Introduction to Dynamic and Condenser Microphones
This article is a basic introduction to the workings and uses of two of the most popular types of microphone – the dynamic and the condenser.
What are microphones?
Microphones are basically transducers – that is an object that changes one form of energy into another. Just as a light bulb changes electrical energy into heat and light, a microphone changes differences in air pressure (acoustic energy) into electrical energy (Alternating Current) that can be recorded.
What is a dynamic Microphone?
Dynamic mics are the standard general-purpose mics like the type you see people singing into on top of the pops. The design of a dynamic microphone is very simple and they have few moving parts. This makes them quite rugged and able to withstand high volumes and abuse from hairy roadies.
Dynamic microphones work using the electromagnet principal. The diaphragm vibrates when sound waves hit its surface and this in turn moves a coil of wire back and forth past a magnet. This generates an electrical current that is sent down two wires and out of the mic.
As mentioned previously, dynamic microphones are able to withstand high SPLs so are ideal for recording loud guitar amps and drums. Their resistance to damage also makes them great for the wear and tear of live use. Unfortunately because they are rugged and have a fairly thick diaphragm that is attached to a wire coil, dynamic mics can’t pick up high frequencies well. They also tend to have a bumpy frequency response, which means they colour the sound.
Examples of dynamic microphones:
- Sure SM57 – Good general purpose instrument mic.
- Sure SM58 – Great for live vocals.
- Sennheiser MD421 – Another good general purpose instrument mic.
- AKG D112 – Designed specifically for kick drums and bass frequencies.
What is a condenser Microphone?
Condenser microphones are much more expensive and fragile than their dynamic brethren. They can generally record a wider frequency range and have a flatter frequency response. Condenser mics also need power either from a battery or in the form of “phantom” power (+48v) from a mixing desk or mic pre-amp.
Condenser mics work on the principal of capacitance. They have two plates that have a voltage between them. One of the plates is the diaphragm that is usually only a few microns thick and sputtered with gold to make it electrically conductive. The second plate is called the backplate. This is fixed in position and usually has holes drilled into it to allow air to move freely. Condenser microphones generate a signal when the diaphragm vibrates and moves closer to and further away from the backplate. A fixed charge is placed across the two plates and so when they move closer the capacitance increases and when they move away capacitance decreases. This produces an electrical current that can be recorded.
As condenser mics have much thinner diaphragms, they can pick up much higher frequencies and quieter sounds. This makes them ideal for recording just about anything in the studio. Vocals, guitars (acoustic and electric), cymbals and pianos will really come to life when recorded with a condenser microphone. Care does need to be taken when using them for micing up loud instruments as they can distort with high SPLs. Many condensers have a pad switch that makes them less sensitive and less likely to distort.
The only real downsides of condenser mics are their cost and fragility. They can set you back anything from £100 to £3000 and up. Due to their design and extremely thin diaphragm, they are not very robust. If you drop a condenser that may be the last time you use it! For this reason (and the fact that they will pick up everything) they are generally not used as much for live work.
Examples of Condenser microphones:
- AKG C414 – Excellent all round studio microphone.
- Neumann U87 – Excellent, but pricey all round studio microphone
- Rode NT2 – Great budget microphone.
Conclusion
If you’re looking for a general-purpose microphone for your home studio, a decent quality condenser mic would be a good option. You can pick up a very respectable performing condenser such as a Rode NT1000 for around the £160 mark. If your budget can stretch to it, AKG’s C414 is a great, versatile, multi polar pattern mic for around £600.
For live use Sure’s dynamic SM58s are great vocal mics and their SM57s will do your amp proud. For instruments that need higher frequencies to be picked up, AKG’s C1000s is a solid performer and is surprisingly rugged for a condenser.
Related article – Microphone polar patterns explained.
Recommended reading:
Jon Maskrey
24 February 06
commenting closed for this article