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{{Wikipedia|Major third}} | {{Wikipedia|Major third}} | ||
In [[5-limit]] [[just intonation]], '''5/4''' is the [[frequency ratio]] between the 5th and 4th [[harmonic]]s. It has been called the '''just major third''', '''classic(al) major third''', or '''ptolemaic major third'''<ref>For reference, see [[5-limit]].</ref> to distinguish it from other intervals in that neighborhood. Measuring about 386.3 [[cent|¢]], it is about 13.7 ¢ away from [[12edo]]'s major third of 400 ¢. It has a distinctive "sweet" sound, and has been described as more "laid back" than its 12edo counterpart. Providing a novel consonance after 3, it is the basis for [[5-limit]] harmony. It is distinguished from the [[Pythagorean]] major third of [[81/64]] by the syntonic comma of [[81/80]], which measures about 21.5 ¢. 81/64 and 5/4 are both just intonation "major thirds", 81/64 having a more active and discordant quality, 5/4 sounding more "restful". | In [[5-limit]] [[just intonation]], '''5/4''' is the [[frequency ratio]] between the 5th and 4th [[harmonic]]s. It has been called the '''just major third''', '''classic(al) major third''', or '''ptolemaic major third'''<ref>For reference, see [[5-limit]].</ref> to distinguish it from other intervals in that neighborhood. Measuring about 386.3 [[cent|¢]], it is about 13.7 ¢ away from [[12edo]]'s major third of 400 ¢. It has a distinctive "sweet" sound, and has been described as more "laid back" than its 12edo counterpart. Providing a novel consonance after 3, it is the basis for [[5-limit]] harmony. It is distinguished from the [[Pythagorean]] major third of [[81/64]] by the syntonic comma of [[81/80]], which measures about 21.5 ¢. 81/64 and 5/4 are both just intonation "major thirds", 81/64 having a more active and discordant quality, 5/4 sounding more "restful". It is a [[schisma]] sharp of 8192/6561, another 3-limit interval in the major third range often called a diminished fourth. | ||
In the context of the harmonic series, 5/4 can be heard between the 4th and 5th member of the series, demonstrated in [[:File: 5-4.mp3]] melodically in singing into a resonant [[udderbot]] (from the fundamental up to 5 and then noodling between 5 and 4). | In the context of the harmonic series, 5/4 can be heard between the 4th and 5th member of the series, demonstrated in [[:File: 5-4.mp3]] melodically in singing into a resonant [[udderbot]] (from the fundamental up to 5 and then noodling between 5 and 4). |
Revision as of 08:44, 16 April 2025
Interval information |
classic(al) major third,
ptolemaic major third
reduced,
reduced harmonic
[sound info]
In 5-limit just intonation, 5/4 is the frequency ratio between the 5th and 4th harmonics. It has been called the just major third, classic(al) major third, or ptolemaic major third[1] to distinguish it from other intervals in that neighborhood. Measuring about 386.3 ¢, it is about 13.7 ¢ away from 12edo's major third of 400 ¢. It has a distinctive "sweet" sound, and has been described as more "laid back" than its 12edo counterpart. Providing a novel consonance after 3, it is the basis for 5-limit harmony. It is distinguished from the Pythagorean major third of 81/64 by the syntonic comma of 81/80, which measures about 21.5 ¢. 81/64 and 5/4 are both just intonation "major thirds", 81/64 having a more active and discordant quality, 5/4 sounding more "restful". It is a schisma sharp of 8192/6561, another 3-limit interval in the major third range often called a diminished fourth.
In the context of the harmonic series, 5/4 can be heard between the 4th and 5th member of the series, demonstrated in File: 5-4.mp3 melodically in singing into a resonant udderbot (from the fundamental up to 5 and then noodling between 5 and 4).
Approximations by edos
Following edos (up to 200, and also 643) contain good approximations[2] of the interval 5/4. Errors are given by magnitude, the arrows in the table show if the edo representation is sharp (↑) or flat (↓).
Edo | deg\edo | Absolute error (¢) |
Relative error (r¢) |
↕ | Equally acceptable multiples [3] |
---|---|---|---|---|---|
25 | 8\25 | 2.3137 | 4.8202 | ↓ | |
28 | 9\28 | 0.5994 | 1.3987 | ↓ | 18\56, 27\84, 36\112, 45\140 |
31 | 10\31 | 0.7831 | 2.0229 | ↑ | 20\62, 30\93 |
34 | 11\34 | 1.9216 | 5.4445 | ↑ | |
53 | 17\53 | 1.4081 | 6.2189 | ↓ | |
59 | 19\59 | 0.1270 | 0.6242 | ↑ | 38\118, 57\177 |
87 | 28\87 | 0.1068 | 0.7744 | ↓ | 56\174 |
90 | 29\90 | 0.3530 | 2.6471 | ↑ | 58\180 |
115 | 37\115 | 0.2268 | 2.1731 | ↓ | |
121 | 39\121 | 0.4631 | 4.6701 | ↑ | |
143 | 46\143 | 0.2997 | 3.5718 | ↓ | |
146 | 47\146 | 0.0123 | 0.1502 | ↓ | |
149 | 48\149 | 0.2635 | 3.2714 | ↑ | |
152 | 49\152 | 0.5284 | 6.6930 | ↑ | |
171 | 55\171 | 0.3488 | 4.9704 | ↓ | |
199 | 64\199 | 0.3841 | 6.3691 | ↓ | |
643 | 207\643 | 0.0004 | 0.0235 | ↑ |
See also
- 8/5 – its octave complement
- 6/5 – its fifth complement
- 16/15 – its fourth complement
- 5/2 – the interval up one octave which sounds even more consonant
- Ed5/4
- Gallery of just intervals
- List of superparticular intervals