HOW DOES MIDI MAKE MUSIC?
情况怎样米迪作音乐?
If MIDI was just another way of sending information from one computer-based device to another, you wouldn't be reading about it in Keyboard. What makes MIDI special is that the information that travels along a MIDI cable relates specifically to music performance.
如果米迪是仅仅另一从一基于电脑的装置把信息寄给另一个的方式,你将不在键盘中读到它.什么作米迪特刊是沿着一条米迪缆绳移动的信息特别和音乐表现关联.
To begin with, MIDI defines note-on and note-off messages. When you press a key on a MIDI keyboard, the keyboard transmits a note-on message. This tells any MIDI device that happens to be listening that a new note has begun. When you lift the key, the keyboard sends a note-off message. This tells any receiving device that it's time to stop playing that particular note. One of the most basic concepts in MIDI is this: The note-on message says nothing about the actual sound of the note. It only says, "Start a note now." The sound depends entirely on the receiving module. If it's set up to make a piano-type sound, the note-on message will cause a piano note to sound. If the receiving module is set to play saxophone, the exact same note-on message will generate a sax note.
首先,米迪确定记录向前和离开信息笔记当你按在一个米迪键盘上键的时候,键盘传送一关于信息的笔记.这个说任何恰好听的一新笔记已开始米迪装置. 当你提高音调的时候,键盘寄送一离开信息笔记.这个告诉任何接待装置现在是停止玩那特殊笔记的时候了.在米迪中最基本概念之一是这个: 关于信息的笔记谈到重要的真实声音说没有什么.仅它说现在发动一笔记.声音完全取决于接待模数.如果它的设置将造成一轻的给声音的便条, 作一轻的类型声音,关于信息的笔记.如果接待模数准备好玩萨克斯管,精确同一关于信息的笔记将产生一石板斧笔记.
A single note-on message has three parts. The first part, called the status byte, defines what type of message it is - in this case, that it's a note-on message, and that it is on, let's say, MIDI channel 3. (For more on channels, see below.) The second part of the note-on message is the note number. In other words, which key is being played? In theory, a MIDI keyboard can be 128 notes wide, because 128 note numbers are available. A typical five-octave MIDI keyboard uses the notes between 36 and 96. (Middle C is note 60.) The third part of the note-on message is the velocity. This number, which can be anywhere from 1 to 127, tells how fast the key was travelling as it moved from its starting position down toward the keybed. Normally, a synthesizer will respond to a higher velocity by making the note louder or brighter.
一单一的关于信息的笔记有四分之三.状况字节称为第一部分定义什么样的类型的信息它是在这个情况中,它是一关于信息的笔记和它是在米迪上, 比如疏导3.(为在渠道上更多,请参阅下文).第二部分关于信息的笔记是笔记号.换句话说哪一个把钥匙被玩?在理论中,因为128笔记号是可用, 一个米迪键盘能很开是128笔记.一个典型五八度米迪键盘使用笔记在中间36和96.(中央C是笔记60).关于信息的笔记的三分之一是速度.这能是的数任何地方从1 到127说出怎样快钥匙当它不它的向下朝着keybed开始位置移动时,移动.在一般情况下,一位综合者将以做笔记更很响更或者更明亮对一更高速度作出反应.
A note-off message has the same three parts - the status byte, the note number, and the velocity. The note-off velocity (which is more often called release velocity) can be different than the note-on velocity. But only a few MIDI keyboards can sense the velocity with which a key rises from the keybed, and only a few MIDI synths can alter their sound based on the release velocity value that they receive. Most MIDI keyboards transmit a fixed release velocity of 64, no matter how quickly or slowly you lift the key.
一离开信息笔记有同样的四分之三-状况字节,笔记号和速度.离开(是更多常常称为发行速度的)速度笔记能是和关于速度的笔记不同.但是仅几米迪键盘能感觉到随着一把钥匙升起的速度从k eybed和仅几米迪synths能改变,把他们的语气建立在他们收到的发行速度价值的基础上.无论怎样迅速或者缓慢你提高音调,绝大部分米迪键盘传送一6 4的固定的发行速度.
By the way, a MIDI note-on message with a velocity of zero works the same as a note-off message. It turns the note off rather than turning it on. This message is used for technical reasons that we aren't going to try to explain here. For the most part, you shouldn't need to worry about it. All that matters in most musical situations is the obvious: When you press a key, a note starts. When you lift the key, the note stops. MIDI defines a number of other musically useful performance messages. Some are used quite a lot, and some more rarely. Here are the types you'll run into most often:
顺便说一件事,一米迪关于随着一零的速度信息的笔记作为一离开信息笔记引起同样的.它翻转离开而不是打开它笔记.这信息为技术我们将不设法这里说明的理由被使用. 大部分,你不应该需要担心它.在最音乐处境中那一切物质是显而易见当你按键的时候,一笔记启动.当你提高音调的时候,笔记停止.米迪定义许多其它声音悦耳地有用表现信息. 一些很多和再多一点很少被使用.这里是你将最常常让注入的类型:
Pitch-bend messages are usually transmitted by the pitch wheel, lever, or joystick. The message itself says nothing about the actual depth of the pitch-bend as a musical interval. The receiving synth might be set to bend up and down by a maximum of an octave, a major second, or by some other interval. The pitch-bend message contains information only about the position of the wheel or equivalent hardware. If the wheel is moved halfway from its center position to the top of its travel, the pitch will move halfway from the starting pitch of the note to the maximum bend interval.
