This document provides biographical information about Rebecca Reich, including her education and work experience related to acoustics and audio engineering. It notes that she has a B.Eng in electrical engineering with a minor in arts, and earned an S.M. in Media Arts and Sciences. Her work has involved programming, customer technical support, and managing support teams in various locations. The document also discusses her interest in flexible work opportunities through programs like Mitacs in Canada.

1. Rebecca Reich
May 24 2011

2.  Who am I?
h
 Audio / Acoustics around the clock
d d h l k

4. 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
 B. Eng, electrical, Minor Arts
 NRC Women in Engineering and Science scholarship
g g p
• classroom and concert hall acoustics
 S.M., Media Arts and Sciences
 Cochlear implants
hl l
 how do they sound when music plays through them?

5. 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
 Programming 1’s and 0’s
 Programming user software
 Customer technical
support

6. 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
 One year in Copenhagen, DK
 Customer technical support

7. 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
 Customer technical support (five months)
C h i l (fi h )
 Manager, customer technical support team
 China, Japan, Canada

9. 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
• Flexible
• People job
www.mitacs.ca
• Learn new stuff!

10. •$7 500 industry
75 y
$15 000 •$7 500 Mitacs/FQRNT
$10 000 $5000
min for student flexible
•$36 000 industry
$80 000 •$44 000 Mitacs/FQRNT
$10 000 $10 000 $10 000
$20 000
$10 000 $10 000 $10 000 flexible
internships

11. Let’s get started…
Let’s get started

12.  Sound is a form of energy (like electricity or
f f
light)
 Sound is made when air molecules vibrate
d d h l l b
and move in a pattern waves
Animation courtesy of Dr. Dan Russell, Kettering University

13. Particle motion is a function of space
(displacement, amplitude)
and time

14. Longitudinal wave:
particle motion is parallel to motion of disturbance
created by moving object
 Wave causes areas of compression (high
pressure) and rarefaction (low pressure). We
) d f i (l ) W
call this PRESSURE waves

15. c = 343m/s (air, 20oC)
we INTERPRET sound waves

16. Frequency:
F
how often the particles are moving back and forth:
# of complete back‐and‐forth vibrations
p
of a particle of the medium Hertz:
per unit of time # cycles per second
20Hz – 20 000Hz
H H
Sensation of frequency = pitch

18.  Greater amplitude of disturbance causes
G li d f di b
greater displacement (amplitude) of particles
 More amplitude  more energy
 Intensity = power/area (Watts/m2)
 Move away from sound ,intensity decreases
(inverse square)
 Humans can detect as low as 1*10‐12 W/m2, ,
and as high as 1 billion times this!
 Due to large range: dB
 1*10‐12 W/m2 = 0 dB
d

20. sleep
work
work
wake
play

21.  Your alarm‐clock radio: fast facts
f f
06:00
 Why does Boston Acoustics sound better
than Accurian?

23. Looking at an average over a window of time…

24. Why does everyone sound good singing in the
Wh d d d i i i th
shower?
06:15
5
 ACOUSTICS: study of waves in a medium
 Direct, Reflected, Refracted, Absorbed
fl d f d b b d

25.  Hard surfaces
f
 little sound absorbed (ceramic tile)
 many reflections reverberation
~50ms is threshold for
i th h ld f
hearing echo

26.  Small space
 accumulation of reflections
increases volume
 you sound more powerful!
 Resonant cavity
 Shower stall dimensions
cause standing waves at
d
low frequencies; vocals in
this range will be boosted

28.  Car stereo acoustics
08:00
 “dead” sound environment, depends on materials
(leather vs. upholstry)
 transitory (windows open vs. closed)
 loud: riding the volume knob

29.  Single‐band compressor, loud bass information
l b d l db f
modulates gain of the entire audio signal 
suboptimal maximum perceived loudness & gain
pumping

30.  Listening to iPod
 [Portnuff] listening to earbuds for 90 minutes/day at
80% volume is probably safe for long‐term hearing
(softer is better: you can safely tune in at 70%
volume for about 4½ hours a day.)
volume for about 4½ hours a day )
~ one in five teenagers had some kind of hearing loss in
2005 2006, up from 15% of teenagers in the late 1980s and
2005‐2006, up from 15% of teenagers in the late 1980s and
early 90s, according to a study of nearly 5,000 people age
12 to 19 published in the Journal of the American Medical
Association.

31.  The maximum exposure time for unprotected
Th i ti f t t d
ears per day at 90 dB is 8 hours.
 For every 5 dB increase in volume the maximum
For every 5 dB increase in volume, the maximum
exposure time is cut in half.
 95
95 dB = 4 hours
4
 100 dB = 2 hours
 110 dB = 30 minutes
 120 dB = 7.5 minutes
 Apple set 100dB limit in Europe, still 115dB in
USA

32.  Dynamic compression a reality of modern
f
music recordings (louder is better)
 Causes listener fatigue
l f

34. 08:45
45
 In general, noise levels above 45‐50 dB(A) tend to be
I l i l l b dB(A) d b
disturbing
 Speech Intelligibility Index (SII): how well speech can be
understood in the presence of noise.
p
 range: 0 (perfect privacy) to (perfect intelligibility)
 Theatres and auditoriums need high SII values, but offices
and other private locations need low SII
 SII <= 0.2 gives employees speech privacy and blocks most
SII <= 0 2 gives employees speech privacy and blocks most
acoustical distractions

35.  Ceiling and floor
C ili d fl
 Partitions (partial‐height screens)
 Workstation and Occupant Orientation
 Lighting fixtures (flat vs grill)
 Noise Masking System

36.  Noise‐cancellation headphones
N i ll ti h d h
 Active vs. Passive
09:00
9  Active:
▪ produce “anti‐noise”
▪ require battery
▪ cancel low‐frequency continuous
cancel low frequency, continuous
sound actively, high‐frequency through
design
 Passive
▪ physical block; works over wide range
▪ no battery
▪ weaker bass response (due to speaker
size)

37.  Your hearing… getting old…”eh?”
18:00
• outer/middle ear
conductive
• often reversible
• inner ear
sensorineural • not reversible
• can be age‐related
b l t d

38.  Symptoms
 Certain sounds seem overly loud
 Difficulty hearing things in noisy areas
 High‐pitched sounds such as "s" or
"th" are hard to distinguish from one
another
 Men's voices are easier to hear than
womens.
 Other people's voices sound mumbled
p p 20% over 65
or slurred
 Ringing in the ears 40% over 75
 “I hear but I can’t understand”
80% nursing home
residents

39.  Not just amplifiers
f
 ex. frequency translation
 Adapt to environment
 cocktail party effect
 Connected
 bluetooth
 bilateral communication

40.  36,000 people world‐
36 000 people world
wide received cochlear
implants over the last
two decades.
t d d
 FDA‐approved 1985
(adults), 1990 (children)
 Ad lt
Adults can now be
b
considered candidates if
they have severe‐to‐
profound hearing loss
f d h i l
and understand less
than 50% of sentences
spoken to them
k t th
violin violin, processed

41. noises off!
ff
22:00