Before I begin this blog post, I just want to throw out a line to any musicians who would like to donate some music to my videos. I'll play your song underneath and around my little speeches and I'll give a shoutout and longer sample at the end. Feel free to shoot me an email or a message on any of the social medias :) Okay... now back to our regularly schedule broadcast.
The bass player in my band, Erik, recently connected me with a teenager who was interested in audio. After speaking with the teenager (we’ll call him Scott to protect the innocent) and his parents, I am starting to give him recording lessons! I’m excited about this new journey because not only does it help me in my quest for topics for this blog, but it also is teaching me a lot about… teaching. Cool!
In this week’s lesson with Scott, I want to teach him about the microphone. More specifically, the difference between the types of microphones. So let us begin with an overview. There are three types of microphones:
Dynamic (Moving Coil) Microphones
Condenser (Capacitor) Microphones
An important concept to be aware of before I go further is the concept of electromagnetic induction. The electromagnetic force is one of the universe’s four fundamental forces, just like gravity. Electromagnetic induction is the idea that magnetism and electricity are inextricably related because when a magnetic field moves, an electric field is created.
Accepting what I said above to be true, let’s talk about dynamic microphones. Inside a dynamic microphones there a thin membrane (diaphragm) attached to a coil. The coil is surrounded by a magnet. When sound moves the diaphragm, it also moves the coil by extension. The coil’s movement inside the magnet makes the magnetic field shift at the same rhythm of the sound, creating a small amount of voltage.
Next let’s talk about ribbon microphones which are actually very similar to dynamic microphones in how they work--not necessarily how they sound. Inside of a ribbon microphone, there is a thin sheet of metal surrounded by a magnet. Unlike a dynamic, the membrane/diaphragm is directly involved in the electromagnetic induction. When the sound hits the metal “ribbon” from the front or the back, the magnetic field moves to the rhythm of those sound waves and creates a voltage.
Finally, let’s talk about condenser microphones. "Condenser" is another name for "capacitor". A capacitor is created when two charged conductors (or in other words, materials that are conductive, like copper or gold), are close to each other. Condenser microphones are different than dynamic and ribbon mics because they create a voltage using a change in capacitance rather than a moving a magnetic field. So let me set the stage for you.
Inside of a condenser microphone, there is a thin metal diaphragm that moves when sound hits it. That diaphragm is attached to a sturdy metal plate. Alone, no voltage or current will be created because the metal plates aren’t charged. But… if you supply those plates with a little bit of voltage (AKA phantom power, 48V), all of the sudden the two plates form a capacitor. Now, when the diaphragm moves sympathetically with a change in air pressure when sound waves hit it, the capacitance changes and a small voltage is created.
Thank you mediacollege.com. Also, not shown in this diagram, you can substitute the battery with phantom power.
This concludes the blog on microphones! Much love to you all, and more posts coming next week!!