通常调子轮子,杆或者操纵杆传达调子转弯处消息.信息它自己谈到是一音乐时间间隔调子转弯处的真实深度说没有什么.音响合成器可以准备好来来回回弯曲经过一最大限度的一八度, 一主要秒或者按照一些另一时间间隔的接待.调子转弯处信息含有仅关于轮子或者等于硬件的位置的信息.如果轮子从它的中心位置去它的旅行的顶部半截子被移动, 调子将半截子从重要的开始调子迁移到最大转弯处时间间隔.
Program change messages are usually transmitted by pressing the program change buttons on the front panel of the synth. They tell the receiving module to switch to a new program (also called a patch, sound, voice, or preset) within its stored memory bank. But again, what exactly the program will sound like is not determined by the MIDI message. A MIDI program change message is in two parts. The status byte says, "Program change, channel XX" (that is, some channel number between 1 and 16), and the second byte, which is called a data byte, gives a program number between 1 and 128. The receiving module will switch to whatever program it happens to have stored in the memory location that corresponds to that number.
通常通过按程序改变在前部音响合成器的镶板上电钮传达程序改变消息.他们告诉接待模数转换到,也或者在它的储藏存储体以内预先准备一新程序认为是一补丁, 声音,声音.但是再次,准确程序将听起来像什么不按照米迪信息决心.一米迪程序改变信息是二在一定程度上.状况字节说"为改变编制程序, 疏导XX"(也就是说疏导数在中间1和16),和一数据字节被给打电话第二字节给出一程序号在中间1和128.接待模数将在与那数相符的记忆位置中转换到它恰好已储藏不管什么程序.
The new General MIDI specification changes this picture a bit. Modules that are General MIDI compatible will have specific types of programs stored in specific numbered memory locations. This allows you to call up, say, program 17 and have some confidence that it will do the job musically, because program 17 will always be a drawbar organ sound on any General MIDI synth. But the basic principle is still true. The transmitting synth has no idea whether the receiving synth is a General MIDI instrument or not. There is no such thing as a "General MIDI program change" that exists as a separate type of MIDI message. The program change message is always the same, but if the receiving synth is one you haven't worked with before, sending program changes will give you more musically predictable results if it's General MIDI compatible than if it's not.
新普遍米迪规格说明一点儿改变这图片.是普遍米迪兼容的模数将有被在特有给编号记忆位置中储藏特有类型的程序.这个允许你比如说打电话, 为17编制程序和让一些信心普遍,因为程序17将总是是一牵引杆器官声音,它有关略将声音悦耳地做工作的米迪音响合成器.但是基本原理仍然是真实的. 不管接待音响合成器是一件普遍米迪工具与否播送信号音响合成器没有观念事实上没有像一"普遍米迪程序改变"这样的东西,其是一独立类型的米迪信息存在的. 程序改变信息总是也一样,如果它是普遍米迪兼容,但是如果接待音响合成器你还没有随着以前负责的是一回事,寄送程序改变将给你更声音悦耳地更可预言的结果与相比如果它不有.
As with most of the messages we're looking at, there are wrinkles in the area of program changes that we're not going to try to deal with this month - things like, what happens if a synth only stores 64 programs in its memory, and you send it program change 103? It might ignore the program change, it might switch to program 39 (because 103 - 64 = 39), or it might do something else.
和信息的绝大部分一样,在我们不要,去设法处理这个月是的程序改变的区域中有皱纹-如果一台仅音响合成器以纪念它储藏64程序,和你给它寄送程序改变1 03,东西喜欢什么发生我们考虑吗?它可以忽视程序改变,(因为103-64=39)或者它可以做别的什么,它可以转换到程序39.
Pressure messages are used to alter the sound of notes while the notes are sustaining. Pressure comes in two flavors. Channel pressure messages have an identical effect on all of the notes that are sustaining, while the key pressure (also called polyphonic pressure) value can be different for each note in a chord. Pressure is also called aftertouch.
在笔记是的同时,使用压力信息改变重要的语气支撑.压力在二味道中来.在也认为重要压力是多音的压力价值能对于每一在一和弦中笔记是不同的同时, 渠道压力信息对全部的是的笔记有影响完全相同支撑.压力是也称为aftertouch.
