Hochschild homology: Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
en>Justincheng12345-bot
 
en>Mark viking
Added wl
 
Line 1: Line 1:
Hi there, I am Felicidad Oquendo. I am a production and distribution officer. The thing she adores most is flower arranging and she is trying to make it a occupation. Delaware is our beginning location.<br><br>Feel free to visit my webpage - car warranty ([http://www.gauhaticommercecollege.in/content/dont-allow-auto-repair-best-you Learn Alot more Here])
{{multiple issues|
{{Refimprove|date=May 2008}}
{{missing information| the practical use of MIDI|date=July 2012}}
{{context|date=July 2012}}
{{inadequate lead|date=July 2012}}
}}
The two organizations responsible for the creation and oversight of the [[The MIDI 1.0 Protocol|MIDI standard]], the US [[MIDI Manufacturers Association]] (MMA) and Japan's [[Association of Musical Electronics Industry]] (AMEI), have jointly standardized many extensions to it. [[General MIDI]] (GM) is one of these, an attempt by the MMA to create a standardized map of instrument programme numbers. AMEI members developed [[General MIDI Level 2]] (GM2), which increased the number of available instruments, specified additional message responses, and defined new messages. GM2 is the basis of the instrument selection mechanism in Scalable Polyphony MIDI (SP-MIDI), a MIDI variant for mobile applications. The hardware connection specified in the original standard has been augmented with support for additional forms of transport. MIDI is also used as a control protocol in applications other than music, including [[show control]] and [[theatre lighting]].
 
== Extensions of the MIDI standard ==
 
Only a few extensions of the original official [[The MIDI 1.0 Protocol|MIDI 1.0 specification]] are described here; for more comprehensive information, see the [http://www.midi.org/ MMA web site].
 
===General MIDI===
 
The [[General MIDI]] (GM) and [[General MIDI Level 2|General MIDI 2]] (GM2) standards specify how a MIDI device will respond when it receives a defined set of MIDI messages. These standards ensure that a MIDI stream will be played in a consistent manner on any conformant instrument.  The GM and GM2 specifications are dependent on the basic MIDI 1.0 specification, but separate from it, so that is not generally safe to assume that any given MIDI message stream or MIDI file will be handled in the expected way by GM-compliant or GM2-compliant MIDI instruments.
 
These specifications resolve ambiguities in the MIDI message protocol. In MIDI, instruments are arranged one-per-channel, and are selected by program change messages using the numbers 0-127. MIDI 1.0 does not define which instrument sound (piano, tuba, etc.) corresponds to each number. This was due to MIDI's origin as a professional music protocol, and was intended to allow a performer to assemble a custom palette of instruments appropriate for their particular repertoire.
 
MIDI was later adopted as a consumer content format, and for computer multimedia applications. In order for MIDI file content to be portable, the instrument program numbers used must call up the same instrument sound on every player. The MMA addressed this problem with the 1991 introduction of GM. GM standardises an instrument programme number map, which specifies that a given program change number will select the same instrument sound on every GM-compatible device. For example, a program change message with a value of "1" results in a piano sound on all GM-compliant players. GM also specified the response to certain other MIDI messages in a more controlled manner than the MIDI 1.0 specification. The GM spec is maintained and published by the MMA.
 
GM has a mixed reputation, mainly because of audible differences between instrument sounds across player implementations, the limited size of the instrument palette (128 instruments), and the inability to add customised instruments to suit the needs of the particular piece. The GM instrument set is nevertheless included in most MIDI instruments, and GM has proven to be a durable standard.
 
===General MIDI 2===
 
Companies in Japan's AMEI later developed General MIDI Level 2 (GM2), which incorporated aspects of the Yamaha [[XG (midi)|XG]] and Roland [[General MIDI#GS extensions|GS]] formats. GM2 provides for expansion of the instrument palette, specifies more message responses in detail, introduces messages that allow custom tuning scales, and more. The GM2 specs are maintained and published by the MMA and AMEI. General MIDI 2 was introduced in 1999, and last amended in February 2007.
 
