Midi Numbers

[Jenni Israelsen]

Notenames, MIDI numbers and frequencies are related here in tables and via an application that converts them. The musical interval between two notes depends on the ratio of their frequencies. See Frequency and Pitch for more details and an introduction to frequency and pitch.

An octave is a ratio of 2:1 and, in equal temperament, an octave comprises 12 equal semitones. Each semitone therefore has a ratio of 21/12 (approximately 1.059). By convention, A4 is often set at 440 Hz. These data were used to calculate the first table below, which gives the frequency of any standard keyboard note or MIDI note number. To convert from any frequency to pitch (i.e. to the nearest note and how far it is out of tune), go to the frequency to note converter.

In electronic music, pitch is often given by MIDI number: let's call it m for our purposes. m for the note A4 is 69 and increases by one for each equal tempered semitone, so this gives us a simple conversion between frequencies and MIDI numbers (again using 440 Hz as the pitch of A4):

The MIDI note numbers 0 to 127 map to musical notes as shown in the following tables.Note that although most manufacturers label this range as C-2 to G8, with middle C beingC3 (as I have here), you may come across some manuals that describe this range as C-1 toG9 (with middle C being C4).

Hi, I am sorry if this question has been asked before but when I searched the forum I could not find the answer. I have also searched my Logic Pro X documentation and if the answer is in there, I'm sorry but I could not find it. This has to be a simple problem to solve but it's hurting my brain...

On every single MIDI device I have, there is exactly an octave difference between the note message that the device is sending and the note message received by Logic Pro X. For example... on my Akai MPD218 drum machine, pad #1 is set (on the device) to transmit B1 (B one) but Logic Pro X "reads" the incoming MIDI message as B0 (B zero).

The option I've opted for is to change the notes in the midi keyboard editor app (Alesis VI Editor), setting them all one octave up, and in Logic Pro now it shows the correct note for me (although it should show an octave upper, according to the note number)

I'm sure that there's more elegant way to convert numbers to symbols. But, that's how the newbies do. In the patch, there are several, instead of one [sel] object, I did it that way because I found it impossible to wire it's outputs when they are so close together. Any suggestion is welcome.

sinewave

thank you, slur!

I must admit that I don't understand your explanation. I even cannot find anything about message generation in the help file. Will you, please, attach a patch with the example?

Thank you very much!

sinewave.

I want to create an array that will assign the MIDI note numbers to their corresponding letter, so I can display the note letter on the LCD, instead of the number. Any ideas on how to write this array? I believe it may be quite simple but I wouldn't know the logic to do it.

Any help is appreciated.

This assumes that the lowest note number you see is 60. If there are lower numbers, replace 60 with the lowest number, and make sure that the notes array defines the strings in order starting at that lowest value.

I guess they don't repeat at all in theory. Across the 128 notes, You have about 10 octaves, so example, there will be 10 C's, but I wanted to display C5/C4/C3 depending on which C note it is, instead of just C.

So I guess I need to enter from C0-G10.

They better release this until i start profiling the Mesa 4 x 12 tomorrow. The actual fireware fucked up about a third of all the profiles i made with a horrible distorted tone and feedback. I cant really see what might cause this problem, it just seems to happen sometimes...

I get this "E" while trying to switch the delay mix on and off. With my Gordius Little Giant I have the possibility to send

two message streams. The 1st one with 1st step on the switch and 2nd one with (guess what?) the 2nd step (like an on/off switch)

Data sent is 1st CC#27 value 1 and 2nd CC#27 value 0. This is what happens:

- 1st time hitting the switch nothing happens

- 2nd time nothing happens with the stomp and the "E" appears

- 3rd time delay stomp turns on

- 4th time delay turns off and the "E" persists

I'm a midiot and do not know how to set up a Line6 X3 floorboard to control the KPa. The Volume pedal works and program change up/down work. Do I just need to go into the X3 and tell it which cc commands are assigned to each IA?

