USB or plugpack powered
Line level output
Although most PCs have a microphone input for recording, these
inputs are for basic electret microphone types only. Electret microphones are
typically used in headsets and are generally of low quality.
Similarly, some MP3 players include an internal electret
microphone for recording but again the quality is limited. These players often
also include a line input, to accept external audio signals.
Using an electret microphone will generally be satisfactory for
recording brief announcements and reminders. However, if you want really good
sound quality, a professional microphone will be required. This type of
microphone will also be necessary when the microphone needs to be more than just
a metre or two away from the computer or MP3 player.
Why are they better
Fig.1: this diagram shows how the Balanced Microphone Preamplifier is connected to a computer. Power can come either from a USB port or from an external DC plugpack supply (see text).
So why do the professional microphones give better sound than
low-cost electret microphones? There are several reasons.
First, professional microphones use a high-quality microphone
element that has a smooth frequency response plus low noise and low distortion.
Typical low-cost electrets do not have a smooth frequency response but a
response that peaks around the mid audio frequencies. And while low-cost
electret microphones readily detect handling and breathing noises, professional
microphones are designed to minimise this problem.
Professional microphones also have a tailored pickup response
that is more sensitive towards the front of the microphone than to the rear.
This lack of sensitivity towards the rear helps prevents unwanted noise
Another advantage of professional microphones, particularly for
voice recordings, is that they give more depth to the sound. That's because the
bass response is more pronounced when the microphone is brought close to the
mouth. A headset electret, on the other hand, usually has a poor bass