Semi-log plot: Difference between revisions

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'''MIDI Tuning Standard (MTS)''' is a specification of precise [[musical pitch]] agreed to by the [[MIDI Manufacturers Association]] in the [[MIDI]] protocol. MTS allows for both a bulk tuning dump message, giving a tuning for each of 128 [[notes]], and a tuning message for individual notes as they are played.
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==Frequency values==
If ''ƒ'' is a [[frequency]], then the corresponding frequency data value ''d'' may be computed by
 
:<math>d = 69 + 12 \log_2 \left(\frac {f}{440\ \mathrm{Hz}}\right).\,</math>
 
The quantity log<sub>2</sub>&nbsp;(''&fnof;''&nbsp;/&nbsp;440&nbsp;Hz) is the number of [[octaves]] above the 440-Hz [[concert A]] (it is negative if the frequency is below that pitch). Multiplying it by 12 gives the number of [[semitones]] above that frequency.  Adding 69 gives the number of semitones above the C five octaves below [[middle C]].
 
Since 440 [[hertz|Hz]] is a widely used standard concert A (e.g. USA, UK), and since that is represented in MIDI terms by the integer 69 (nine semitones above middle C, which is 60), this gives a real number which expresses pitch in a manner consistent with MIDI and [[integer notation]], known as the midi note number.  
 
Converting from midi note number (d) to frequency (f) is given by the following formula:
 
:<math>f = 2^{(d-69)/12} \cdot 440\ \mathrm{Hz} \, </math>
 
==Frequency Data Format==
The frequency data format allows for the precise notation of frequencies that differ from [[equal temperament]].
 
 
"Frequency data shall be defined in [units] which are fractions of a semitone. The frequency range starts at MIDI note 0, C = 8.1758 Hz, and extends above MIDI note 127, G = 12543.875 Hz. The first byte of the frequency data word specifies the highest equal-tempered semitone not exceeding the frequency. The next two bytes (14 bits) specify the fraction of 100 cents above the semitone at which the frequency lies. Effective resolution = 100 cents / 2<sup>14</sup> = .0061 cents."<ref name="refname1" />
 
This higher resolution allows a logarithmic representation of pitch in which the semitone is divided into 128<sup>2</sup> = 2<sup>14</sup> = 16384 parts, which means the octave is divided into 196608 (logarithmically) equal parts. These parts are exactly 100/16384 cents (approximately 0.0061 cents) in size, which is far below the threshold of [[hearing range | human pitch perception]] and which therefore allows a very accurate representation of pitch.
 
==Applications==
The precision pitch values may be used in [[microtonal music]], [[just intonation]], [[meantone temperament]], or other alternative tunings. Software which supports MTS includes [[Scala (program)|Scala]], [[TiMidity++]], [[alt-tuner]], [[L'il Miss Scale Oven]], [[Tune Smithy]], [[Max Magic Microtuner]], [[Gervill]]. Software plugin instruments which support MTS include [[Native Instruments]] [[FM8]], Synthogy Ivory, and Xen-Arts' various xenharmonic VSTi plugins, including the FMTS FM synthesizer, Ivor virtual analog synthesizer, and XenFont SoundFont sample player.
 
==References==
{{Reflist|refs=
<ref name="refname1">Midi Manufacturers Association, Midi Tuning Specification ( http://www.midi.org/techspecs/midituning.php )</ref>
}}
 
==See also==
*[[Microtonal music]]
*[[Microtuner]]
*[[Musical tuning]]
 
==External links==
===MTS specification===
* [http://www.midi.org/about-midi/tuning.shtml MTS specification]
* [http://www.midi.org/about-midi/specinfo.shtml Detailed MTS specification]
* [http://www.midi.org/about-midi/tuning_extens.shtml MTS extensions]
 
===Microtonal music software supporting MTS===
* [http://www.huygens-fokker.org/scala/ Scala (Windows, Linux, Mac)]
* [http://www.tallkite.com/alt-tuner.html alt-tuner (Windows, Linux, Mac)]
* [http://timidity.sourceforge.net/ TiMidity++ (Windows, Linux, Mac)]
* [http://www.robertinventor.com/software/tunesmithy/music.htm Tune Smithy (Windows)]
* [http://www.xen-arts.com/ Xen-Arts Microtonal MIDI Software (Windows VSTi)]
 
===Inactive links===
* [http://www.nonoctave.com/tuning/LilMissScaleOven/ L'il Miss' Scale Oven (Mac)]
* [https://gervill.dev.java.net/ Gervill (Windows, Linux, Mac)]
 
[[Category:Computer file formats]]
[[Category:Electronic music]]
[[Category:MIDI standards]]
[[Category:MIDI]]
[[Category:Music notation file formats]]
[[Category:Musical tuning]]

Latest revision as of 21:46, 4 December 2014

Oscar is what my spouse enjoys to contact me and I totally dig that name. Her family life in Minnesota. My working day occupation is a meter reader. Doing ceramics is what her family members and her enjoy.

Stop by my blog ... http://xrambo.com/user/RKDBG