auditory remnants april 5, 2012 equal loudness curves perceived loudness also depends on frequency
TRANSCRIPT
![Page 1: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/1.jpg)
Auditory Remnants
April 5, 2012
![Page 2: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/2.jpg)
Equal Loudness Curves• Perceived loudness also depends on frequency.
![Page 3: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/3.jpg)
Audiograms• When an audiologist tests your hearing, they determine your hearing threshold at several different frequencies.
• They then chart how much your hearing threshold differs from that of a “normal” listener at those frequencies in an audiogram.
• Noise-induced hearing loss tends to affect higher frequencies first.
• (especially around 4000 Hz)
![Page 4: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/4.jpg)
Age• Sensitivity to higher frequencies also diminishes with age. (“Presbycusis”)
Note: the “teen buzz”
![Page 5: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/5.jpg)
Otitis Media• Kids often get ear infections, which are technically known as otitis media.
• = fluid fills the middle ear
• This leads to a form of conduction deafness, in which sound is not transmitted as well to the cochlea.
• Auditorily, frequencies from 500 to 1000 Hz tend to drop out.
Check out a Praat demo.
![Page 6: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/6.jpg)
Loudness• The perceived loudness of a sound is measured in units called sones.
• The sone scale also exhibits a non-linear relationship with respect to absolute pressure values.
![Page 7: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/7.jpg)
Masking• Another scale for measuring auditory frequency emerged in the 1960s.
• This scale was inspired from the phenomenon of auditory masking.
• One sound can “mask”, or obscure, the perception of another.
• Unmasked:
• Masked:
• Q: How narrow can we make the bandwidth of the noise, before the sinewave becomes perceptible?
• A: Masking bandwidth is narrower at lower frequencies.
![Page 8: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/8.jpg)
Critical Bands• Using this methodology, researchers eventually determined that there were 24 critical bands of hearing.
• The auditory system integrates all acoustic energy within each band.
• Two tones within the same critical band of frequencies sound like one tone
• Ex: critical band #9 ranges from 920-1080 Hz
• F1 and F2 for might merge together
• Each critical band 0.9 mm on the basilar membrane.
• The auditory system consists of 24 band-pass filters.
• Each filter corresponds to one unit on the Bark scale.
![Page 9: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/9.jpg)
Bark Scale of Frequency
• The Bark scale converts acoustic frequencies into numbers for each critical band
![Page 10: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/10.jpg)
Bark TableBand Center Bandwidth Band Center
Bandwidth
1 50 20-100 13 1850 1720-2000
2 150 100-200 14 2150 2000-2320
3 250 200-300 15 2500 2320-2700
4 350 300-400 16 2900 2700-3150
5 450 400-510 17 3400 3150-3700
6 570 510-630 18 4000 3700-4400
7 700 630-770 19 4800 4400-5300
8 840 770-920 20 5800 5300-6400
9 1000 920-1080 21 7000 6400-7700
10 1170 1080-1270 22 8500 7700-9500
11 1370 1270-1480 23 10500 9500-12000
12 1600 1480-1720 24 13500 12000-15500
![Page 11: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/11.jpg)
Spectral Differences
• Acoustic vs. auditory spectra of F1 and F2
![Page 12: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/12.jpg)
Cochleagrams• Cochleagrams are spectrogram-like representations which incorporate auditory transformations for both pitch and loudness perception
• Acoustic spectrogram vs. auditory cochleagram representation of Cantonese word
• Check out Peter’s vowels in Praat.
![Page 13: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/13.jpg)
Hearing Aids et al.• Generally speaking, a hearing aid is simply an amplifier.
• Old style: amplifies all frequencies
• New style: amplifies specific frequencies, based on a listener’s particular hearing capabilities.
• More recently, profoundly deaf listeners may regain some hearing through the use of a cochlear implant (CI).
• For listeners with nerve deafness.
• However, CIs can only transmit a degraded signal to the inner ear.
![Page 14: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/14.jpg)
Cochlear Implants A Cochlear Implant artificially stimulates the nerves which are connected to the cochlea.
