Condenser Microphones and Dynamic Microphones – What’s The Difference?
The differences between condenser microphones and dynamic microphones can be confusing, so here’s a mini-guide…
Microphones can be divided into two broad groups (ignoring ribbon mics for the time being…) – condenser microphones and dynamic microphones. Both have a broad range of uses in the studio and live environment, but there are key differences in tonal characteristics and in the way that each group of microphones works.
To help understand the differences between them, here’s a guide to how each works.
This group of mics is sometimes referred to as moving coil mics. This name reveals much about how they work. They can almost be considered as a loudspeaker in reverse.
A diaphragm is attached to a thin coil of wire. This is in turned mounted in the space in front of a magnet, and wired to the magnet. When the air around the diaphragm vibrates due to sound, the diaphragm moves, as does the coiled wire. As this is in the field of a magnet, it generates an electrical current. This is transferred via the mic cable to the mixer, amp or other audio device, for the process to be carried out in reverse.
Because of the way they are constructed, dynamic microphones are very robust- the SM58 legendarily so. This is one of the reasons that they are very well suited to live situations. They can also withstand very high sound pressure levels (high volumes) and are more resistant to feedback, which also makes them a good live choice.
However, the reason for this feedback resistance is also responsible for its biggest drawbacks. Dynamic microphones are less sensitive than condenser microphones, in particular, to higher frequencies.
This is because the coil of wire has a relatively high mass, and thus takes a bit of energy to move. Lower frequencies of sound have higher wave energy than higher frequencies. So whilst high frequencies may leave the coil unmoved, lower frequencies will move it. Because it takes more energy to move, the coil also moves more slowly. This means that sound with fast transients (the changes between different volume levels) can lose some of their definition.
This is not necessarily a bad thing. In situations where loud sources without lots of very high frequencies are to be mic’d up and recorded, the dynamic microphone is ideally suited. Drum kits, guitar amps and more can all benefit from dynamic mics.
- Incredibly robust
- Feedback resistant
- Can handle high sound pressure levels with less risk of damage to the mic
- Ideal for many live situations
- Ideal for recording many very loud sound sources
- Generally less expensive than condenser microphones
- Do not require external power
- Less sensitive than condenser microphones
- Poorer high frequency response than condenser microphones
- Typically, poorer dynamic range than condenser microphones
In the last 10 years or so, condenser mics have moved from being the preserve of pro studios or home enthusiasts with very deep pockets, to being far more common and affordable. Whilst there are many varieties of mics of this type, they are possibly at their most recognisable as the large cradle mounted mics seen suspended from the ceiling of recording booths in pop music videos (ahem!)
In operation, there are major differences between condenser and dynamic mics. The diaphragm in a condenser microphone is a far thinner, plastic film that is usually plated with gold (though nickel is also sometimes used). This is mounted in close proximity to a conductive backplate.
A voltage is applied to this backplate either via an external power source (usually +48V Phantom Power- a feature on most mixers and audio interfaces), or in the case of some microphones, via an internally fitted battery.
The diaphragm and charged backplate create a capacitor. Without getting too bogged down in technicalities, as the air around the diaphragm vibrates with sound, the diaphragm moves closer and farther away from the charged plate. This causes the charge across the plate to change according to its distance.
This changing electrical current is transferred via a cable to a mixer or recording device, to be converted back into audio by another transducer.
There are several major advantages to condenser microphones. The lower mass of the diaphragm used, and its close proximity to the charged plate means that it is far more sensitive and detailed. And, as it takes less energy to move, it preserves far more of the higher frequency content of a sound source.
This sensitivity results in higher dynamic range. The improved high frequency response makes condenser microphones ideal for recording anything that requires the sparkly high frequencies to preserved: vocals, acoustic guitars, drum overheads, pianos and strings all benefit from this, though there is generally a condenser mic suitable for most sources.
However, condenser microphones are far less robust than dynamic mics, and require handling with more care. In addition, many (though not all) cannot handle the sound pressure levels that dynamic mics can without risking damage.
The higher sensitivity means that many condenser mics are not ideally suited to live situations- though nowadays, most manufacturers produce handheld condenser microphones designed specifically for live use.
- More sensitive
- Excellent high frequency response
- Detailed sound
- Faster transient response
- Generally, higher dynamic range
- More fragile
- Often have lower maximum sound pressure levels (cannot be used on very loud sources)
- Requires a power source (either phantom power or internal battery)
- Increased sensitivity means that most are better suited to studio situations
- Generally more expensive
With mics, there are no rules- as Joe Meek once said, ‘if it sounds right, it is right’- so the above is just a guide. Hopefully, this has illuminated some of the more confusing aspects of how they work.