Sound 101 Cheat Sheet*
Sound: compression and rarefaction within a medium (which in singing = air) Compression: things are closer together Rarefaction: things are farther apart Period: one cycle of compression and rarefaction “the propagation of pressure waves radiating from a vibrating body through an elastic medium”
Four measurable, inter-related properties:
1. Frequency 4:25 - number of periods that occur each second - produced by an oscillating or vibrating body (ie the sound source or vibrator) - measured in cycles per second, or hertz (Hz) - eg: 440 Hz = each second, 440 cycles of compression and rarefaction occur within a medium (ie air) - musical sounds are made up of many frequencies combined to create a complex sound wave - for the purposes of keeping the Sound Cheat Sheet as EASY TO FOLLOW AS HUMANLY POSSIBLE, the frequencies above the Fundamental Frequency (see below) are referred to as “harmonics” or “upper frequencies” (but not “overtones”)
1a) Fundamental Frequency 6:10 & 10:17 - lowest frequency / harmonic of a sound
- abbreviated to “H1” (ie first / lowest harmonic) and/or “Fo” (ie “frequency of oscillation” where “oscillation” refers to “periods”) - basically equivalent to perceived pitch of sound and may be referred to as an objective measurement of pitch - eg: 440 Hz = A440 / A4 / A above middle C 11:20 - faster / higher Fundamental Frequency = higher pitch and slower / lower Fundamental Frequency = lower pitch - eg 1: a small increase or decrease of the Fundamental Frequency will most likely be perceived as a “sharp” or “flat” sound - eg 2: “Baroque tuning” is lowered approximately a half-step (or semi-tone) from generally accepted contemporary tuning, so in Baroque tuning, A4 is NOT A440 (ie does not have a Fundamental Frequency of 440 Hz) but A415 (ie has a Fundamental Frequency of 415 Hz) - eg 3: doubling or halving the Fundamental Frequency of a sound results in an octave change, so A440 / 440 Hz = A4 and A880 / 880 Hz = A5 and A220 / 220 Hz = A3 1b) Harmonics 6:48 - frequencies that make up a sound - either the Fundamental Frequency OR whole number multiples of the Fundamental Frequency (note: frequencies that are not whole number multiples of the Fundamental Frequency are perceived as noise) - abbreviated to “H#” (ie the first harmonic (ie the Fundamental Frequency) = H1, the second harmonic = H2, etc.)
1bi) Harmonic Series 17:05 - the relationship between the Fundamental Frequency and its harmonics
- harmonics occur in a consistent pattern: Fo/H1 to H2 = 8ve, H2 to H3 = p5th, H3 to H4 = p4th, H4 to H5 = M3rd, etc. - usually, the Fundamental Frequency is the strongest (ie loudest) frequency/harmonic in a sound (fun fact: overtone singing occurs when one (or more!) harmonics is nearly as loud or louder than the Fundamental Frequency so it ‘sticks out’ of the sound)
2. Amplitude 19:15 - refers to the relative magnitude (or amplitude) of the displacement of molecules during a period (or cycle of compression and rarefaction) - generally referred to as produced by/at the sound source / vibrator - thicker / bigger sound source / vibrator = greater displacement of molecules during compression and rarefaction cycles = louder perceived sound - eg: the piano strings that produce the lowest pitches (AKA slowest Fundamental Frequencies) are thicker than the strings that produce the highest pitches (AKA fastest Fundamental Frequencies) so when the thicker strings vibrate, the magnitude of their movement is greater than the magnitude of the movement of the thinner strings, so they may sound louder (AND they have a ‘richer’ tone quality … which has to do with Fundamental Frequency AND timbre so READ ON!) - may be referred to as the objective measurement of loudness - calculated on a logarithmic scale (ie non-linear scale, similar to the scale that is used to measure the strength of an earthquake) - measured in decibels (dB) using a decibel or sound level meter