===SP-MIDI===
 
GM2 is the basis of the instrument selection mechanism in Scalable Polyphony MIDI (SP-MIDI), a MIDI variant for mobile applications in which different players may have different numbers of musical voices. SP-MIDI is a component of the 3GPP mobile phone terminal multimedia architecture, as of release 5. GM, GM2, and SP-MIDI are also the basis for the selection of player-provided instruments in several MMA/AMEI XMF file formats (XMF Type 0, Type 1, and Mobile XMF), which allow the instrument palette to be extended with custom instruments in the Downloadable Sound (DLS) formats. This addresses GM's lack of support for customized instruments.
 
===Alternate Hardware Transports===
 
In addition to the original 31.25 kBaud current-loop signal that terminates in a [[DIN connector|5-pin DIN]] connector, transmission of MIDI streams over [[Universal Serial Bus|USB]], IEEE 1394/[[FireWire]] and [[Ethernet]] is now common.
 
===MIDI over Ethernet===
The Ethernet implementation of MIDI provides useful network routing capabilities which are not possible with the peer-to-peer USB and FIreWire technologies.{{dubious|date=August 2012}}
Ethernet is moreover capable of providing the high-bandwidth channel that earlier alternatives to MIDI (such as [[ZIPI]]) were intended to bring.
After an initial [[Format war|battle among competing protocols]], the RTP-MIDI specification for transport of MIDI over [[Ethernet]] and the [[Internet]] is gaining industry support. Drivers available for the Macintosh, Windows and Linux operating systems allow RTP-MIDI devices to be addressed as standard MIDI devices.
 
 
===RTP-MIDI Transport Protocol===
{{main|RTP MIDI}}
The [[RTP MIDI]] protocol was released to the public domain by [[IETF]] in December 2006 (RFC 4695), and was supplanted in June 2011 by RFC 6295, which corrects the original's errors. RTP-MIDI relies on the  [[Real-time Transport Protocol]] (RTP) layer that is in wide use for real-time audio and video streaming over networks. The RTP layer is lightweight and easy to implement, and provides the receiver with useful information regarding the network state. RTP-MIDI defines a specific payload type that allows the receiver to identify MIDI streams. It transports MIDI messages unaltered, but adds functionalities such as timestamping and sysex fragmentation, and journaling, which allows the receiver to detect the loss of MIDI messages in the network and to retrieve lost information.
 
The first part of the RTP-MIDI specification describes how MIDI messages are encapsulated within the RTP telegram, and describes how the journaling system works. Use of the journaling system is not mandatory, as journaling is not useful for LAN applications, but is important for WAN applications. The second part of the specification describes the session control mechanisms that allow multiple stations to synchronize across the network to exchange RTP-MIDI telegrams. This part is informational only, and it is not required that all RTP-MIDI implementations use the described mechanisms.
 
RTP-MIDI has been included in Apple's [[Mac OS X]] since 10.4 and [[IOS (Apple)|iOS]] since 4.2 as standard MIDI ports. The RTP-MIDI ports appear in Macintosh applications as any other USB or FireWire port, so any MIDI application running on Mac OS X is able to use the RTP-MIDI capabilities in a transparent way. Apple's developers have created their own session control protocol, as they felt the one described in IETF's specification was too complex. Since the session protocol uses a different UDP port of the main RTP-MIDI stream port, the two protocols do not interfere, and the RTP-MIDI implementation in Mac OS X fully complies to the IETF specification.
 
Apple's implementation has been used as a reference by other MIDI manufacturers.  A [[Microsoft Windows|Windows]] RTP-MIDI driver<ref>[http://www.tobias-erichsen.de/rtpMIDI.html Windows RTP-MIDI driver download]</ref> compatible with Windows XP through Windows 7 (32bit and 64bit) has been released, the Dutch company [[Kiss-Box]] has produced a [[Microsoft Windows|Windows]] XP RTP-MIDI driver for their own devices, and a Linux implementation is under development by the [[Grame]] association. It is probable that Apple's implementation will become the "de facto" standard, and could even become the MMA reference implementation.
 
===Alternate Tunings===
 
Instruments that receive MIDI conventionally use the 12-pitch per octave equal temperament tuning system, which renders music that depends on a different intonation system inaccessible. The MMA addressed this issue with the 1992 ratification of the [[MIDI Tuning Standard]], or MTS. MIDI instruments that support MTS can be tuned in any way desired, through the use of a MIDI Non-Real Time System Exclusive message.
 
