Getting Started in Live Sound: Microphone Basics

Getting started in sound reinforcement can seem daunting. Tech talk sounds like a stream of random letters and numbers (and nicknames for numbers). Fortunately, with a basic understanding of how sound systems work, and the tools of the trade, you can learn to achieve good sound. The tech talk takes longer to master and arguably matters less.

To begin with, nearly every PA application requires a microphone. Knowing the general types of microphones and what they are best for can be helpful even if you find yourself mixing on a different system with mics with which you are unfamiliar.

The most common type of microphone used in live sound is the dynamic mic. These are generally very durable and do not require a power supply or phantom power to operate (phantom power is a voltage supplied to the microphone from the mixer through the microphone cable and is typically 48 volts). Depending upon the application, dynamic mics can come in a full range of polar patterns (the direction in which the microphone picks up sound), but the vast majority of mics you'll encounter will be cardioid (unidirectional). This simply means that the mic is designed to reject sounds coming from the rear. By facing the back of a unidirectional mic towards your monitor speaker and the front towards your singer, you can get a stronger signal with less chance of feedback. Dynamic mics have two main categories: instrument and vocal.

Instrument mics feature maximum sensitivity and a strong proximity effect to help keep other instruments from leaking into the channel. A common convention is to make instrument mics flat-screen since no pop filter is needed.

Vocal mics are often very similar to instrument mics but have a built-in windscreen/pop-filter to help prevent plosives and wind noise. Because the element is farther from the source, vocal mics have a slightly different frequency response than instrument mics. Sometimes this might be helpful to know if you're struggling to get an instrument to sound good; switching to a vocal mic may change the emphasis. Likewise, you can use instrument mics for singers if it flatters their voice, but make sure to add a foam windscreen to catch the plosives and reduce excess proximity effect.

Condenser mics are more frequently seen in recording studios, where they are favored for their ultra-wide dynamic range and high sensitivity. But a complex rig of screens and shields is often added to avoid picking up the faintest noises in the studio. Condensers require power to work, provided by batteries or phantom power from the board or external power supply. Sometimes condensers will be useful in live situations such as choir or instrument ensembles when the objective is to capture a number of performers on a single channel.

Carvin Audio UX1200MC Wireless Handheld Microphone System

Wireless handheld mics are almost exclusively vocal type with a unidirectional polar pattern and internal windscreen. The key with these (and all wireless systems) is to insist on new batteries for every performance and avoid outdated discount store batteries. If you cover the battery's contacts with blue tape after the gig, you can safely store them for use in non-critical situations such as rehearsal.

Specialty mics may be designed specifically for mounting on a particular instrument.  Also among specialty mics are the headset and lavaliere mics that broadcasters, actors, and public speakers use. These most often have omnidirectional polar patterns to keep the speaker's sound as natural as possible. Take some time to learn exactly how these should be fastened and concealed in order to achieve transparent sound and a minimum of unwanted handling noise. These microphones also require different EQ settings than that of a handheld vocal mic to achieve natural sound and eliminate feedback.

Whether you are a musician or you aspire to work as an engineer, knowing the basic types of microphones will be essential. Once you understand the types and you start learning which category a specific model fits into, you will be able to mix in any situation with confidence.

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