Frequently Asked Questions

Questions about speech acoustics

• Why do Speech Therapists need to study Acoustics?
• What is a decibel?
• What is a logarithmic scale?
• What is the difference between loudness and intensity?
• Why do we need to multiply by 20 in the decibel scale?
• Why doesn't 0dB mean that nothing is measured?
• Why is log(20) = 1.3?
• How do we convert decibel values on the SPL scale back to pressure?
• How can you calculate the natural frequency of a simple resonator?
• How can you measure the resonant frequency of a simple resonator?
• How are period and frequency inter-related?
• What is the difference between frequency, resonant frequency, natural frequency, and fundamental frequency?
• What is the relationship between period, frequency and wavelength of a periodic sound?
• What is pitch?
• What is timbre?
• How do you find and measure the individual harmonics in a complex periodic waveform?
• Explain harmonic numbering
• What units are used to measure response?
• How can we measure the frequency response of a system
• What is a 'frequency domain' description?
• How do you measure bandwidth from a graph?
• How do you avoid distortion on your recordings?
• How do you measure distortion?
• What is magnetisation?
• What is signal-to-noise ratio?
• How do we measure the frequency response of a microphone?
• What is a filter and what does filtering a signal mean?
• What is a noise signal?
• What is a spectrogram?
• What is the difference between a wide-band and a narrow-band spectrogram?
• What should I look for in a speech spectrogram?
• What is the difference between a harmonic, a sinusoid and a sinewave?
• What is meant by 'phase'?
• How are Pascals converted to dBSPL?
• What is a logarithm?
• What is the difference between loudness and intensity?
• Why do you need harmonics of decreasing size to make a square wave?
• Do you need an infinite number of harmonics to make a complex tone exactly?
• Why does squeezing in more periods in one second mean that the harmonics are further apart?
• Why can an aperiodic sound be considered to have an infinite period?
• How is signals & systems theory applied in speech and hearing science?
• What is meant by a 'frequency domain' explanation?
• What is the relationship between the time & frequency domain pictures for a sinewave through a resonator?
• Explain the frequency response graph for band-pass filters and the use of 'bandwidth'.
• How are band-pass filters used for analysis?
• Isn't the treatment of the filtering of complex sounds as the combination of the filtering of independent sinusoids only true in circumstances when the system is linear?
• How does a system actually change a signal?
• Why can't the ear hear phase?

Questions about speech science

• How does the Laryngograph work?
• What are the characteristics of modal voicing?
• What are the characteristics of breathy voicing?
• What are the characteristics of creaky voice?
• What are the characteristics of falsetto voice?
• What are Lx, Tx, Fx, Dx, Cx, etc?
• What is the best way to measure the "average" fundamental frequency?
• What is the best way to measure the "range" of fundamental frequency?
• What are the sources of variability in vowel production?
• What is "Locus Frequency"?
• In voiceless sounds, what happens to vocal fold vibration?
• Can a speech vibration be random?
• What are the applications of the laryngograph in the clinic?
• What is the relationship between F1 & F2 frequencies and the articulation of vowels?