Tutorial 2

Question 1

What is 5 prime limit just intonation?

Answer 1

notes are derived from the root note by multiplying by powers of prime numbers up to 5.

Question 2

What are the first 5 ratios in the pythagorean scale?

Answer 2

1:1, 3:2, 9:8, 27:16, 81:64

Question 3

What is the difference between a scale with just intonation and a tempered scale?

Answer 3

in a just intonated scale, the intervals are ratios of whole numbers
in a tempered scale, the positions of the notes are adjusted from just intonation, usually to make a scale with more uniform intervals

Question 4

Explain the diatonic scale.

Answer 4

7 notes with different intervals, 5 tones and 2 semitones

Question 5

explain the chromatic scale

Answer 5

12 notes with equal intervals, all semitones

Question 6

What does 12-EDO mean?

Answer 6

12 Equal Divisions of the Octave.

Question 7

What are some advantages of the 12 tone equal tempered scale (12-EDO)?

Answer 7

• all intervals are equal
• offers the opportunity for 12 different diatonic scales, with overlapping notes
• allows movement between key changes

Question 8

What are some disadvantages of 12-EDO?

Answer 8

• many intervals far from just in the chromatic scale
• even in the diatonic scales, some intervals are not very close to just diatonic intonation.

Question 9

How is sound generated in a guitar, violin or piano?

Answer 9

• guitar -> plucking
• violin -> bowing
• piano -> hammering

Question 10

How are the different notes made in a guitar, violin or piano?

Answer 10

• guitar -> pressing frets
• violin -> pressing directly
• piano -> each note on a different string

Question 11

What scale does the guitar, violin or piano have?

Answer 11

• guitar -> chromatic
• violin -> any
• piano -> chromatic

Question 12

How many octaves do the guitar, violin and piano have?

Answer 12

• g-> 4
• v -> 4
• p -> 7

Question 13

How polyphonic are the guitar, violin and piano?

Answer 13

• g -> max. 6 notes
• v -> max. 2 notes
• p -> lots, with sustain pedal

Question 14

How do bowed instruments work?

Answer 14

• allow for continuous input of energy, which means they can have very high volume, good dynamic range, and excellent control of sound.
• basically monophonic
• most are non-fretted, allowing any scale to be used
• harmonics excited on bowed instruments are also quite different to those excited on plucked and hammered instruments

Question 15

how to plucked instruments work?

Answer 15

• generally played with fingers or a pick, which gives good control of attack
• amount of energy that can be input with plucking action is limited so they are much quieter than bowed instruments
• reasonably high polyphony

Question 16

Explain stick-slip motion.

Answer 16

• depends on friction between bow and string
• kinetic friction -> force between surfaces moving relative to each other
• static friction -> force between surfaces not moving
• when the bow moves over the unstretched string, it sticks (static) and stretches, moving with the bow until the restorting force from stretching overcomes the friction, causing it to slip back. When it slows down it is picked up again by the bow (static) and the cycle repeats

Question 17

What is an example of an open-open instrument?

Answer 17

flute

Question 18

what are some examples of open-closed instruments?

Answer 18

clarinet, oboe, trumpet

Question 19

What is the reed type for the flute, and how does it work?

Answer 19

no reed/air reed
a stream of air is split evenly at the far edge of the opening, causing pressure oscillations.

Question 20

what is the reed type for the oboe, and how does it work?

Answer 20

double reed
- air pressure variations between two reeds are caused by Bernouille effect, causing the reeds to oscillate

Question 21

what is the reed type in the saxophone, and how does it work?

Answer 21

Single reed
- air pressure variations between reed and mouthpiece are caused by the Bernouille effect, whihc casues the reed to oscillate

Question 22

How can you change the pitch of a note on a woodwind instrument?

Answer 22

• changing the length of the pipe by covering tone holes, which changes the fundamental and harmonics by the same factor
• playing in a higher register (overblowing) to bypass the fundamental and play the higher harmonics

Question 23

What is the term for brass instruments?

Answer 23

lip reed instruments

Question 24

how is sound produced in a lip reed instrument?

Answer 24

air is blown through the lips, forcing them apart, where the high velocity of the air stream pulls them back together again via the Bernouille effect, causing them to oscillate and send a stream of air with oscillating pressure down the instrument.

Question 25

How can you change the pitch of a note on a brass instrument?

Answer 25

• changing the length of the pipe by
  opening/closing valves or moving a slide
• playing in a higher register (overblowing)
• lipping -> forcing a note using the player’s embouchure to adjust the interplay between the tube resonances and mouthpiece resonance.

Question 26

What features of a brass instrument allow even harmonics to be played, even though the instruments are open-close?

Answer 26

• taper and bell -> modify resonances to form a harmonic series with strong radiation of higher harmonics from the bell
• mouthpiece has its own resonance
• player’s embouchure