1. what is science? [4 features of the scientific method] empirical: collect and interpret data. deterministic: physical laws apply to principals. not random. generalizations from data to extend on to other situations predictive: learn cause and effect relationships parsimony: describe things in fairly economical terms 2. semitones [how many semitones in one octave, two octaves, how many Hz in an octave, etc.] octave: doubling or halving of a frequency. 1 octave:12 semitones., semitone=1/12 octave - Each semitone is a nonlinear step as you go from low to high- Each step up is bigger than the last one, about 5.9%higher frequency than the one before it. Octave: mathematical relationship btwn freqs; doubling /half of frequency 400= 800 (up) & 200 (down) -12 semitone= 1 octave 3. sampling rate [how does it relate to playback quality, frequencies saved in a recording, Nyquist, aliasing, etc.?] the frequency with which numbers are stored. recordings are a series of discrete snapshots in rapid succession which represents the amplitude at one given moment in time. Hz. Higher sampling rate with more samples will give you a higher fidelity recording. Nyquist: half the sample rate. represents the highest frequency that the recording can accurately reproduce when you play it back. the higher the sample rate the better the quality, stores more digits per second. the lower: fits more minutes. 4. filter types [what do high or low pass or band pass or band reject filters do?] lowpass filter: prevents aliasing, prevents higher frequencies from reaching the digitizing system so they won’t contaminate the lower frequency recordings by being represented as an alias, deletes frequencies above the Nyquist frequency. high: allows high frequencies to pass through, removes or attenuates lower frequencies. band: removes low and high and allows a band in the middle to pass. 5. time vs. frequency domain displays [what’s on the axes, what do the displays show us?] frequency domain: take the time domain wave form and do a Fourier transform to get a spectrum display. time domain: frequency and do a Fourier transform to get a spectrum display. you can see changes in the relative strength of the harmonics. If you raise or lower your pitch you see the harmonics spreading apart or coming back together. noise: all sorts of frequencies present with various different phase relationships to one another that are approx. equal in amplitude. 6. types of spectra: line, FFT, LPC [they reveal different features of speech; what is each one best suited for?] A pure tone has a single vertical line on a spectrum. FFT fast fourier transform: the range of harmonics that are present in a complex sound. useful for revealing features of a sound source but not about the vocal tract filter. LPC: linear predictive coding. shows a spectral envelope. will not show individual harmonics or details of a sound source but will reveal what the vocal tract filter is doing, how the vocal tract shapes the sound given to it by the larynx. 7. 3D spectrogram features [what are the three dimensions?] Spectrogram: way to represent sound graphically. time-left to right on the x-axis. frequency going up on the y axis. the darkness of the trace is reflective of the sound at any given frequency and at any time on the display. 8. vocal modulation vs. perturbation [acoustic definitions; what does each one sound like alone or in combination?] Perturbation involves the minor imperfections found within the vocal signal. Although normal voices have minimal perturbation voices that lack smoothness sounding hoarse or rough will have high values of perturbation. - Perturbation of jitter and shine that we considered a while ago occurs very rapidly from one glottal cycle to the next. - Perturbation cannot be measured only heard if a problem exists. Modulation involves a tremor, unsteadiness in the voice. There will be rhythmic changes that are fairly predictable in the fundamental frequency and in the amplitude of the voice. Modulation is measured w/ rate, how extreme, and how steady the voice is. - gradual increases and decreases that occur over the course of many individual glottal cycles. - Is rhythmic. A voice with high perturbation would also have issues with jitter (frequency perturbation) and shimmer (amplitude perturbation) and would sound rough and hoarse. The voice of a person who had modulation would sound wobbly. -can have both perturbation AND modulation. Perturbation- hoarseness/rough, random and rapid change in either period/amplitude from cycle -tocycle.jitter (Freq/DURATION Perturbation) and shimmer (AMPLITUDE Perturbation) co-occur Modulation sounds shaky - but more rythmic, slower, gradual, pattern: (FM/AM co-occur)FM=Freq modulation, AM = Amplitude modulation BOTH FM/AM CO-OCCUR Combined perturbation & modulation= Hoarse Voice & Shaky/Tremulous 9. direct measures vs. estimates of subglottal pressure [how can we get definite measures vs. how can we get a reasonable estimate? what happens if we change subglottal pressure?] Subglottal pressure is key contributor in adjusting loudness (vocal intensity). Respiratory system Direct SubGlottal Pressure Measure (PS or PSUB) 1.Tracheal Puncture: Dr. punctures trachea, inserts mini transducer that directly measures pressure; invasive 2. Esophageal Pressure (Balloon): Used much more in past; Transducer in balloon, swallow part way into esophagus & sensor measures pressure on shared wall btwn trach/esophagus. 3. Estimating SubGlottal Pressure: Indirect Estimate of Intra-Oral Pressure (io): -measure pressure at specific point/time where io pressure= subglottal pressure (measured directly below larynx). briefly occurs during production of /p/ & vowel (bilabial plosive) 4. Oral estimating of subglottal pressure from oral pressure measurement correspond very closely w pressure directly measured from trachea. 5. Oral air flow - when vowels more airflow and when consonant constriction the airflow will cease. 6. Wide band airflow signal very sensitive to rapid changes in airflow as vf open and close. 10.calculate average air flow [dividing volume used by time] Volume of air that flows in given time. (Volume divided by time). average flow= 1 liter of air and phonation lasts for 5 seconds = 1/5 liter per second or 200 cc/second or 0.2 liters/second If phonate for 15 seconds and use 5 liters of air, then each liter has lasted 3(=15/5) seconds. So flow rate would be 1/3 of liter/sec