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what is midi?

#3
And, as applied to a MIDI'd bass or ERB, it would refer to having some system installed that will, by some means, put out MIDI note messages (as a minumum), corresponding to the notes you play, over a MIDI jack/cable. These MIDI note messages are then used by the receiving device, e.g. a synth module making corresponding sounds, or a software sequencer on a computer recording the notes played.
 
#6
jordan_frerichs said:
What is midi? keep hearing it. n idea what it means
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In the late 70's early 80's the electronic instrument manufacturers agreed on a standard for their instruments to communicate with each other:

Music Instrument Digital Interface (M I D I)

Midi has nothing with audio to do, instead the system is kind of like an electronic virtual note information translator. When you press a certain not, midi starts a serial flow of data saying "The note xx was now played" and when you stop playing the note midi registers "The note xx was now released".

Then midi registers a lot of other data as well, such as velocity, pitch changes and other modulators.

It's amazing that it's still around as it is a serial interface/protocol and with todays measurements, pretty slow.

Hope that breaks it for ya, if not, hit me back!

Cheers!

D.Don
 
#7
and well to explain what the 'protocol' is, its binary language, the language used in any digital device. It consists of 1s and 0s... the good thing is a distorted 1 or 0 is still a 1 or a 0. Then you have the bit depth, 16 bits means 65 000 different possiblities... e.g. 1000 0000 0000 0000 is one possibility, 1100 0000 0000 0000 is another. 24bits is something like 16 million possibilities. Its quite complex and simple at the same time. Any instrument that uses Midi is considered as a controller, so if you have midi on a bass or a guitar you can hook it up to any synth that has a Midi input and control it from the bass or guitar. It goes to the point where you can control entire light shows with a controller, you can do pyrotecniques, whatever with midi. fyi, midi means musical instrument digital interface. hth jordan, peace.
 
#8
D.Don said:
It's amazing that it's still around as it is a serial interface/protocol and with todays measurements, pretty slow.D.Don
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whats changed is the bit depth however, or unless im mistaken, Midi has always been 127 values, therefor being only 8 bits. remember the NES was 8 bit.... SNES was 16... but I think the bit depth has more to do with digital audio recording.
 
#10
T2W said:
whats changed is the bit depth however, or unless im mistaken, Midi has always been 127 values, therefor being only 8 bits. remember the NES was 8 bit.... SNES was 16... but I think the bit depth has more to do with digital audio recording.
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?

Are you talking about the not yet finished midi 2.0 standard?

Midi 1.0, the current standard, will most probably always be 8 bits as there's like thousands of machines out there who would become quite confused it the data changed format all of a sudden...

Digital audio recording???

D.Don
 
#11
T2W said:
and well to explain what the 'protocol' is, its binary language, the language used in any digital device. It consists of 1s and 0s... the good thing is a distorted 1 or 0 is still a 1 or a 0. Then you have the bit depth, 16 bits means 65 000 different possiblities... e.g. 1000 0000 0000 0000 is one possibility, 1100 0000 0000 0000 is another. 24bits is something like 16 million possibilities. I
...
Click to expand...

T2W said:
whats changed is the bit depth however, or unless im mistaken, Midi has always been 127 values, therefor being only 8 bits. remember the NES was 8 bit.... SNES was 16... but I think the bit depth has more to do with digital audio recording.
Click to expand...
Mario, I think you may be adding to some of the confusion that some people may have.

Bit depth does not enter into MIDI in the way that you are suggesting up until the end of your last post. You are talking about the encoding resolution of audio signals, where the higher the number of bits, the higher the resolution, and the more accurate the audio; and also the more bandwidth it uses.

As was previously stated, MIDI is not sending audio information! It is sending information about the notes. These messages are in a fixed format, no resolution involved. Some typical MIDI messages might be "channel 02:note 34 on:velocity 56", "channel 02:note 39 on:velocity 52", "channel 02:note 56 off", "channel 02:pitch bend:+02","channel 02:pitch bend:00", et cetera.

There are plenty of other messages also, but they are mostly commands, also with some status reporting, timing signals, and such, but not audio information. The 127 referred to is not a bit depth, rather it is the number of MIDI notes defined, which has served well in a world where a standard piano has only 88 notes.

On a typical synth module, which has not been set in an 8va or 8vb mode, a received command of "note 60 on" will begin to sound a middle C (also variously known as C4, c', or key #40 on a piano) in whatever voice the synth is set for. A command of "note 60 off" will make a middle C stop playing, if there was one already playing, or will have no effect if none was playing.


BTW MIDI uses 10-bit bytes, not the computer-typical 8-bit bytes. But again that is its data structure; it pretty irrelevant to the content of messages carried.

Similar to USB or FireWire, MIDI defines both the hardware (cable standard, plugs and jacks, voltages, pinouts and grounding scheme, and opto-isolators at both ends) and the communication protocol (the allowable messages, and the format they take).


To sum up, and to clarify the mess I just wrote above: MIDI does not send audio information. It sends performance information.
 
#12
pilotjones said:
To sum up, and to clarify the mess I just wrote above: MIDI does not send audio information. It sends performance information.
Click to expand...

And it may be old fashioned serial and slow by today's data transmission standards, but it's still faster than anyone can wiggle their fingers across a keyboard or other controller, and it's still fast enough to keep up with sequencers, way beyond what would be considered musical.

So, it's still 'fit for purpose'.

Couple that with the fact that there are still millions of people with a big investment in Midi devices and even more investment in songs created in sequencers, DAW's and the like and it's clear that replacing it is not a straightforward task.
 
#14
T2W said:
right, my bad. Thanks for the correction. I was mixing up bit depth in audio recording and the 127 possible commands in Midi. Both still use binary code though... right?
Click to expand...
Yeah, it's binary, as I said arranged into 10-bit bytes.

To be more exact, there are some large number of commands in MIDI. Two of those commands are note-on and note-off, and for those particular commands, the note number value can be 0~127, and the velocity value can be either 0~127 or 1~127 (IIRC). Other commands are structured differently, and can have different ranges/number of bits. For example, IIRC, pitch bend has 256 values, which are interpreted as -127~+128.
 

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