2a) Intensity 21:03 - refers to relationship between amount of harmonics in sound and amplitude (or strength) of upper harmonics in sound - more overall harmonics in the sound AND strong higher harmonics = more intense sound = louder perceived sound - fewer overall harmonics in the sound AND weaker higher harmonics = less intense sound = softer perceived sound - may be viewed and measured using sound analysis programmes - at the simplest level, may be thought of as a product of the shape of the resonator - sound source resonator shaped in such a way as to strengthen upper harmonics
3. Timbre 21:20 - AKA tone quality - result of unique patterns of strengthened and weakened harmonics in each sound - resonator / filter is responsible for selectively strengthening or weakening harmonics - similarly-shaped resonators will strengthen and/or weaken many of the same harmonics in a sound - eg 1: all brass instruments have a similarly-shaped resonator (the HORN part of the instrument) so they will strengthen and/or weaken similar harmonics so they will have a similar sound that is easily distinguishable from other instrument families, such as wood winds - eg 2: family members who have similarly-shaped necks and faces, will likely be difficult to tell apart when talking to them on the phone because those similarly-shaped resonators are strengthening and weakening nearly the same harmonics - measured using sound analysis programmes
3a) Tone Colour 25:17 - when the vibrator / sound source creates a low pitch (AKA slow Fundamental Frequency), the resonator / filter gets MORE harmonics to choose from to produce the final sound and when the vibrator / sound source creates a high pitch (AKA fast Fundamental Frequency), the resonator / filter gets FEWER harmonics to choose from to produce the final sound … MORE harmonics = darker sound and FEWER harmonics = brighter sound - eg 1 (role of the vibrator / sound source): a tuba and a trumpet are both brass instruments so they have similarly-shaped resonators (and the resonators are made out of the same material). However, a tuba produces Fundamental Frequencies that are generally slower (or pitches that are lower) than a trumpet produces. So if a tuba produces C32 / C1 (AKA the lowest C on the piano keyboard), there are corresponding harmonics produced with that Fundamental Frequency and there are A LOT MORE of them produced than in the C261 / C4 (AKA middle C) that the trumpet produces simply because the trumpet starts with a faster Fundamental Frequency (AKA higher pitch). SO, because there are more harmonics in the lower pitched / slower Fundamental Frequency sound, the sound is perceived as ‘richer’ or ‘darker’ - eg 2 (role of the resonator): say that same trumpet and tuba decide to meet in the middle (ish) and both play A110 / A2 (which: not actually possible for the trumpet). Even though both instruments are producing the same Fundamental Frequency (AND harmonics), the shape of the tuba prefers strengthening those lower harmonics while the shape of the trumpet prefers strengthening the higher harmonics so … the tuba’s A110 / A2 will be perceived as ‘darker’ or ‘richer’ than the trumpet’s A110 / A2.
4. Duration 28:50 Guess what? If the sound isn’t long enough (ie doesn’t have enough DURATION) for us to perceive it? It’s not a sound. #yourewelcome
BONUS MATERIAL: 29:19
References
Bozeman, Kenneth. Practical Vocal Acoustics. Press Hillside: Pendragon, 2013. Print. McCoy, Scott. Your Voice: An Inside View. Delaware: Inside View Press, 2012. Print. McCoy, Scott. Your Voice: The Basics. Gahanna: Inside View Press, 2016. EBook. McKinney, James C. The Diagnosis & Correction of Vocal Faults. Nashville: Genevox Music Group, 1982. Print. Sataloff, Robert T., ed. Vocal Health and Pedagogy Volume I. San Diego: 2006. Print. Vennard, William. Singing - the Mechanism and the Technic. New York: Carl Fischer, 1967. Print. Ware, Clifton. Basics of Vocal Pedagogy. Boston: McGraw-Hill, 1998. Print.
* And by “Cheat Sheet”, I mean: CHEAT SHEET. This is IN NO WAY comprehensive and is NOT intended to be taken as such. If you want to stop cheating, just read the books your own self already.