• Donny

How does a microphone work?

Updated: Jun 23, 2018

And why do I care?

Hi there---second in a series of blogs designed to help inform first time #microphone buyers, or hobbyists what they need to know to get the most out of their gear.

Knowing how a mic works will help you understand why certain mics work better in some situations than others. Kick drum mics don't work very well for acoustic guitar or piano for example. Right here I have to say that rules are made to be broken and mics are colors to paint with so realize that experimentation rules in the studio, yet you often find certain mics being used certain ways a lot, as one would expect---norms happen for a reason.

Let's break down the categories. Dynamic, Condenser, and Ribbon are the three most common types.

Two of the most common mics in the world are the Shure SM-57 and the SM-58. Both models have sold millions for decades with almost no change to their design. They are perfect examples of what's known as a "dynamic" mic. These mics have a magnet and a coil of wire just like a speaker in reverse. Plug your headphones into your guitar amp input jack and holler into the phones you will have used the speakers in your phones backwards as a mic instead of a speaker. It works! Try it sometime just for ducks.

Internal diagram of microphone

Dynamic mics can take a LOT of sound before they distort. You can get loud. Dynamic microphones with a large diaphragm, called appropriately enough large diaphragm dynamic mics, respond well to bass frequencies and are often used as kick drum mics. They go low, they can take volume so---how about that? They work on a kick drum rather well. The hardy nature of the design lends them for use in live PA settings as well.

Condenser mics are much more sensitive and use a capsule design that relies on a tightly tensioned mylar diaphragm often sputtered with a very thin layer of gold, that reacts to a back plate that carries a charge. The two react--you get signal.

Diaphragm of large diaphragm microphone

The sensitive nature of these designs makes them ideal for vocals. Detail and clarity are captured well, the sound is big and pleasing. These mics were very expensive to build until around the 1990's when condenser capsule technology found it's way to China and the market exploded with affordable microphones.

Ribbon mics are famous for their warm softer sound. Ribbon mics are very often used on electric guitar amps because they help avoid a brittle zizzy sound. Yes I said zizzy. Sue me. Ribbon mics tend to respond less to the higher range of sound so less high---warmer sound. Bam.

Ribbon Microphone Diagram

I'll keep on with more soon.

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