an analog signal that has been converted into digital signal, you notice “aliasing.” Aliasing is the inevitable error that occurs when each fraction signal is rounded to one number or the next to accommodate a digital format. Nowadays, this is not a huge issue as the depth of digital signal has grown so great that the aliasing is almost completely indistinguishable.
In all microphones, there must be some type of membrane that converts sound waves into sound signal. In other words, microphones take one form of energy and convert it to another. The technology in this membrane is what separates one type of microphone from the next. Dynamic and condenser microphones are named for their unique technologies.
Dynamic microphones have a thin plastic membrane (a diaphragm) that initially receives the vibration from sound waves. Fixed underneath that membrane is a circular wire coil called a “voice coil” that floats in a magnetic field created by a permanently fixed magnet. The motion created by the vibrating membrane carries over to the voice coil and as that voice coil moves in its magnetic field, it creates a unique electric signal depending on the types of vibrations picked up by the membrane.
Condenser microphones also contain a thin membrane (diaphragm) this time made out of very thin metal or sometimes metal-coated plastic. Behind this membrane there is a small pocket of empty space between the membrane and an electrically charged back plate, known as a capacitor or a condenser (this is where this type of microphone gets its name). Because the back plate is electrically charged and the membrane is either thin metal or coated with metal, there is a magnetic field that is created in the space between the two surfaces. As sound waves cause the membrane to vibrate, the motion of the membrane and the movement in the electric field create the electric signal.
Now that we know how dynamic and condenser microphones differ from one another, we can try to understand how those differences create variations in the characteristics of each type’s sound. In theory, the diaphragm of a dynamic microphone has the capability to move more than the diaphragm of the condenser microphone. Does that mean that a dynamic microphone can handle louder signal? Yes, but not without consequences.
Since the membrane on a dynamic microphone can move more freely, it has the capability to generate a stronger electric signal to send through the cable. Remember that the energy is created when the diaphragm moves relative to the sound waves it receives. This causes the voice coil to move within its magnetic field. As this coil moves through the magnetic field, energy is created.
The diaphragm on a condenser microphone is aligned parallel to its back plate and they are placed extremely close to one another. As sound hits the diaphragm, it vibrates back and forth and the space between the diaphragm and the back plate changes rapidly. This distance change is interpreted as sound signal. The back plate and the diaphragm must have opposite magnetic charges in order for this technology to work. As such, condenser microphones either have a built-in battery or require power from the mixer. This power is known as phantom power. Also, the technology that combines a diaphragm with a back plate is called “capacitor” technology, but it used to be called “condenser” technology. This is where this type of microphone gets its name.
Currently, microphones are so advanced and the market is so competitive that most quality condenser and dynamic microphones have such similar stats that they’re almost entirely interchangeable and the differences in sonic characteristics have almost become theoretical. This is why as I stated earlier almost every sound engineer has a manifesto on why each mic type might be better suited for one thing or another even though they directly contradict one another.
Theoretically, the transducer technology of the condenser microphone lends itself to applications that require more sensitivity and precision. This is because the ability of the magnetically charged diaphragm and back plate to move with such precision can create a much more defined nuanced signal. As such, condenser microphones respond better to higher frequencies and capture the attacks of sounds more precisely than dynamic microphones.
The construction of a dynamic microphone does lend itself to be more suited to capture louder more intense signal without loss in precision. Think of it this way… If you’re a singer in a rock band that is constantly shouting into the microphone, you’re going to want to use a dynamic microphone because its diaphragm is more rugged and can handle more intense sound pressure. If you are a singer in a rock band and you want to capture the sound of your yell in a room, you might use a condenser microphone placed several feet away from yourself and you’ll capture a more nuanced detailed signal of what your voice sounds like. You can our microphone specifications guide for some more technical information if you’d like.
Other dynamic vs. condenser considerations
The transducer technology on a condenser microphone can be described as flimsy and fragile. If you’re constantly setting up and tearing down every day as your band tours from one venue to another, then dynamic microphones are for you. You’re going to want microphones that you can toss into a bucket and know that they’re going to be just fine.
If you’re going to be performing in a concert hall where there will not be much ambient noise and the precision of the sound is the most important thing, you’ll want to use condenser mics as they will pick up even the most detailed signal. Condenser mics are most commonly used in the studio as they are the most controlled environment where precision is most important.