The most common microphone, electrets vary in quality. Learn their origin, their design, their benefits, and in particular their application for musicians who produce Youtubes or have a home production studio.

1. No longer second rate
ELECTRET MICROPHONES AND
HOME MUSIC PRODUCTION
CLARICE STASZ, 2013

2. 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.

3. 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.

4. 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

5. Invented 1962
 Gerhard Sessler and James West at Bell Labs
Developed to improved telephone communications.

6. 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

7. Or,
 A microphone consisting of an electret
transducer in which the foil electret
diaphragm 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.

8. Engineering
Preamp
Vibrating membrane
Itc.nyu.edu

9. Small size advantage
Openmusiclabs.com

10. You use them all the time.

11. 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.

12. 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.

13. 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

14. 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.

15. A look inside one type
 Being condensors, they need power so some
include an amp.
http://sound.westhost.com/project93.htm

16. Others include a battery and
then connect to the amp.
www.caitches.com

17. 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

18. 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

19. Home recording
Today you can find
good quality electrets
for under $50, with the
specs you need in
terms of pickup
pattern, frequency
Stereo ominidirectional
with direct plugin to response, and more.
minimize vibration

20. Performing mics as well.
This looks like a dynamic
mic.
It’s an electret
specifically for
performing vocalists to
reduce pops, optimize
lower frequency
response, and minimize
distortion. It is also a
cardioid design.

21. 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 electret
and an externally polarized condensor mic in
performance - that gap is narrowing.”
 From “Dale” on Gearslutz.com.

22. 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.

23. 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.

24. Connecting to computer
 This is a topic in itself. Try these for help:
 http://manual.audacityteam.org/man/Tutoria
l_-_Connecting_a_Microphone
 http://www.ehow.com/how_6362940_connec
t-electric-condenser-microphone-pc.html
 http://support.apple.com/kb/HT2508

25. 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.

26. 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.

27. If you evaluate this….
Don’t hesitate to note
errors,
Or to suggest additions.
ukestasz@gmail.com