Physics 1240 Thurs 2/23/06Today: Loudness versus pitchNext time: frequencies of musical notes, piano keyboardOutline- Physical versus psychological- Loudness scaling- Loudness versus pitch- Sones versus phones- More on the audible range and hearing lossstimuli sensationfrequency pitchintensity loudnesswaveform timbre(fast oscillations)envelope(slow variation)Loudness ScalingRoughly, a doubling of loudness corresponds to a 6-10 dB increase in sound intensity10 phonsis the loudness of a 10 dB 1000 Hz pure toneDemo: IPO Track 17,18 - loudness scalingYou cannot argue physics with a complete stranger! So ...Introduce yourself to the person near you (help people sitting alone). "Hi, I'm Alia." "Nice to meet you Peter." Etc. Find out where they were born.CT12.1The person I just met was born inA) The contiguous United States, west of the Mississippi RiverB) The contiguous United States, east of the Mississippi RiverC) Alaska or HawaiiD) Outside of the United StatesCT12.2Loudness is a physical quantity and measured using the SIL (dB scale).A) trueB) falseCT12.3What is the loudness of 80 dB 1000 Hz tone?A) 1000 phonsB) 100 phonsC) 80 phonsD) 90 sonesE) none of the aboveCT12.4What is the loudness of 80 dB 7000 Hz tone?A) 1000 phonsB) 100 phonsC) 80 phonsD) 90 sonesE) unable to determine with the information given in class todayCT12.5Why can't we determine the answer to the previous Concept Test?A) a sone is 2 x π x 40 phonsB) loudness is a sensationC) loudness depends both on frequency and intensityD) none of the aboveFletcher-Munson diagramLoudness as a function of SIL and frequency Loudness ( frequency, SIL )Phons ( dB, Hz )Topographic map -- Altitude( x, y )weather map -- pressure( x, y )so-called "two-dimensional contour plot"Fletcher-Munson diagramLoudness ( f, SIL ) --- Phons ( dB, Hz )CT12.6 The volume of an amplifier is increased so that a quiet sound increases by a factor of 10,000 in intensity (measured in units Wm2). How much does the SIL go up?A) 1000 dBB) 100 dBC) 40 dBD) 10 dBE) none of the aboveCT12.7 For the sound above, how will the quality of the sound change?A) the overall quality of the sound will not changeB) it will be much quieterC) it will become more brassy or shrillD) the bass frequency range will sound too loudCT12.8 If you hear two pure tones with f=200 Hz and f=10,000 Hz, both at 60 dB SIL, which will be the loudest? (You must use the Fletcher-Munson diagram to get this problem right.)A) 200 Hz toneB) 10,000 Hz toneC) neitherDon’t need to know about sonessones (newer unit) versus phons (older unit)(analogous to meters versus yards)1 sone = the loudness of a 40dB 1000 Hz pure tone2 sones is twice as loud as 1 soneNo simple relationship between sones and phonesCT12.9 Don’t need to know about sonesA 1000 Hz, 40 dB sound is increased in intensity until it is twice as loud. How loud is it?A) 2 sonesB) 80 phonsC) 80 dBD) unable to determine based on what we have learned todayCT12.10 Don’t need to know about sonesA 1000 Hz, 60 dB sound is increased 10 dB. How loud is it?A) 3 sonesB) 70 phonsC) 70 dBD) none of the aboveWe loose ability to hear high frequencies with ageHearing loss at different ages men - solid linewomen - dashed
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