Recording Microphone Buyer's Guide

Introduction

The world of microphones can be a daunting one as there are literally hundreds of options to choose from. While they all capture sound, they are not created equal. Each microphone is tailored to a specific application and is designed to pick up sound from a specific direction. There are also different technologies involved which make some more sensitive to sound than others. That being said, there are also similarities between each type of mic. For one, they all convert the sound of instruments and vocals into an electrical signal that can be amplified. Let’s first take a look at some of the more popular types of microphones.

Handheld Dynamic Microphones

Sennheiser e945 Dynamic Vocal Microphone

Handheld Dynamic Microphones are known for being durable with the ability to handle abuse (within reason). They consist of a diaphragm, voice coil, and magnet. Sound waves move the diaphragm/voice coil in a magnetic field to generate the electrical equivalent of the acoustic sound wave. With no need for additional circuitry, their design is extremely rugged. Another key trait is being able to withstand high SPLs (sound pressure levels). This means they can capture really loud sounds without distortion, making them a favorite for drums, guitar amplifiers, and rock vocals. (See our selection of Dynamic Instrument Microphones) On the contrary, they don’t handle instruments with a wide dynamic range as well as condenser mics, which are known to be more sensitive and authentic in projecting the finer details of a sound. Since they don’t accurately represent high frequencies, they often impart a “gritty” sound to the signal.

Condenser Microphones

Behringer Condenser Microphone

Condenser Microphones use a conductive diaphragm and electrically charged backplate that captures the sound. They contain active circuitry which requires a battery, or the use of phantom power supplies, a power source transmitted from a microphone preamp to the mic through XLR microphone cables. Due to their sensitivity, condensers more faithfully capture the transients and nuances of instruments and vocals.

Traditionally, condensers were not considered as durable as dynamic mics but most modern condensers are very robust and can be used in a live setting with great success. The increased sensitivity does require careful placement and gain control so that the signal does not distort. Condensers can sound more natural, but can also sound harsh if placed too close to a high transient source (such as a cymbal).

dbx RTAM Reference Condenser Microphone

RTA microphones (Real Time Analyzing) are condenser microphones designed for measuring a room’s acoustics. They typically employ an extremely flat frequency response. This allows them to accurately capture signals such as pink noise and then when used in conjunction with a speaker management system, can help to EQ speakers to sound best for that particular room.

Ribbon Microphones

Cascade Ribbon Microphone

Ribbon Microphones operate similarly to dynamic microphones, but feature a thin piece of metal (the ribbon) suspended between two magnetic poles. They too need no additional circuitry to operate, but unlike other moving-coil microphones, they are not rugged. This is due to the ribbon element being so thin, it can be deformed by strong blasts of air. Also of note, phantom power can harm ribbon mics.

Ribbon microphones excel in their warmth and good response to low frequencies. Since ribbon mics are relatively slow to respond to an auditory signal, it tends to soften the initial attack of an instrument. This lends to rounder, richer tones, which shine on percussion and piano.

Diaphragm Size

Avantone Pro CK1 Small Diaphragm Microphone

Large diaphragm condenser mics have a diameter of one inch or larger, while a small diaphragm condenser mics are under one inch. This little difference in design has a huge impact on the mic’s performance.

Large diaphragm mics are typically more sensitive which results in a higher signal voltage. Think of how a large sail moves a boat easier than a small sail. Sound waves have a similar effect on the microphone diaphragm.

Large diaphragm condensers also provide a stronger signal above the noise floor of the mic’s electronics. This makes large diaphragms a better choice for recording quiet instruments without adding noise from the mic. This same reasoning makes small diaphragms excel as ambient room mics. In addition, the smaller mass of a small diaphragm allows them to respond better to cymbals and other instruments with extreme high frequencies.

Polar Patterns

A polar pattern represents how the mic is designed to pickup sound. Its important to understand them in order to properly capture your vocals and instruments. This is especially true when multi-miking drums as you may want certain mics to pick up the sound of the entire kit, and others to focus on one particular drum or cymbal.

The following are the three most popular types of patterns.

Cardioid Polar Pattern

Cardioid: This pattern picks up best from the front and sides while completely rejecting from the rear. Cardioid microphones are great for vocals, guitar cabinets, and solo instruments such as brass and woodwinds.

Microphone Pattern Diagram

Omnidirectional: Omni mics pick up well from all sides. They are useful for situations in which capturing both the direct sound and the room ambiance is wanted. Headset and lavalier (small clip-on) microphones are typically omni so that they can pick up the human voice without being right in front of the speaker’s mouth. In addition, RTA microphones are omnidirectional.

Figure 8 Polar Pattern

Figure 8 (bi-directional): Picks up well from both the front and rear, rejecting anything coming from the sides. They can be used for a duet of vocalists, or are perfect for MidSide or Blumlein stereo recording techniques.

Some microphones feature flexible polar patterns that can be easily changed via a switch on the microphone. They’re great to have in your mic locker as they work for a variety of applications.

About the Author - Headsnack

Headsnack has specialized in creating training materials for some of the biggest names in music gear retail, for over 12 years. His Training Snacks brand has produced several pro audio category and product training segments which can be found on YouTube and in written form on AmericanMusical.com.

As a musician, Headsnack is a positive-minded producer, performer, and lyricist who specializes in electronic beat-making and writing hilarious songs that mock humanity. His music, which has been described by fans and reviewers as everything from “conscious hiphop” to “next-level pop”, has been licensed to several artists, labels and films including Public Enemy, Sky Mall, and the Independent Film Channel. His viral-style YouTube videos have garnered over 60,000 views and he has also DJ’d for various clubs and parties for over 15 years.