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Sound Audiology. Perry C. Hanavan, Au.D. Audiologist. Sound. Vibration Perception. Propagation of Sound. Condensations ____________ Example of molecular motion Components of sinusoid Transverse wave simulation Applet: Square, triangle, simulation. Components of Sound.

Transcripts

Sound Audiology Perry C. Hanavan, Au.D. Audiologist

Sound Vibration Perception

Propagation of Sound Condensations ____________ Example of atomic movement Components of sinusoid Transverse wave reproduction Applet: Square, triangle, reenactment

Components of Sound Physical Psychological - - - Intensity Loudness Frequency ________ Duration Length

Intensity Decibel Unit of measure of power dB = 10logR (R=ratio)

Problem Human listening to force dynamic range is very expansive 1 Softest sound 1,000,000,000,000 Loudest sound

Intensity Dynamic Range 1 10 100 1000 10000 100000 1000000 10000000 100000000 1000000000 10000000000 100000000000 1000000000000 10000000000000 100000000000000

Honey I Shrunk the Kids 1,3,5 or 1, 4, 8, 12 and so on diminishes dynamic range to some degree 1, 10, 100, 1000 psychologists more Yet, element range is very extensive

Solution Ratio Compare power esteem (number) to reference 8:4 (truly 2:1)

Aha! Proportion Compare 2 Numbers 1/1 =1 10/1 =10 100/1 =100 1000/1 =1000 10000/1 100000/1 1000000/1 10000000/1 100000000/1 1000000000/1 10000000000/1 100000000000/1 1000000000000/1 10000000000000/1 100000000000000/1

Logarithms!! Since a proportion has been changed over Next stride: Convert proportions to logs (base 10)

Lets Work with Logs!!! 1 = 0 10 = 1 100 = 2 100000000000000 = ? 14 .1 = - 1 .01 = - 2 .00000000001 = ? - 11

So is that a decibel? So far we have 1. Changed over a proportion to a number (10:1=10) 2. Changed over the proportion to a log (10=1) We have made a ____ (A.G. Ringer) There are 10 decibels in a bel 2 bels = 20 decibels 8 bels = 80 decibels

WOW!!! Decibel = 10 log _____ A decibel comprises of: 1. Proportion 2. Log 3. X10

That was simple, how about we hone: Integer: 10 X 10 = 100 Log: 1 + 1 = 2 Integer: 1000 X 1000 = ? Log: 3 + 3 = 6 Now take the log times 10 to change over to decibels

Not terrible, how about we attempt this: Integer: 100/10 = 10 Log: 2 - 1 = 1 Integer: 1000000/100 = ? Log: 6 – 2 = 4 Now take the log times 10 to change over to decibels

Ok, I can do that, yet… Some numbers are very simple to work with in logs However, a few numbers you have to utilize an adding machine or look in a CRC book of tables Or you can retain a few numbers and figure heaps of logs Hint: log = bel

Oh, one additionally thing: Measures of ________ are regularly made in Sound Pressure Level (SPL) as opposed to Intensity Level (IL) IL: measure of vitality streaming through a 1cm 2 surface region SPL: measure of weight applied on a 1cm 2 surface region IL = SPL 2 dB IL =10logR parallels dB SPL =20logR

dB Intensity Level Measure of vitality Reference 1.0 X 10 - 16 watts/cm 2 or .0000000000000001 watts/cm 2

dB Sound Pressure Level Measure of drive or weight Reference 20 microPA

Sound Pressure Level 20/20 = 1:1 40/20 = 2:1 60/20 = 3:1 200/20 = 10:1 Intensity Level 1.0x10 - 16/1.0x10 - 16 2.0x10 - 16/1.0x10 - 16 3.0x10 - 16/1.0x10 - 16 4.0x10 - 16/1.0x10 - 16 1.0x10 - 15/1.0x10 - 16 Ratios in IL and SPL

dB IL =10logR or dB SPL =20logR Ratio No. Log dB IL dB SPL 1:1 1 0 0 0 2:1 2 .3010 3.0 6.0 3:1 3 .4771 4.8 9.6 4:1 4 .6020 6.0 12.0 5:1 5 .6990 7.0 14.0 6:1 6 .7781 7.8 15.6 7:1 7 .8451 8.5 17.0 8:1 8 .9030 9.0 18.0 9:1 9 .9542 9.5 19.0 10:1 10 1.000 10.0 20.0

Can you do this? Twofold SPL? Twofold IL? Triple SPL Triple IL? Fourfold SPL? Fourfold IL?

What about this? Split IL? Divide SPL?

Practical Applications of dB If a tyke\'s ear channel is ___ times as little as a grown-up, what happens to the SPL in the tyke\'s ear waterway? In the event that an understudy is 3 times nearer to the instructor\'s voice than another, what amount more SPL achieves the kid sitting close to the educator?

Hearing Level Converting SPL to HL (HTL)