The original MIDI standard was later augmented to include the Standard MIDI File (SMF) specification, which describes how MIDI data should be stored on a computer. In the following, we denote SMF files simply as MIDI filesor MIDI representations. The SMF file format allows users to exchange MIDI data regardless of the computer operating system and has provided a basis for an efficient internet-wide distribution of music data, including numerous websites devoted to the sale and exchange of music. A MIDI file contains a list of MIDI messages together with timestamps, which are required to determine the timing of the messages. Further information (called meta messages) is relevant to software that processes MIDI files.

The most important MIDI messages are the note-on and the note-off commands, which correspond to the start and the end of a note, respectively. Each note-on and note-off message is, among others, equipped with a MIDI note number, a value for the key velocity, a channel specification, as well as a timestamp. The MIDI note number is an integer between $0$ and $127$ and encodes a note's pitch, where MIDI pitches are based on the equal-tempered scale. Similarly to an acoustic piano, where the $88$ keys of the keyboard correspond to the musical pitches A0 to C8, the MIDI note numbers encode, in increasing order, the musical pitches C0 to G$^\sharp$9. For example, the concert pitch A4 has the MIDI note number $69$.

The following figure shows various symbolic music representations of the first twelve notes of Beethoven's Fifth including a sheet music representation, a MIDI representation (in a simplified, tabular form), and a piano-roll representation.

An important feature of the MIDI format is that it can handle musical as well as physical onset times and note durations. Similarly to sheet music representations, MIDI can express timing information in terms of musical entities rather than using absolute time units such as microseconds. To this end, MIDI subdivides a quarter note into basic time units referred to as clock pulses or ticks. The number of pulses per quarter note (PPQN) is to be specified at the beginning, in the so-called header of a MIDI file, and refers to all subsequent MIDI messages. A common value is 120 PPQN, which determines the resolution of the time stamps associated to note events.

Like the sheet music representation, MIDI also allows for encoding and storing absolute timing information, however, at a much finer resolution level and in a more flexible way. To this end, one can include additional tempo messages that specify the number of microseconds per quarter note. From the tempo message, one can compute the absolute duration of a tick. For example, having 600000 $\mu$s per quarter note and 120, each tick corresponds to 5000 $\mu$s. Furthermore, one can derive from the tempo message the number of quarter notes played in a minute, which yields the tempo measured in beats per minute (BPM). For example, the 600000 $\mu$s per quarter note correspond to 100 BPM. While the number of pulses per quarter note is fixed throughout a MIDI file, the absolute tempo information may be changed by inserting a tempo message between any two note-on or other MIDI messages. This makes it possible to account not only for global tempo information but also for local tempo changes such as accelerandi, ritardandi, or fermate.

The file format specifications for MIDI are complex and go beyond the scope of the FMP notebooks. The good news is that there are various software tools for parsing, manipulating, synthesizing, and storing MIDI files. In the following, we introduce the Python package PrettyMIDI for reading MIDI files. Furthermore, this package transforms the (often cryptic) MIDI messages into a list of easy-to-understand note events. The following code cell parses a MIDI file, converts the data into a standard Python list, and displays the first MIDI events in a table. We continue with our Beethoven example from above.

Finally, we plot the MIDI data in a piano roll representation, where the color (given as RGBA value) of each rectangle is determined by a note's instrument (RBG value) and velocity (alpha parameter, opacity). We now use a visualization function from libfmp that has been introduced in the notebook on our CSV format for symbolic music.

The next example reads and visualizes a MIDI file for the beginning of the four-voice Fugue BWV 846 in C major by Johann Sebastian Bach. In the MIDI file, the four voices (soprano, alto, tenor, basso) are encoded by four different MIDI channels.

We can convert a list of note events into a CSV file with the to_csv method of a pd.DataFrame. In the following code cell, we convert a MIDI file into a CSV file as used in the FMP notebook on the CSV format.

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