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Choosing the Right Microphone

As we discussed in the previous tutorial, there are many different types of microphone in common use. The differences are usually described in two ways: The technology they use (e.g. dynamic, condenser, etc) and their directionality (e.g. omnidirectional, cardioid, etc). In addition, microphones have a number of other characteristics which need to be taken into account.

When choosing a microphone, the first thing you will need to know is what characteristics you need. After that, you can worry about things like size, brand, cost, etc.
Note: If you haven't done so already, you might like to do some groundwork and read how microphones work first.


Things to Consider

Work through each of these characteristics and determine your needs.

Directionality

Decide which type of directional pattern best fits your needs. Remember that it's usually better to use a less directional mic in a position close to the sound source, than to be further away using a hypercardioid. For more information see microphone directional characteristics.

Frequency Response

Make sure the mic's frequency response is appropriate for the intended use. As a rule of thumb flat response patterns are best, but in many cases a tailored response will be even better. For more information see microphone frequency response.

Impedance

The rule of thumb is: Low impedance is better than high impedance. For more information see microphone impedance.

Handling Noise

Remember that the diaphragm works by converting vibrations from sound waves into an electrical signal. Unless the microphone has some sort of protection system, the diapragm can't tell the difference between a desirable sound wave vibration and any other sort of vibration (such as a person tapping the microphone casing). Any sort of vibration at all will become part of the generated audio signal.

If your mic is likely to be subjected to any sort of handling noise or vibration, you will need a mic which will help prevent this noise from being picked up. High quality hand-held mics usually attempt to isolate the diaphragm from vibrations using foam padding, suspension, or some other method. Low quality mics tend to transfer vibrations from the casing right into the diaphragm, resulting in a terrible noise.

Note that lavalier mics don't usually have protection from handling noise, simply because they are too small to incorporate any padding. It is therefore important to make sure they won't be moved or bumped.


Purchasing a Microphone

If you can afford it, it makes sense to buy a range of microphones and use the most appropriate one for each job. If your budget is more limited, think about all the different things you need to use the mic for and try to find something which will do a reasonable job of as many of them as possible.


Comparisons

In the end, sound is quite subjective. You really want a mic which will provide the sound you like. A good idea is to set up a contolled test. Record the same sounds using different mics, keeping all other factors constant.

Make sure you are comparing apples with apples; for example, don't compare a hand-held cardioid and a shotgun in the same position. If you do want to compare these mics, make sure each is placed in its optimum position.


Next Page: How to Position a Microphone

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