How To Choose a Microphone

• Posted on 8 February 2022
• By Tone Stephens
• 0

A quick and easy guide to understanding different types of microphones and which one may work for you.

Why are there so many different microphones? So many options to choose from, there’s: dynamic, condenser, ribbon, fet, tube, to name a few. With as many different pick-up(polar) patterns to match: bi-directional(figure 8), unidirectional, cardioid, omnidirectional, hyper-cardioid, super-cardioid. Why do any of these variables matter? I plug a mic in sing or play into it and it’s heard be it over the airways, on my recording, or at my performance. What's the difference? I don't have the time or budget to figure it out. So what do I do?

Microphones, a topic that's very near and dear to my heart. Also quite possibly one of the most heavily debated topics among musicians, live sound engineers, and studio engineers. They're either seen as a means to an end or a pivotal role in the creative process. For me, I fall in both veins but tend to lean more towards the pivotal for creating. That said it really depends on the application and the overall scope of the circumstance. If I'm going to be in a club/bar atmosphere several nights a week I need my mics to be rugged, If I'm working with an orchestra I need my choices to reflect the delicacy of the ambiance needing to be captured. No matter the situation I ultimately want the best sonic performance I can get.

So how do I get there? It’s funny much like most people, the first mic I purchased came from the recommendation of the person behind the counter at my local music store. I needed a vocal mic for live performance and I was handed the, at that time, most popular live vocal mic. The mic used by this person and that person. While these details of who has used it, and how long it’s been used by the industry are important. There are also other details that outweigh the popularity purchase point.

You’re an individual, unique and that's what makes your music stand out in the sea of creativity. The timbre of your voice, the genre of music you play, the instrument/s that make up your sound. These are the idiosyncrasies that when you’re aware of them and can communicate them, can lead you to the proper choice of microphone/s.

What is a Microphone?

Webster’s dictionary defines a microphone as, an instrument whereby sound waves are caused to generate or modulate an electric current usually for the purpose of transmitting or recording sound.

In a dynamic microphone, sound waves hit a diaphragm that vibrates, moving a magnet near a coil. Condenser microphones use a pair or more of charged metal plates, one is fixed (the backplate) and either one or two other plates on either side of the fixed plate (the diaphragm). A fixed plate and a single diaphragm form a cardioid microphone pattern. A fixed plate and dual diaphragms, one on either side of the fixed plate form an omnidirectional polar pattern. A ribbon microphone consists of a ribbon made of light metal that gets suspended between the poles of a magnet. As the ribbon vibrates the movement forms a voltage from the interaction of the ribbon and the magnets which is then received by contacts connected to the ends of the ribbon.

What is a Polar Pattern?

A polar pattern simply describes the directional sensitivity of a microphone to sound waves arriving from multiple directions to its center axis.

The most common microphone polar(pick-up) patterns are cardioid, omnidirectional, and bidirectional(figure 8). Cardioid pattern microphones have the highest sensitivity to sound at the front and the least at the back. Omnidirectional microphones pick up sound evenly from all directions. Bidirectional pattern microphones pick up sound waves predominantly from the front and back of the mic, but not the sides at a 90-degree angle.

Why does all of this polar pattern stuff matter? When you’re micing a performance whether it’s live or being recorded. Taking into consideration other sound sources or reflections of the original source in the space it is in is important to the quality of the reproduction of the source/s. Ex. If you're in a club you'd want to use predominantly microphones that have more direct patterns so as to not have tons of bleed from the other sources. on a big stage in a big space like an arena, a blend of patterns depending on the source can produce a much fuller sound. Ex. micing a drum kit you would generally use cardioid pattern mics on all the skins(drums with heads) and omnidirectional mics over top of the cymbals (overheads), this allows you to capture the drums individually and then blend the overheads in to add depth to the sound of the full kit because the omnidirectional mics are picking up sound waves from all directions equally.

Please Explain Microphone Frequency.

With all of the technology pieced together to allow a microphone to capture sound waves, these components are put together in a manner that can either capture the sound as naturally as possible or can modulate the sound to add or take away from the tonality of the natural source. The spec charts that come with microphones such a valuable resource when it comes to choosing a microphone.

Remember microphones are the tools in the audio signal chain that come directly after the original source. How a microphone supports the end result of the quality is key. Let me briefly explain frequency, frequency also referred to as EQ is the rate at which the source being captured is causing the soundwaves to vibrate/resonate. Slower vibrations form what we perceive as bass, faster vibrations are treble.

So many words are used to describe the frequency range each source creates. Words like pitch, warm, bright, dark, etc. if you’ve ever been to an orchestra performance you hear them tune their instruments to the key of A which is also the pitch/frequency of 440khz. One of my favorite things to do as a sound engineer is to geek out with artists and analyze the key the song is in and break down the range of the sources that each instrument fall in and how they contribute and detract from the arrangement.

Microphones are such a broad topic and much like building a mix, these choices can be subjective so for a continuation of this topic i will be uploading some conversations from seasoned engineers and their input lists.