Reference: attributes
In CWMN noteset is typically an octave. But an "octave" can of course be divided into several different ratios. The attribute "noteset" is a more neutral term, with one possible value of "octave".
| Type | Element | Description | Use |
|---|---|---|---|
| Indicates the distance of eight scale degrees or steps between the 'white notes' in a set of notes; contains a set of notes, each of which is in a 2:1 relationship with their counterparts in another set, ie in another octave. The values of octave depends on among other things, the scale. | To specify the octave in which a note is to be rendered. |
Also see scale.
The name octave is derived from Latin referring to the eight white notes on a keyboard that form a set. Octaves are repeated cyclical at higher or lower frequencies.
Together with the 5 black notes there are 12 notes in an octave. This is only in Western tempered music. Other music systems may have only 5 notes to the "octave", or even in excess of 20 notes.
A seven-octave piano keyboard ranges in frequency from about 20Hz to 5'000Hz. There are different conventions for numbering octaves, such as the Helmholz method, (starting about in the middle of the piano keyboard and numbering outwards, thus a dual method) and the method used by music physicists (starting at one end, the lower end, and numbering serially upward).
An octave can be indicated with two methods:
When the octave number is indicated together with the note name, the number in MML precedes the note name.
As 20Hz is about the lowest audible frequency (note that lower frequencies are not so much heard as felt), numbering octaves in MML will begin with octave 0 (ie zero) at A= 27.5Hz given a certain tuning system. Conventions usually indicate the octave number as a subscript after after the note name, eg C4. This is impossible in markup code. In MML the number will precede the note name, thus middle C is 4C because it is in the 4th octave.
The octave may be declared once in the head of the song, assuming that it will not change during the course of the song. A change in octave can nevertheless be declared as a child of the song element.
The human ear is capable of hearing sounds in the range of frequencies 20Hz to 20KHz (or most likely, 17-18KHZ). Music typically ranges between 2 to 5KHz, however, the 2' pitch pipe organ reaches 8'372Kz. Harmonics of cymbals reach up to 16'000Hz (octave 9 in the table below). Here is a table showing the frequencies of A notes in different octaves, given 4A = 440HZ.
| Octave number | Helmholz number | Approximate frequencies for first A of each octave |
|---|---|---|
| 0 | 27.5Hz | |
| 1 | A, | 55Hz |
| 2 | A | 110Hz |
| 3 | a | 220Hz |
| 4 | a' | 440Hz |
| 5 | a" | 880Hz |
| 6 | a"' | 1'760Hz |
| 7 | a"" | 3'950Hz |
| 8 | "7'900Hz" | |
| 9 | "15'900Hz" | |
| Octaves 8 and 9 above are
theoretical octaves. The approximate frequencies is for a given tuning (for A = 440Hz). When A has another value (eg 442Hz), the frequencies of the other notes will also be different. |
||
In MML the information above is typically contained in a mapped file. For A=440 the filename is 440.mmm, and for A=442 the filename is 442.mmm. Also see tuning.
<bar 3 octave="4">
</bar>
...
<song octave="4">
...
</song>
...
Here are a few C notes in different octaves.
5C
3C
2C
7C
<bar 21 octave="3">A 4A 2A A
Read: there are four A notes each on a different beat. A on beats 1 and 4 are on octave 3; the second beat on octave 4, the third on octave 2.
© 1999, 2000 Author: Jacques Steyn