MTS specifies a pitch in logarithmic form through a three byte message which can be thought of as a three-digit number in base 128. The byte values necessary to encode a given frequency in hertz are determined by the following formula:
 
:<math>p = 69 + 12\times\log_2 { \left(\frac {f}{440} \right) }</math>
 
For a note in A440 equal temperament, this formula delivers the standard MIDI note number. Other frequencies fill the space evenly.
 
Support for MTS is not particularly widespread in commercial hardware instruments. Programs that support MTS include the [[free software]] programs [[TiMidity]] and [[Scala (program)|Scala]], as well as other [[microtuner]]s.
 
== Other applications of MIDI ==
 
MIDI is also used every day as a control protocol in applications other than music, including:
* [[show control]]
* [[theatre lighting]]
* [[special effects]]
* [[sound design]]
* [[Console automation]]
* [[recording system synchronization]]
* [[audio processor control]]
* [[Computer animation|computer]] [[Animusic|animation]]
* computer networking, as demonstrated in 1987 by the early [[first-person shooter]] game ''[[MIDI Maze]]''
* animatronic figure control
 
Non-musical applications of MIDI are possible because any device built with a standard MIDI Out connector should in theory be able to control any other device with a MIDI In port, as long as the developers of both devices agree on the meaning of the MIDI messages the sending device emits. This agreement can come either because both follow the published MIDI specifications, or in the case of non-standard functionality, because the message meanings are agreed upon by the two manufacturers.
 
==MIDI controllers==
 
The term "MIDI controller" is used in two different ways. A MIDI controller can be defined as hardware or software that is able to transmit MIDI messages via a MIDI Out connector to other devices with MIDI In connectors. In the other, more technical sense, a MIDI controller is a parameter that can be controlled remotely through MIDI Control Change messages. For example, synthesizers commonly use controller number 74 to control a low-pass filter's frequency. If a user assigns a physical slider to transmit controller number 74, then all changes in the slider position will be transmitted as MIDI Control Change messages on controller number 74, and the synthesizer's filter frequency will change accordingly.
 
===MIDI controllers which are hardware and software===
 
The following are types of MIDI controller, according to definition 1 above:
 
*The human interface component of a traditional instrument, redesigned as a MIDI output device. Most commonly, the keyboard controller. Such a device provides a [[musical keyboard]], and often other actuators such as pitch bend and modulation wheels, but produces no sound on its own and is intended only to drive other MIDI devices. Percussion controllers such as the [[Roland Octapad]] fall into this class, as do guitar-like controllers such as the [[SynthAxe]], and a variety of wind controllers.
 
*[[Electronic musical instrument]]s, including [[synthesizer]]s, [[sampler (musical instrument)|sampler]]s, [[drum machine]]s, and [[electronic drum]]s, which are used to perform music in real time and are able to transmit a MIDI data stream of the performance.
 
*Pitch-to-MIDI converters such as [[guitar synthesizer]]s analyze a pitch and convert it into a MIDI signal. Several devices do this for the human voice and for monophonic instruments such as flutes.
 
*Traditional instruments such as [[drum kit|drum]]s, [[piano]]s, and [[accordion]]s that are outfitted with sensors, whose output is processed and transmitted as MIDI data.
 
*[[music sequencer|Sequencer]]s, which store and retrieve MIDI data, and then send the data to MIDI-enabled instruments in order to reproduce a performance.
 
* The [[MIDI Show Control]] (MSC) protocol is an industry standard, ratified in 1991 by the [[MIDI Manufacturers Association]], which allows all types of media control devices to work together to perform [[show control]] functions in live and recorded [[entertainment]] applications. Just as in musical MIDI, MSC does not transmit the actual show media, but instead transmits digital data containing information such as the type, timing and numbering of technical [[Cue (theatrical)|cues]] called during a [[multimedia]] or live [[theatre]] performance.
 
*[[MIDI Machine Control]] (MMC) devices such as recording equipment, which transmit messages for synchronization of MIDI-enabled devices. For example, a recorder that has a feature to index a recording by measure and beat can be synchronized with a sequencer.
 
===MIDI controllers in the data stream===
 
This section uses the second definition of "MIDI controller".
 
