Do you need a dynamic or a condenser microphone? In this post, I’ll teach you the most important differences so that you can decide for yourself.
How Microphones Work
Let’s take a quick look at how dynamic and condenser mics work.
A dynamic microphone (or more specifically, a moving coil microphone) consists of a diaphragm, a coil, and a magnet. The diaphragm and the coil are attached to one another and the coil is wrapped around the magnet. When sound waves interact with the diaphragm, it causes the coil to move within the magnetic field of the magnet, resulting in an electrical current in the coil of wire.
A condenser microphone (sometimes called a capacitor microphone) consists of a diaphragm, a backplate, and an amplifier. The diaphragm and backplate are in close proximity to one another, with a bit of space between them. When sound waves interact with the diaphragm, the space between the diaphragm and the backplate changes, which varies the capacitance and results in an electrical current. The circuitry within a condenser microphone requires phantom power, which is usually supplied by the microphone preamp.
Thanks to the generally more rugged design of moving coil microphones, they are more durable against all sorts of wear and tear.
Take for instance the Shure SM58, which is known to be virtually indestructible. My SM58 has been dropped many times in the past. And although it has scratches and a dented windscreen to show for it, it still sounds pretty much the same as any other Shure SM58. There are some very rugged condenser microphones as well, such as the Shure SM81. But some condenser mics are more delicate and should be handled with care.
Max SPL, Sensitivity, & Self Noise
Generally speaking, the greater mass of a dynamic microphone gives it the ability to handle greater input levels. Dynamic mics generally have greater maximum SPL specifications, making them more suitable for recording extremely loud sources, such as trumpets and snare drums. On the flipside, condenser microphones are generally more sensitive than dynamic mics, which gives condenser mics an advantage when capturing relatively quiet sources. The sensitivity of a microphone describes the electrical output that can be expected at a given sound pressure level.
The Shure SM7B is known for its low sensitivity, meaning it requires more preamp gain to achieve an adequate signal level for recording. So, a Shure SM7B may not be the best option for recording very quiet sound sources, when compared to a condenser microphone with greater sensitivity like the Rode NT1-A.
The active circuitry within a condenser microphone will have some level of self noise, while a dynamic microphone is passive. However, this doesn’t necessarily mean that the condenser microphone will have greater self noise overall.
As Julian Krause pointed out in a video, when you take into consideration the lower sensitivity of a dynamic microphone, you may find that you’ll get a lower noise floor from a condenser microphone because less preamp gain is required. In any case, the stronger the signal level going into the microphone, the less the self-noise matters.
The polar pattern of a microphone describes how it reacts to sound at different angles. While an omnidirectional polar pattern picks up sound evenly in all directions, a cardioid pattern will pick up sound best from the front and reject sound from the rear. A sound directly in front of the microphone is considered on-axis. You can often expect a more extreme off-axis rejection from dynamic mics when compared to condenser microphones.
The polar pattern of a microphone can be used to optimize the rejection of room noise and also to increase the max gain before feedback. You just need to point the rejection point of the polar pattern toward the source of the noise you’re trying to reject. A tighter pattern also helps with reducing the impacts of an echoey room.
There are several polar pattern types available for dynamic and condenser microphones. Some condenser microphones even have multiple polar patterns that can be selected to suit each situation. For example, this Austrian Audio OC818 and LEWITT LCT 640 TS can be switched between cardioid, omni, and figure-eight.
Frequency Response & Transient Response
A condenser microphone will often have a more linear frequency response compared to a dynamic microphone. Don’t get me wrong here, these are just generalizations. Plenty of detailed and bright dynamic mics exist – including this Telefunken M80.
It’s best to look at the frequency response of a microphone on a case-by-case basis. If you plan to record various instruments for various types of music, you’ll probably want a variety of dynamic and condenser microphones with a variety of voicings.
Another sonic characteristic of condenser microphones is an improved transient response, meaning the microphone reacts more quickly to sudden changes in sound pressure level. You can even find differences in the transient response between small diaphragm mics like the Shure KSM141 and large diaphragm condenser microphones like the Rode NT1-A. In general, the lower the mass of the diaphragm, the quicker it can respond to transients.
Again, this doesn’t mean that condenser microphones are necessarily better than dynamic mics – just different. Choose a microphone that is going to give you the sound you want, whether that means precisely capturing every minute change in SPL or whether it means dampening of those details for a warmer recording.
Dynamic mics are generally cheaper to produce than condenser mics. If you’re on a very strict budget, you’ll likely get a lot more for your money when you go with a dynamic microphone.
For example, this Shure SM58 and this Audio-Technica AT2020 both cost about $100. It’s difficult to directly compare these microphones, because they each have their strengths. But I believe I got a lot more out of the $100 I spent on this dynamic microphone than the $100 I spent on this condenser mic.
Even though I now have several more expensive microphones, I continue to use this Shure SM58 – and will continue to use it for years to come, as it’s extremely versatile and durable. However, I rarely find myself reaching for the AT2020 because there aren’t many situations where it is the best choice now that I have some other mics to choose from.
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