If you have ever recorded anything in a studio you probably used a condenser microphone rather than the popular dynamic microphone.
How a Condenser Microphone Works
A condenser microphone is also known as a capacitor microphone because the key element in one of these microphones is a capacitor. A capacitor consists of two metal plates that are very close together. The backplate is often made of brass and is in close proximity to the diaphragm (or other plate) . The diaphragm is often made of gold-sputtered mylar or any other very lightweight metal. This lightweight membrane must be electrically conductive for the microphone to work.
The condenser microphone converts sound into an electrical signal when parts within start to vibrate causing the voltage across the capacitor to change. Specifically, sound waves hit the capacitor and cause the electrically charged plates to move closer together or further apart, essentially changing electricity into sound!
You may be surprised to find out that the voltage between the two plates produces an extremely small current because although the voltage is strong the capacitor is much too small to store much energy. The capacitor requires some help from the outside world. This is where the impedance converter comes in. An impedance converter allows the signal to become strong enough that the microphone will actually function.
The fact that the condenser microphones need an external power source is not a big deal anymore. Pretty much all condenser microphone inputs come equipped with P48 phantom power which allows a signal to be sent directly from an audio interface into the microphone. In fact it is difficult to find a microphone now without this capability as P48 phantom power is now the international standard.
Superior Sound Quality
What are the advantages to using a condenser microphone over a dynamic microphone? The diaphragm in a condenser microphone is much lighter and more accurate making the quality of sound much higher. Condenser microphones are known for their wide frequency response and extreme sound sensitivity. This is because the diaphragm is able to detect very subtle variations in air pressure. Of course, there is a huge variety in the quality of condenser microphones. An inexpensive microphone, no matter what type, will offer much lower sound quality than a high quality version.
Powering Condenser Microphones
It used to be quite inconvenient to obtain the external power needed for a condenser microphone. Neumann’s earliest microphones required each microphone to have its own large PSU box and multi pin cable. From 1928 until the late 1960s this was the way it was. If people wanted the high quality sound that was possible with a condenser microphone they needed to put up with the inconvenience of the external power box. This all changed in the ’60s when transistor technology took over. P48 phantom power was created and very quickly became an industry standard. P48 power was able to supply power to condenser microphones without affecting the dynamic microphones that do not need external power.
The oldest way to power a microphone is by using tube technology. Amplification using tube technology requires a vacuum tube to boost the signal from the capsule. Although this is a vintage method of powering a microphone many people think it creates the best sound and it is becoming popular again.
Some examples of Saramonic products that have phantom power are the SmartRig+ 2 channel audio interface, SmartRig II XLR Microphone & Guitar adapter, and the UwMic9 TX-XLR9 Plug-On UHF Microphone Transmitter.
Types of Condenser Microphones
Condenser microphones come in two different types - small diaphragm and large diaphragm. There are two different types of condenser mics: small and large diaphragm.
Very often people that are recording vocals or instruments will want a Large-diaphragm microphone because many people believe that the Large-diaphragm microphones allow for better sound at low frequencies than small frequency mics. This, however, is a myth as small diaphragm mics are actually far better at reproducing all frequencies evenly. One advantage of the LDM is that they warm up the sound of whatever is being recorded. No matter which condenser mic you choose, be aware that they are very sensitive and they will distort the p and sh sounds if you do not use a pop screen.
If you are recording yourself playing a guitar or violin and you need a strong, wide frequency response you will want to get the Small-diaphragm microphone. SDM’s are also the best choice for concert taping.