Performance modifier controls such as modulation wheels, pitch bend wheels and [[ribbon controller]]s alter an instrument's state of operation, and can be used to modify sounds or other parameters of a musical device. MIDI includes messages that represent such controller events, and they can be sent in real time over MIDI connections. MIDI makes approximately 120 virtual controller numbers available for this purpose. The value data range of the MIDI Control Change message is 128 steps (0 to 127). The first 32 controller numbers are allocated an additional 7 bits of precision for a total of 14 bits, which provides a range of 0-16383, although many manufacturers do not implement this increased resolution.
 
Some controller functions, such as pitch bend or key pressure, are given a dedicated MIDI data range of 16,384 steps. This higher resolution makes it possible to produce the illusion of a continuously sliding pitch, as in a violin's portamento, rather than a series of zippered steps, such as a guitarist sliding fingers up the frets of the guitar's neck. Pitch bend and key velocity use different, dedicated messages, such as Polyphonic Key Pressure, Channel Pressure, or Pitch Bend Change, rather than the ordinary Control Change message. There is a disadvantage, in that the pitch wheel and/or key pressure functions of a MIDI keyboard can generate large amounts of data that can lead to a slowdown of data throughput on the MIDI connection. This can be remedied by using a sequencer to filter continuous controller data down to a limited number of messages per second, or to messages that change the controller value by a minimum amount.
 
The original MIDI specification included approximately 120 virtual controller numbers for real-time modifications of live instruments or their audio. MSC and MMC are two separate extensions of the original MIDI specification, and expand the MIDI protocol beyond its original intent.
 
==See also==
*[[Mobile phone ringtone]]
*[[Pulse-code modulation]] (PCM)
*[[show control]]
 
==References==
<references />
 
{{DEFAULTSORT:Midi Usage And Applications}}
[[Category:MIDI]]

Latest revision as of 04:59, 13 January 2014

Template:Multiple issues The two organizations responsible for the creation and oversight of the MIDI standard, the US MIDI Manufacturers Association (MMA) and Japan's Association of Musical Electronics Industry (AMEI), have jointly standardized many extensions to it. General MIDI (GM) is one of these, an attempt by the MMA to create a standardized map of instrument programme numbers. AMEI members developed General MIDI Level 2 (GM2), which increased the number of available instruments, specified additional message responses, and defined new messages. GM2 is the basis of the instrument selection mechanism in Scalable Polyphony MIDI (SP-MIDI), a MIDI variant for mobile applications. The hardware connection specified in the original standard has been augmented with support for additional forms of transport. MIDI is also used as a control protocol in applications other than music, including show control and theatre lighting.

Extensions of the MIDI standard

Only a few extensions of the original official MIDI 1.0 specification are described here; for more comprehensive information, see the MMA web site.

General MIDI

The General MIDI (GM) and General MIDI 2 (GM2) standards specify how a MIDI device will respond when it receives a defined set of MIDI messages. These standards ensure that a MIDI stream will be played in a consistent manner on any conformant instrument. The GM and GM2 specifications are dependent on the basic MIDI 1.0 specification, but separate from it, so that is not generally safe to assume that any given MIDI message stream or MIDI file will be handled in the expected way by GM-compliant or GM2-compliant MIDI instruments.

These specifications resolve ambiguities in the MIDI message protocol. In MIDI, instruments are arranged one-per-channel, and are selected by program change messages using the numbers 0-127. MIDI 1.0 does not define which instrument sound (piano, tuba, etc.) corresponds to each number. This was due to MIDI's origin as a professional music protocol, and was intended to allow a performer to assemble a custom palette of instruments appropriate for their particular repertoire.

MIDI was later adopted as a consumer content format, and for computer multimedia applications. In order for MIDI file content to be portable, the instrument program numbers used must call up the same instrument sound on every player. The MMA addressed this problem with the 1991 introduction of GM. GM standardises an instrument programme number map, which specifies that a given program change number will select the same instrument sound on every GM-compatible device. For example, a program change message with a value of "1" results in a piano sound on all GM-compliant players. GM also specified the response to certain other MIDI messages in a more controlled manner than the MIDI 1.0 specification. The GM spec is maintained and published by the MMA.

GM has a mixed reputation, mainly because of audible differences between instrument sounds across player implementations, the limited size of the instrument palette (128 instruments), and the inability to add customised instruments to suit the needs of the particular piece. The GM instrument set is nevertheless included in most MIDI instruments, and GM has proven to be a durable standard.

