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Decibel Unit Notes
Notes over Decibels including some examples
Course
Introduction to Audiology (CDO 331)
19 Documents
Students shared 19 documents in this course
University
Central Michigan University
Academic year: 2022/2023
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Central Michigan University
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The Decibel
Decibel
- Unit of measurement to describe a magnitude of a sound Log 10 1000=x Y=Log 10 X 10^x =1000 10^y=X X=
Sound intensity and sound pressure
- Sound pressure indicates hoe compressed or rarefied the particles are
- Sound intensity how much sound power is transferred from the sound to the surrounding area
- A powerful sound source will produce a powerful sound pressure
- Two ways to describe/represent strength of sound
- I is proportional to p^
- Decibel is a logarithmic unit that indicates the relative difference between two measurements
Absolute versus relative difference
- Ex: Backpack with laptop in it add 2 heavy textbooks o 10 pounds heavier; absolute twice as heavyLrelatice
The Bel developed to describe the amount of power that was lost along cables for speech signals.
- L=log10 (p2/p1) [B]
- 01,000,000W
- 1x10^-12W 1x10^6W
- Log(1x10^-12)= -12 Log(1x10^6)=
Different types of decibels it does not measure a physical property
- Sound intensity level (dBIL)
- Sound pressure level (dBSPL)
Reference point
- The sound pressure 20mPa (pascals)
- Sound intensity 10^-12 W/m^
When the sound pressure doubles, the sound pressure level increases by 6dB
When the sound pressure increases by x10 the dBSPL increases by 20 dB
Sound Pressure (dBSPL) Sound Intensity (dBIL) Doubling +6dB +3dB Tenfold +20dB +10dB
Types of dB
- dBSPL: the objective measurement of sound
- dBHL: make 0dB=average human threshold, the method is to subtract the dBSPL AHT from value
- dBSL: for patients with loss present at constant level above threshold, the method is to subtract value from patient’s threshold
Computing dBHL +dBSPL +dbSL
- dBHL=dBSPL-Reference value
- dBSL=dBHL of stimulus-dBHL of patient threshold
Need conversions depending on what you are testing
- hearing aid output
- noise level measurements
- hearing loss patient to normal hearing
- speech material test
- screening tests for CAPD
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Decibel Unit Notes
Course: Introduction to Audiology (CDO 331)
19 Documents
Students shared 19 documents in this course
University: Central Michigan University
Was this document helpful?
The Decibel
Decibel
- Unit of measurement to describe a magnitude of a sound
Log10 1000=x Y=Log10X
10^x =1000 10^y=X
X=3
Sound intensity and sound pressure
- Sound pressure indicates hoe compressed or rarefied the particles are
- Sound intensity how much sound power is transferred from the sound to the surrounding area
- A powerful sound source will produce a powerful sound pressure
- Two ways to describe/represent strength of sound
- I is proportional to p^2
- Decibel is a logarithmic unit that indicates the relative difference between two measurements
Absolute versus relative difference
- Ex: Backpack with laptop in it add 2 heavy textbooks
o10 pounds heavier; absolute twice as heavyLrelatice
The Bel developed to describe the amount of power that was lost along cables for speech signals.
- L=log10 (p2/p1) [B]
- 0.000000000001W1,000,000W
- 1x10^-12W 1x10^6W
- Log(1x10^-12)= -12 Log(1x10^6)=6
Different types of decibels it does not measure a physical property
- Sound intensity level (dBIL)
- Sound pressure level (dBSPL)
Reference point
- The sound pressure 20mPa (pascals)
- Sound intensity 10^-12 W/m^2
When the sound pressure doubles, the sound pressure level increases by 6dB
When the sound pressure increases by x10 the dBSPL increases by 20 dB
Sound Pressure (dBSPL) Sound Intensity (dBIL)
Doubling +6dB +3dB
Tenfold +20dB +10dB