![Page 15: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/15.jpg)
Nuts and Bolts• The cochlear implant chain of events:
1. Microphone
2. Speech processor
3. Electrical stimulation
• What the CI user hears is entirely determined by the code in the speech processor
• Number of electrodes stimulating the cochlea ranges between 8 to 22.
• poor frequency resolution
• Also: cochlear implants cannot stimulate the low frequency regions of the auditory nerve
![Page 16: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/16.jpg)
Noise Vocoding• The speech processor operates like a series of critical bands.
• It divides up the frequency scale into 8 (or 22) bands and stimulates each electrode according to the average intensity in each band.
This results in what sounds (to us) like a highly degraded version of natural speech.
![Page 17: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/17.jpg)
What CIs Sound Like• Check out some nursery rhymes which have been processed through a CI simulator:
![Page 18: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/18.jpg)
CI Perception• One thing that is missing from vocoded speech is F0.
• …It only encodes spectral change.
• A former honors student, Aaron Byrnes, put together an experiment testing intonation perception in CI-simulated speech for his honors thesis.
• Tested: discrimination of questions vs. statements
• And identification of most prominent word in a sentence.
• 8 channels:
• 22 channels:
![Page 19: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/19.jpg)
The Findings• CI User:
• Excellent identification of the most prominent word.
• At chance (50%) when distinguishing between statements and questions.
• Normal-hearing listeners (hearing simulated speech):
• Good (90-95%) identification of the prominent word.
• Not too shabby (75%) at distinguishing statements and questions.
• Conclusion 1: F0 information doesn’t get through the CI.
• Conclusion 2: Noise-vocoded speech might not be a completely accurate CI simulation.
![Page 20: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/20.jpg)
Mitigating Factors• The amount of success with Cochlear Implants is highly variable.
• Works best for those who had hearing before they became deaf.
• Depends a lot on the person
• Possibly because of reorganization of the brain
• Works best for (in order):
• Environmental Sounds
• Speech
• Speaking on the telephone (bad)
• Music (really bad)
![Page 21: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/21.jpg)
Critical Period?• For congentially deaf users, the Cochlear Implant provides an unusual test of the “forbidden experiment”.
• The “critical period” is extremely early--
• They perform best, the earlier they receive the implant (12 months old is the lower limit)
• Steady drop-off in performance thereafter
• Difficult to achieve natural levels of fluency in speech.
• Depends on how much they use the implant.
• Partially due to early sensory deprivation.
• Also due to degraded auditory signal.
![Page 22: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/22.jpg)
Practical Considerations• It is largely unknown how well anyone will perform with a cochlear implant before they receive it.
• Possible predictors:
• lipreading ability
• rapid cues for place are largely obscured by the noise vocoding process.
• fMRI scans of brain activity during presentation of auditory stimuli.
![Page 23: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/23.jpg)
One Last Auditory Thought• Frequency coding of sound is found all the way up in the auditory cortex.
• Also: some neurons only fire when sounds change.
![Page 24: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/24.jpg)
Vocal Tract Physiology
April 5, 2012
![Page 25: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/25.jpg)
The Toolkit• There are four primary active articulators in speech.
• (articulators we can move around )
1. The lips
2. The lower jaw (mandible)
3. The tongue
4. The velum
• The pharynx can also be constricted, to some extent.
• Separate sets of muscles control each articulator...
![Page 26: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/26.jpg)
Articulatory Speed• The gold medal goes to the tongue tip...
• which is capable of 7.2 - 9.6 movements per second.
• The rest:
• Mandible 5.9 - 8.4 movements per second
• Back of tongue 5.4 - 8.9
• Velum 5.2 - 7.8
• Lips 5.7 - 7.7
• Note: lips can be raised and lowered faster than they can be protruded and rounded.
![Page 27: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/27.jpg)
1. The Lips• The orbicularis oris muscle surrounds the lips.
• Contraction compresses and rounds the lips.
• A muscle called the mentalis also protrudes the lips.
• Contraction of the risorius muscle retracts the corners of the lips...
• and spreads them.
![Page 28: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/28.jpg)
By the way...• The vowel [i] is typically produced with active lip spreading.
• “Say cheese!”
• What acoustic effect would this have?
• Lips Normal:
• Lips Spread:
• Check ‘em out in Praat.