General MIDI 2

Companies in Japan's AMEI later developed General MIDI Level 2 (GM2), which incorporated aspects of the Yamaha XG and Roland GS formats. GM2 provides for expansion of the instrument palette, specifies more message responses in detail, introduces messages that allow custom tuning scales, and more. The GM2 specs are maintained and published by the MMA and AMEI. General MIDI 2 was introduced in 1999, and last amended in February 2007.

SP-MIDI

GM2 is the basis of the instrument selection mechanism in Scalable Polyphony MIDI (SP-MIDI), a MIDI variant for mobile applications in which different players may have different numbers of musical voices. SP-MIDI is a component of the 3GPP mobile phone terminal multimedia architecture, as of release 5. GM, GM2, and SP-MIDI are also the basis for the selection of player-provided instruments in several MMA/AMEI XMF file formats (XMF Type 0, Type 1, and Mobile XMF), which allow the instrument palette to be extended with custom instruments in the Downloadable Sound (DLS) formats. This addresses GM's lack of support for customized instruments.

Alternate Hardware Transports

In addition to the original 31.25 kBaud current-loop signal that terminates in a 5-pin DIN connector, transmission of MIDI streams over USB, IEEE 1394/FireWire and Ethernet is now common.

MIDI over Ethernet

The Ethernet implementation of MIDI provides useful network routing capabilities which are not possible with the peer-to-peer USB and FIreWire technologies.To succeed in selling a home, it is advisable be competent in real estate advertising and marketing, authorized, monetary, operational aspects, and other information and skills. This is essential as a result of you want to negotiate with more and more sophisticated buyers. You could outperform rivals, use latest technologies, and stay ahead of the fast altering market.

Home is where the center is, and choosing the right house is a part of guaranteeing a contented expertise in Singapore. Most expats sign up for a two-year lease with the option to resume, so it is value taking the time to choose a neighbourhood that has the services you want. The experts at Expat Realtor have compiled the next data that will help you negotiate your means by way of the property minefield. Some government state properties for rent. Over 2000 units available for lease however occupancy is often excessive. Some properties come under a bidding system. Their property brokers embody DTZ and United Premas. Up to date serviced residences located just off Orchard Highway. one hundred sixty Orchard Highway, #06-01 Orchard Level, Singapore 238842. Institute Of Property Agents

There is no such thing as a deal too small. Property agents who're willing to find time for any deal even when the commission is small are those you want in your side. They also show humbleness and might relate with the average Singaporean higher. Relentlessly pursuing any deal, calling prospects even without being prompted. Even when they get rejected a hundred times, they still come back for more. These are the property brokers who will find consumers what they want finally, and who would be the most profitable in what they do. four. Honesty and Integrity

As a realtor, you're our own business. Due to this fact, it is imperative that you handle yours prices and spend money correctly in order to market your property successfully. Also, beware of mentors who always ask you to pay for pointless costs. Such mentors typically are recruiting to develop a staff and see you as a option to defray advertising and marketing prices. For foreigners who want to register with CEA as salespersons, they might want to have a valid Employment Cross (EP) issued by the Ministry of Manpower (MOM). They should consult an property agent that is ready to assist their future registration software, who would then examine with CEA. Thereafter, after they register for the RES Course, they might want to produce a letter of assist from the property agent."

Main Real Property Brokers with in depth local knowledge, Carole Ann, Elizabeth and their group of extremely skilled property consultants provide a personalised service, for those looking to buy, lease or promote in Singapore. Relocation companies out there. Properties for the aesthete. Boutique real property agency for architecturally distinguished, unique properties for rent and on the market. Caters to the niche market of design-savvy people. Sale, letting and property management and taxation services. three Shenton Means, #10-08 Shenton Home, Singapore 068805. Buy property, promote or leasing estate company. 430 Lorong 6 Toa Payoh, #08-01 OrangeTee Constructing, Singapore 319402. HIGH Date / Age of property Estate Agents and Home Search Services Property Information Highlights Prime Achievers

