Like so many things in audio we naturally gravitate towards the things, we perceive as the “perfect” tool to use for a task. As a key player in your podcasting arsenal, the microphone is the tool you’ll often obsess over. Let’s take a minute to look at the basic types of microphones and see how obsessing over perfect quality can often lead to less-than-perfect results.
Regarding microphones, we have two basic choices: the dynamic and the condenser. The dynamic microphone takes the sound energy in the air and transfers it with a thin diaphragm and a coil of wires into a small amount of electrical energy. This type of microphone is the older of the two designs and has a couple of inherent downsides. First, it very rarely reproduces the entire audio spectrum humans can be capable of hearing, and second, the dynamic microphone needs some strong preamplification to turn the minuscule amount of electrical energy (from a source such as normal conversation) into something usable.
The condenser microphone still has a diaphragm that moves in relation to sound energy but then handles things differently. The condenser microphone has a solid metal plate behind the diaphragm that is also layered with a very thin layer of metal. The slight changes in distance between these two metal plates create the slightest amount of electrical current, and this is amplified by an internal circuit powered by “phantom power” the microphone receives through the mic cable from the mic preamp. As the diaphragm of the microphone is not connected to a coil to produce an electric current such as a dynamic microphone’s is, it is much lighter and much more sensitive in both the level of audio it can capture as well as the range of frequencies.
On paper, the condenser microphone has the clear advantage of being the “better” tool for the job. If you look at the frequency response chart of a well-loved dynamic microphone such as the Shure SM58 and place it next to almost any condenser you’d come to the conclusion that the condenser produces a more realistic reproduction of the source material over a much wider range of frequencies. But much like a Ferrari is a superior vehicle in almost every way to Toyota Camry, taking a Ferrari to the grocery store is largely overkill. The human voice resides over a much smaller part of the frequency spectrum so a dynamic microphone can handle those frequencies with ease while also not reproducing frequencies we don’t need (or want) such as the rumble of an air conditioner or the high-pitched whine of a computer fan or exaggerate every mouth noise you make while speaking. Some dynamics, such as the Electro-Voice RE-20 or RE-320, also reduce the phenomenon of the “proximity effect”, where the voice can become very bass heavy when the speaker is too close or thin when they move further away or to the side. This can make your audio file very hard to listen to and the levels vary wildly if you don’t practice the perfect microphone technique.
In summary, don’t be fooled by the frequency response graph of the condenser microphone and assume it will be the better tool for the job. Do yourself a favor and look for a good quality dynamic microphone for podcasting, there is a reason this is the type of microphone found in almost all radio studios.