![Page 29: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/29.jpg)
2. The Jaw• Several different muscles are used to both lower and raise the mandible.
• Primary raisers:
• Masseter
• Temporalis
• Internal pterygoid
![Page 30: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/30.jpg)
2. The Jaw• Several different muscles are used to both lower and raise the mandible.
• Lowerers:
• Anterior belly digastricus
• Geniohyoid
• Mylohyoid
• Note: in lowering, the mandible also retracts.
![Page 31: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/31.jpg)
Articulatory Control• People can produce vowels perfectly fine even when a bite block holds their jaws open. (Lindblom, 1979)
• Adults get the formants right, right from the start...
• But kids need a little time to adjust.
• Abbs et al. (1984) experimented with pulling down people’s jaws...
• when they had to say sequences like [aba] and [afa]!
![Page 32: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/32.jpg)
• Lip muscles adjust immediately for the sudden jaw lowering...
• Adjustment happens faster than electrical signals can travel to the motor cortex and back!
Abbs et al. EMG data
![Page 33: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/33.jpg)
3. The Tongue• The muscles controlling the tongue consist of:
1. Intrinsic muscles
• (completely within the tongue)
2. Extrinsic muscles
• (connect the tongue to outside structures)
• The intrinsic muscles include:
1. The superior longitudinal muscle
2. The inferior longitudinal muscle
3. Transverse muscles
4. Vertical muscles
![Page 34: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/34.jpg)
Tongue: Sagittal View• The superior longitudinal muscle pulls the tongue tip up and back.
• Instrumental in producing alveolars and retroflexes.
• The inferior longitudinal muscle pulls the tongue tip down and back.
• Helps with tongue blade articulations.
![Page 35: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/35.jpg)
Tongue: Coronal View• The transverse muscles pulls in the edges of the tongue, and also lengthens the tongue to some extent.
• Helpful in producing laterals.
• Contraction of the vertical muscles flattens the tongue.
• Interdentals?
![Page 36: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/36.jpg)
Extrinsic #1: Genioglossus• The genioglossus connects the tongue to both the mandible and the hyoid.
• Contraction of the posterior genioglossus moves the whole tongue up and forwards.
• Crucial in palatals.
• Contraction of the anterior genioglossus curls the tongue tip down and back.
![Page 37: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/37.jpg)
Gene-ioglossus
Gene Simmons, of the rock band KISS, is famous for his use of the genioglossus muscle.
![Page 38: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/38.jpg)
Extrinsic #2: Styloglossus• The styloglossus connects the tongue to the “styloid process” in front of the ear.
• Pulls the tongue up and back.
• ...for velar articulations.
• May also help groove (sulcalize) the tongue.
![Page 39: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/39.jpg)
Extrinsic #3: Hyoglossus
• The hyoglossus connects the tongue to the hyoid bone.
• Pulls the tongue down and back.
• = pharyngeals
• Can also pull the sides of the tongue down.
![Page 40: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/40.jpg)
Extrinsic #4: Palatoglossus• The palatoglossus connects the tongue to the soft palate.
• Can be used to raise the back of the tongue.
• And also to lower the velum!
• Lowering the back of the tongue may inadvertently pull the velum down...
• leading to passive nasalization of low vowels.
• Note: Great Lakes vowel shift
![Page 41: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/41.jpg)
Chain Shifting• The Great Lakes Shift is called a chain shift, because first one vowel moves...
• And then a series of others follow.
• In this case, the first shift was:
• Theory: vowels have to stay distinct from one another.
• So listeners can understand what’s being said.
![Page 42: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/42.jpg)
Back to the Shift• The Great Lakes Shift was first noticed in the 1960s.
![Page 43: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/43.jpg)
The Shift, Diagrammed
![Page 44: Auditory Remnants April 5, 2012 Equal Loudness Curves Perceived loudness also depends on frequency](https://reader036.vdocuments.site/reader036/viewer/2022070415/56649f2f5503460f94c493a1/html5/thumbnails/44.jpg)
4. Velar Muscles• The levator palatini raises the velum.
• (connects the velum to the temporal bone)
• The velum is lowered by both the palatoglossus and the palatopharyngeus...
• which connects the palate to the pharynx.