Electret microphones and home music production
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Transcript of Electret microphones and home music production
ELECTRET MICROPHONES AND HOME MUSIC PRODUCTION
CLARICE STASZ, 2013
No longer second rate
Why this Slideshow?
This is a project for Music Production, a Coursera class taught by Loudon Stearns of Berklee School of Music.
I was going to do a presentation on dynamic versus condensor microphones, when I came across the word “electret.”
It was not covered in class, so I explored just what they were, and their applications for musicians.
CAVEAT…
Because this was designed for those in the course, it assumes some basic familiarity with microphones and terms commonly used in music production.
These include cardioid, frequency response, transducer, dynamic microphone, and such.
Electrets are based on Condenser Microphones, which
Are less sturdy than dynamic mics (so don’t swing them around the stage)
Are the preferred studio mic for reproduction value
Offer larger frequency response for collecting partials than dynamic mics
Require phantom power turned on
Invented 1962
Gerhard Sessler and James West at Bell Labs
Developed to improved telephone communications.
DEFINITION
“An electret microphone is a type of condenser microphone, which eliminates the need for a polarizing power supply by using a permanently charged material.”
http://en.wikipedia.org/wiki/Electret_microphone
Or, A microphone consisting of an electret
transducer in which the foil electretdiaphragm is placed next to a perforated, ridged, metal or metal-coated backplate, and output voltage, taken between diaphragm and backplate, is proportional to the displacement of the diaphragm.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
Engineering
Vibrating membrane
Preamp
Itc.nyu.edu
Small size advantage
Openmusiclabs.com
You use them all the time.
Do you make Youtubes?
Electrets are in your laptop and portable phone.
They consist of about 9o% of microphones in use today.
Their quality is surprisingly good for many purposes.
Time for a new recording mic?
Your computer mic is fine for everyday uses, like Skype, or taking audio notes.
Music on the same mic may sound tinny because of distortion and limited response. You sound better than what you hear.
Benefits of electret
Very inexpensive, under $1 for lowest quality, hence popular with gearheads
Suit voice recording well as for interviews
Extremely wide frequency response (from 10Hz to 30kHz ) in best cases.
Sample inexpensive electret
Technically superior
This is according to the technical sound engineer papers . The electret design is supposed to be the most accurate transducer.
Of course, this will be affected by the quality of the production. Nonetheless, theoretically, electrets should be the best form of microphone.
A look inside one type
Being condensors, they need power so some include an amp.
http://sound.westhost.com/project93.htm
Others include a battery and then connect to the amp.
www.caitches.com
Electrets have a bad reputation with some
Vibrating membrane can wear out in a couple of years
More fragile overall than a dynamic mic
Cheap models mean poor quality
Some users find the bass range unsatisfactory
Disadvantages of lower quality (cheap) models
Output impedance is relatively high
Relatively low sensitivity
Noise is relatively high
Sound level handling ability is low,
typically < 90 dBSPL
Home recording
Today you can find good quality electrets for under $50, with the specs you need in terms of pickup pattern, frequency response, and more. Stereo ominidirectional
with direct plugin to minimize vibration
Performing mics as well.
This looks like a dynamic mic.
It’s an electretspecifically for performing vocalists to reduce pops, optimize lower frequency response, and minimize distortion. It is also a cardioid design.
One pro’s experience
“The cheap electret mics polarize the diaphragm. This is cheap to make but results in a diaphragm that's quite thick (maybe 20 microns or so).
A back-electret puts that charge on a sheet that's between the backplate and the diaphragm. With this arrangement, you can use a normal diaphragm thickness… so it may be difficult to tell the difference between an electretand an externally polarized condensor mic in performance - that gap is narrowing.”
From “Dale” on Gearslutz.com.
Recommendations
For spoken word or singing with a single instrument, your computer mic could be just fine
For higher quality, and better mixes, explore quality electrets now widely available at moderate prices.
For performing, because electrets are technically the purest transducer, you may want to try one out.
In other words…
Where ten years ago people said the electrets were lousy for serious sound work, this is no longer true.
Major microphone firms make professional level electrets, up into hundreds of dollars.
Given the same price and specs, the back-electret design is your better choice.
Connecting to computer
This is a topic in itself. Try these for help:
http://manual.audacityteam.org/man/Tutorial_-_Connecting_a_Microphone
http://www.ehow.com/how_6362940_connect-electric-condenser-microphone-pc.html
http://support.apple.com/kb/HT2508
Self-evaluation
As a result of this project, I learned:
Three of my music-based mics are electrets: flute, ukulele, and Sony mini-stereo recording.
It is worth using an external electret for my laptop for quality recording.
A lot of sound reference materials require some engineering background to comprehend. I definitely missed some understanding in putting this together.
If I had more time,
I’d have sound samples with various mics to demonstrate differences
I’d use Camtasia to make a video from this PowerPoint with an audio track added
In that last case, I’d reduce all the written slides and have more visuals. For example, I’d open up a mic to show the parts.