As my third semester at CSUMB starts to unfold, I am realizing how incredibly fortunate, happy, eager, and excited I am to learn, get my hands on a board, and make awesome music with some of the most awesome people ever!
The microphone has been a big part of my life since I was about 2 years old and I am almost ashamed to say that I had no clue how they even worked, apart from plugging it in, let alone how incredibly intense they are!
There is a huge, dynamic world condensed inside of each microphone that, when used correctly (or incorrectly in some cases), are so much more than just a way to record sound.
1.25.12
There are 3 kinds of microphones: Dynamic, Condenser, and Ribbon.
Transducer: Device that changes any one form of energy into another. Windmills, hydraulic pumps, solar panels, and even our ears are transducers!
Mics change air pressure, or sound in this case, into electrical signal. And every recording starts within a microphone that captures the sound.
When a conductor moves across a magnetic field, it creates a change in flux proportional to the movement. Air pressure can move conductors in magnetic fields and generate equivalent electrical signal.
The Carbon Microphone
They have narrow frequency responses and are rarely used today, but were used in telephones. The carbon granulates separate 2 plates that react to air pressure.
These kinds of microphones use a mylar diaphragm with a voice coil to achieve electromagnetic induction. They get their unique sound from voice coils which take energy to move and to stop. They can also handle high SPLs, or sound pressure levels, and are rugged in their construction making them really great for live application.
Condenser Microphones
These kinds of mics are based on the electrostatic principle. They have 2 polarized plates that create a capacitor out of the air between them, as the air pressure moves the plates closer together. Also, these kinds of microphones require an extra voltage boost called Phantom Power.
Phantom Power = +48 volts sent to the condenser microphone to give it that extra boost.
Some condenser mics are large, and some are small. Large diaphragm condenser mics are more common and have a 1 to 1.5 inch diaphragm and are capable of creating a variety of polar patterns.
Small diaphragm condenser mics have less than 1 inch diaphragms and are highly directional and sensitive in the higher frequency ranges.
Piezoelectro Microphones
These cool mics rely of natural substances that generate electric charge in response to pressure. They are used as boundary microphones and especially for acoustic guitars.
Polar Patterns
All microphones are directional. Every microphone has a front and a back end. The major polar patterns include omnidirectional, cardioid, supercardioid, hypercardioid, and figure of eight.
- Omnidirectional: Picks up sounds from all directions, is typically never used off-axis, and don't experience the proximity effect.
- Cardioid: Gets its name from its shape--a heart! This is the most common directional mic.
- Supercardioid: Gets sound from the back as well as from the front and wont accept sound at any angles from the back.
- Hypercardioid: Increased acceptance from the back and increased rejection from the angled back sides.
- Figure of Eight: Picks up sound from the front and from the back, but has a lot of resistance from the sides.
Frequency Responses
This is the quality that makes microphones sound unique. There is a proprietary hump that will hype the sound unnaturally at a certain point in the frequency. For example, the Shure SM57 is used to mic the snare drum because its proprietary hump hypes the perfect frequency where the snap of the snare lies.
Thoughts
In a few hours, my group (Kevin Lienhard, Collin Atkinson, Orion Navaille, Michael Glines, Nick Brumme, and I) will be completing our first lab designed to get our hands on a mic and experience how to record with in and where is sounds the best.
I am so excited for this semester and I am so shocked that I am learning so damn much within the first week! So, the next few blogs will also revolve around the microphone and how to use it.
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