From the above info, you may see that saving on agent's commission will not cover the expenses wanted to market your home efficiently. As well as, it's essential make investments a whole lot of time, vitality and effort. By taking yourself away from your work and other endeavors, additionally, you will incur unnecessary opportunity prices. There may be additionally no assurance you could beat the market and get the outcomes you need. That is why you want an agent - not simply an ordinary agent - you want knowledgeable and competent specialist, geared up with the best instruments and knowledge to serve you and lead you to success! Within the midst of this ‘uniquely Singapore' Property GSS, our most needed foreign customers are nowhere to be seen. Different types of Public Residential properties

Based on Kelvin, other agents may also make use of your agent's listings. "If your pricing is on the excessive aspect, these brokers may use your house to persuade their patrons why Http://Trafficstooges.Com/Singapore-Property-Condominium they should purchase another residence." To counter this, Kelvin says it is crucial for your agent to supply a current market analysis before putting up your private home for sale. "This helps you worth your property appropriately and realistically." When property is made accessible (HIGH is issued) to the client. Becoming a successful property agent is a distinct story altogether! Hi, I would like to ask how I might be a property agent and whether there are courses I might take. And if I need to be at a certain age. www. Property BUYER com.sg (your impartial Mortgage Advisor) In private properties in Ethernet is moreover capable of providing the high-bandwidth channel that earlier alternatives to MIDI (such as ZIPI) were intended to bring. After an initial battle among competing protocols, the RTP-MIDI specification for transport of MIDI over Ethernet and the Internet is gaining industry support. Drivers available for the Macintosh, Windows and Linux operating systems allow RTP-MIDI devices to be addressed as standard MIDI devices.


RTP-MIDI Transport Protocol

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The RTP MIDI protocol was released to the public domain by IETF in December 2006 (RFC 4695), and was supplanted in June 2011 by RFC 6295, which corrects the original's errors. RTP-MIDI relies on the Real-time Transport Protocol (RTP) layer that is in wide use for real-time audio and video streaming over networks. The RTP layer is lightweight and easy to implement, and provides the receiver with useful information regarding the network state. RTP-MIDI defines a specific payload type that allows the receiver to identify MIDI streams. It transports MIDI messages unaltered, but adds functionalities such as timestamping and sysex fragmentation, and journaling, which allows the receiver to detect the loss of MIDI messages in the network and to retrieve lost information.

The first part of the RTP-MIDI specification describes how MIDI messages are encapsulated within the RTP telegram, and describes how the journaling system works. Use of the journaling system is not mandatory, as journaling is not useful for LAN applications, but is important for WAN applications. The second part of the specification describes the session control mechanisms that allow multiple stations to synchronize across the network to exchange RTP-MIDI telegrams. This part is informational only, and it is not required that all RTP-MIDI implementations use the described mechanisms.

RTP-MIDI has been included in Apple's Mac OS X since 10.4 and iOS since 4.2 as standard MIDI ports. The RTP-MIDI ports appear in Macintosh applications as any other USB or FireWire port, so any MIDI application running on Mac OS X is able to use the RTP-MIDI capabilities in a transparent way. Apple's developers have created their own session control protocol, as they felt the one described in IETF's specification was too complex. Since the session protocol uses a different UDP port of the main RTP-MIDI stream port, the two protocols do not interfere, and the RTP-MIDI implementation in Mac OS X fully complies to the IETF specification.

Apple's implementation has been used as a reference by other MIDI manufacturers. A Windows RTP-MIDI driver[1] compatible with Windows XP through Windows 7 (32bit and 64bit) has been released, the Dutch company Kiss-Box has produced a Windows XP RTP-MIDI driver for their own devices, and a Linux implementation is under development by the Grame association. It is probable that Apple's implementation will become the "de facto" standard, and could even become the MMA reference implementation.

Alternate Tunings

Instruments that receive MIDI conventionally use the 12-pitch per octave equal temperament tuning system, which renders music that depends on a different intonation system inaccessible. The MMA addressed this issue with the 1992 ratification of the MIDI Tuning Standard, or MTS. MIDI instruments that support MTS can be tuned in any way desired, through the use of a MIDI Non-Real Time System Exclusive message.

MTS specifies a pitch in logarithmic form through a three byte message which can be thought of as a three-digit number in base 128. The byte values necessary to encode a given frequency in hertz are determined by the following formula:

p=69+12×log2(f440)

For a note in A440 equal temperament, this formula delivers the standard MIDI note number. Other frequencies fill the space evenly.

