latest Version (2024/2025)
4 features of the scientific method - ✔✔1) Science is empirical- we collect data and interpret
it (based on data)
2) Science is Deterministic - Things are not random. Because of cause and effect, we can
draw generalizations from the data that we have and extrapolate
3) Science is predictive - if you do this, then that will happen.
4) Science is parsimonious - use the simplest explanation possible, try to describe things in
economical terms so we can understand it. Use the simplest terms possible, but no simpler.
Why do SLPs use technology - ✔✔1) Overcome listener bias - computer isn't influenced by
what it has heard before. It is a consistent, reliable measure.
2) Describe severity objectively - standardizes measures of speech
3) Track progress over time - helps demonstrate treatment efficacy
4) Helps to comply with ASHA's focus on EBP - provides hard data to measure rather than
just gut feelings about progress based on experience.
5) Biofeedback- computer display in real time - ex: visipitch shows intonations on screen in
real time, shows them progress as they speak, better than playing back a recording.
How can acoustics help? - ✔✔acoustics can tell us a lot about what is going on that can't be
seen. Acoustics is a way of using quantitative measures to to describe a physical
phenomenon, rather than relying on our human impressions
Frequency - ✔✔how frequently a waveform repeats. Measured in Hz (cycles per second).
Within the same window length, a higher frequency sound wave will show more repetitions
than a lower frequency sound wave
simplest sound - ✔✔pure tone (sine wave)
Pitch - ✔✔the subjective measure of frequency; you cannot measure pitch with an
instrument. You can have people match pitch perception to frequencies.
, Intensity - ✔✔amplitude or size of a sound.Adjusting volume, is adjusting the physical
intensity of sound.
Why use a logarithmic scale for intensity? - ✔✔This is necessary because the highest
amplitude sound we can perceive is 1 trillion times the softest sound we can perceive (120
dB).
Loudness - ✔✔Perceptual characteristic of sound. Listener can judge loudness, there is no
equipment that can measure loudness. Human reaction to the amplitude of a sound. Can be
measured with a psycho-physical scale.
Greatest sensitivity to loudness is between - ✔✔1,000 - 5,000 Hz, threshold is much higher
at very low or very high frequencies
Why do audiometers use HL and not SPL? - ✔✔to compensate for known differences in
human hearing sensitivity.
Equal loudness contours - ✔✔Created by presenting a known frequency (1,000 Hz) and then
other tones are played and the listener has to adjust the loudness until it sounds the same
as the 1,000 Hz tone
In order to perceive low amplitude sounds at low frequency as the same loudness as higher
frequency sounds.... - ✔✔have to be adjusted up a lot for them to be perceived as the same
loudness as the original sound
at high intensity, - ✔✔the sounds seem to be equal in loudness to intensity.
general rule is that a 6-10 dB increase - ✔✔is generally perceived as double as loud
Frequency Difference limen - ✔✔smallest change in frequency that is detectable by a
listener. As frequency increases, the DL becomes much greater