Continuous controller messages make other kinds of changes in sustaining notes. MIDI has room for more than 100 continuous controllers to operate on each channel, but very few synths can respond to this many at any given time. The continuous controllers are numbered. Some of the numbers have well-defined meanings, while others are left undefined so that each instrument can use them in its own musical ways. The most commonly used continuous controllers are controller 1, which is the modulation wheel, controller 64, which is the sustain pedal, and controller 7, which controls the overall volume of an instrument.
连续审计员信息作其它种类的支撑笔记的改变.米迪有超过100个连续审计员可用的空间要运作在每一渠道上,但是非常很少一点synths能对这个反应良好给在一些很多时间. 给连续审计员编号.在其他的是留下未下定义的,因此每一工具能在它的自己音乐方式中使用他们的同时,某些数有非常明确意思.最通常用过的连续审计员是审计员1 ,其是是的调节轮子,审计员64的支撑踏板和审计员7,其控制一件工具的总数量的.
These messages are all called channel messages. If you read last month's column, you'll remember that MIDI defines 16 channels. All of the notes, pitch-bends, program changes, and other messages we've been talking about are tagged with a channel number between 1 and 16. If the tone module on the other end of the cable is set up to receive on the same channel that the message is on, then it will respond by doing whatever the message tells it to - assuming that it's also capable of responding to that type of message. Many modules ignore polyphonic aftertouch, for instance. If the message is on the wrong channel - a channel that the module is not set up to respond to - the message will also be ignored.
这些信息是所有的称为渠道信息.如果你读上个月专栏,你将记得米迪规定16条途径.我们一直在谈全部的笔记,调子转弯处,程序改变和其它信息被加上一渠道号在中间1 和16的标签.如果另一缆绳的把音调模数竖起来向上在同样的渠道上收到那个,信息在继续,然后它将以做信息告诉任何东西它回答-也假定那个是能对那类型的信息反应良好. 很多模数例如忽视多音的aftertouch.如果信息是在错误途径-一条渠道上模数不去被建立回答,信息将也被忽视.
One other big issue that we should at least mention is timing. In order to be musically usable, MIDI has to be able to transmit note-ons, note-offs, and other messages very quickly. (If you played a note and heard it half a second later, you wouldn't like it.) Without going into a lot of technical detail, we can say that as a rule of thumb, a MIDI note-on requires about 1 millisecond (that's one thousandth of a second) to be transmitted. And MIDI messages are sent down the cable one at a time. So if you want to transmit a 20-note chord over MIDI, it takes about 20 milliseconds (1/50 of a second). If you think of a chord as a group of notes that all start at exactly the same moment, then MIDI can't transmit chords at all. Those 20 notes are sent one after another, as a very, very fast arpeggio.
我们应该至少提到的一另一大问题打拍子.为了声音悦耳地是可用,米迪必须能非常迅速传送笔记ons,笔记offs和其它信息.(如果以后半秒, 你玩一笔记和听它,你将不喜欢它).一米迪指出不进入许多技术细节,我们能拇指的通常说那个向前要求是一会儿被传送的一第一千的大约1 毫秒.和一次一个使米迪信息下降缆绳.那样如果你想要在米迪的上方传送一20笔记和弦,它大约20毫秒一会儿的1/50发生作用.如果你想一想一作为一群笔记和弦, 同样的时刻,所有的在旁准确出发的,然后米迪能根本不传送和弦.那些20笔记是一非常,非常快琶音一个接一个寄送
We'll have much more to say about timing in another column. For now, what's most important to understand is this: It's possible to clog up the MIDI data stream with so many pressure and continuous controller messages that the timing of the notes gets pushed around, resulting in a loose, sloppy-sounding performance. But this doesn't happen as often as you might expect. Most of the timing problems that you'll hear with MIDI instruments are due to the receiving synth responding too slowly ? for example, taking 20 or 30 milliseconds after the MIDI message has arrived to switch on a single note. You won't hear nearly as much time slop with newer instruments as with older ones. If youve only got two hands, there's a limit to how much you can do with MIDI in a live performance. We'll cover that another time, when we ask, What is a sequencer?
我们将有多得多,谈到在另一柱中定时说.暂时,什么是最重要懂得是这个:用如此多压力和连续审计员信息堵塞米迪数据溪流,重要的定时使变得时间紧迫四周结果是一松, 马虎发声的是可能的表现.但是这个不尽管多次发生你可以期待.定时问题你将用米迪工具听见的绝大部分是由于太缓慢回答接待音响合成器吗? 例如,20或者30毫秒像米迪信息已到来打开一单一的笔记.你将不几乎听同样多有更新工具的和更老那些一样时间积水.如果仅youve得到二只人手, 一你能用在一活表现中米迪做多少是有限的.另一我们问什么是一程序装置的时间我们将包括那个吗?
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