Support for MTS is not particularly widespread in commercial hardware instruments. Programs that support MTS include the free software programs TiMidity and Scala, as well as other microtuners.

Other applications of MIDI

MIDI is also used every day as a control protocol in applications other than music, including:

Non-musical applications of MIDI are possible because any device built with a standard MIDI Out connector should in theory be able to control any other device with a MIDI In port, as long as the developers of both devices agree on the meaning of the MIDI messages the sending device emits. This agreement can come either because both follow the published MIDI specifications, or in the case of non-standard functionality, because the message meanings are agreed upon by the two manufacturers.

MIDI controllers

The term "MIDI controller" is used in two different ways. A MIDI controller can be defined as hardware or software that is able to transmit MIDI messages via a MIDI Out connector to other devices with MIDI In connectors. In the other, more technical sense, a MIDI controller is a parameter that can be controlled remotely through MIDI Control Change messages. For example, synthesizers commonly use controller number 74 to control a low-pass filter's frequency. If a user assigns a physical slider to transmit controller number 74, then all changes in the slider position will be transmitted as MIDI Control Change messages on controller number 74, and the synthesizer's filter frequency will change accordingly.

MIDI controllers which are hardware and software

The following are types of MIDI controller, according to definition 1 above:

  • The human interface component of a traditional instrument, redesigned as a MIDI output device. Most commonly, the keyboard controller. Such a device provides a musical keyboard, and often other actuators such as pitch bend and modulation wheels, but produces no sound on its own and is intended only to drive other MIDI devices. Percussion controllers such as the Roland Octapad fall into this class, as do guitar-like controllers such as the SynthAxe, and a variety of wind controllers.
  • Pitch-to-MIDI converters such as guitar synthesizers analyze a pitch and convert it into a MIDI signal. Several devices do this for the human voice and for monophonic instruments such as flutes.
  • Traditional instruments such as drums, pianos, and accordions that are outfitted with sensors, whose output is processed and transmitted as MIDI data.
  • Sequencers, which store and retrieve MIDI data, and then send the data to MIDI-enabled instruments in order to reproduce a performance.
  • The MIDI Show Control (MSC) protocol is an industry standard, ratified in 1991 by the MIDI Manufacturers Association, which allows all types of media control devices to work together to perform show control functions in live and recorded entertainment applications. Just as in musical MIDI, MSC does not transmit the actual show media, but instead transmits digital data containing information such as the type, timing and numbering of technical cues called during a multimedia or live theatre performance.
  • MIDI Machine Control (MMC) devices such as recording equipment, which transmit messages for synchronization of MIDI-enabled devices. For example, a recorder that has a feature to index a recording by measure and beat can be synchronized with a sequencer.

MIDI controllers in the data stream

This section uses the second definition of "MIDI controller".

Performance modifier controls such as modulation wheels, pitch bend wheels and ribbon controllers alter an instrument's state of operation, and can be used to modify sounds or other parameters of a musical device. MIDI includes messages that represent such controller events, and they can be sent in real time over MIDI connections. MIDI makes approximately 120 virtual controller numbers available for this purpose. The value data range of the MIDI Control Change message is 128 steps (0 to 127). The first 32 controller numbers are allocated an additional 7 bits of precision for a total of 14 bits, which provides a range of 0-16383, although many manufacturers do not implement this increased resolution.

Some controller functions, such as pitch bend or key pressure, are given a dedicated MIDI data range of 16,384 steps. This higher resolution makes it possible to produce the illusion of a continuously sliding pitch, as in a violin's portamento, rather than a series of zippered steps, such as a guitarist sliding fingers up the frets of the guitar's neck. Pitch bend and key velocity use different, dedicated messages, such as Polyphonic Key Pressure, Channel Pressure, or Pitch Bend Change, rather than the ordinary Control Change message. There is a disadvantage, in that the pitch wheel and/or key pressure functions of a MIDI keyboard can generate large amounts of data that can lead to a slowdown of data throughput on the MIDI connection. This can be remedied by using a sequencer to filter continuous controller data down to a limited number of messages per second, or to messages that change the controller value by a minimum amount.

The original MIDI specification included approximately 120 virtual controller numbers for real-time modifications of live instruments or their audio. MSC and MMC are two separate extensions of the original MIDI specification, and expand the MIDI protocol beyond its original intent.

See also

References