Microphones can be a confusing area for the newly indoctrinated audio engineer. Dynamic and condenser microphones are the two main varieties Let's take a look at the fundamental differences and which sort you should choose for different recording applications.
Keep in mind the two following concepts when reading on:
- Frequency Response: the ability of the microphone to reproduce frequencies across the entire audible spectrum, 20Hz-20kHz.
- Transient Response: The ability of the microphone to reproduce the instantaneous amplitude of the sound source.
These are the work horses of the microphone world. They are rugged and will withstand the most horrific of abuse and traditionally withstand very high sound pressure levels, this is why they are the common choice for live applications.
Having said that, they also have a well earned place in the studio. Microphones like the Shure SM58 and SM57, and the Sennheiser MD421 have reached cult status as live and studio microphones, used for applications such as guitar cabinets, snare drums and congas, right through to vocals.
They are usually cheaper than condenser microphones, due to there simplicity of construction, but due to this construction they suffer from a reduced frequency response and transient response. However for some purposes this can be beneficial. For example, when using a dynamic microphone on a transient signal like a snare drum, the reduced transient response almost gives the effect of a natural compression, taming the initial attack.
From left: Shure SM58, Shure beta57, Sennheiser MD421, all well used!
Condenser microphones are likely to be the more common professional microphone that you may come across. Historically, they tended to be fragile in construction and lack the ability to withstand higher sound pressure levels in comparison to their dynamic counterparts. This isn't so much the case nowadays. Manufacturers are building their condenser microphones with all sorts of applications in mind.
The main benefit that condensers have over dynamic microphones is the extended frequency response and transient response. Keep in mind that they also require phantom power in order to function. This is usually not a problem as most credible interfaces will have phantom power as standard on microphone inputs.
Common well respected brands and types include the Neumann U87, Rode NT2 series, or SEelectronics Z3300a. The preceding varieties are large diaphragm (usually one inch diameter), yet they also come in smaller diaphragm types such as the Rode NT5 or Milabs VM44 Classic.
One disadvantage to condenser microphones is that they are usually more pricey in comparison to dynamics. The stated varieties can run from AU$250 (NT5) through to the thousands of dollars for the Nuemann U87.
From left: M-Audio Solaris, Rode NT2-A, Rode NT5
When Should I Use Which One?
The application of each type of microphone is an incredibly broad topic, but there are a few fundamental things to keep in mind. Ask yourself:
- Is the sound source LOUD?
- Does the sound source have a rich timbre (wide frequency response)?
- Does the sound source have a quick attack (short sharp transient, i.e. snare drum)?
If you answered yes to question one, then tradition would dictate that you should use a dynamic microphone. If you answered yes to questions two and three then a condenser microphone maybe your best bet.
This should serve as an introduction to the two main types of microphone, it is by no means a comprehensive rundown. Therefore, it needs to be said that there are many more factors that will contribute to the choice of microphone you use for a specific application. Things such as where the sound source will be placed in the mix, what sound you are trying to achieve, what budget constraints you have, and the list goes on. After reading all of this, remember, there are no rules. Just guidelines!
If you want to know more as I am sure you do, Adrian Try wrote a great article directing the reader to over 40 sites that can help you understand and choose microphones. You can find it here!