This post explains how to easily compose music with alda-tabs, a Domain Specific Language for Guitar Players which runs in the JVM. I have developed alda-tabs as an open source project so you can download it for free in GitHub.
What is alda-tabs?
It is a Domain Specific Language for guitar players.
It is a piece of software to help guitar players to
"execute" their music notes in the JVM, compose songs and get audio feedback.
It is an extensible tool for music programming mainly
oriented to guitar players.
It is built on the top of Alda, a DSL for
music composition in the JVM, so it is compatible with both Alda and Clojure.
Why is so easy to code guitar songs with alda-tabs?
It does not require programming skills.
It does not require traditional music notation.
It is as straightforward as writing simple guitar sketches in a
notebook.
You only have to copy your tabs from the paper to a text editor and
execute alda-tabs.
How can I create complex digital music with alda-tabs?
With alda-tabs you can execute any .alda file, so you can write
your songs/programs in both Clojure, Alda and alda-tabs in the same
block of text.
It talks to the JVM, so any experimented programmer can do impossible
things :-)
It is just a layer on the top of Alda, so if you know music theory,
then you can write complex songs using music notation.
How is the alda-tabs syntax?
Note
Remember that with alda-tabs you can always use the standard
Alda syntax and Clojure code. You can learn more about both languages
later to explore the whole potential of alda-tabs. But don’t worry,
you don’t need to know more yet. Just follow this tutorial and enjoy :)
What I am gonna show you here is the easy and super simple alda-tabs
syntax:
The tab notation
The chord notation
In 10 minutes you will be able to write songs in a text editor and
listen the result in your speakers.
Tab notation
Imagine that you want to play all the strings of the guitar, one after
another:
This example is a regular guitar tab in which all the strings are played sequentially with one hand and in which there are not fingers of the other hand pressing the fret.
So the fret number would be 0 in the six positions of the sequence.
How would we write this in Alda syntax?
Don’t worry, I will explain how to do it in alda-tabs syntax bellow (see How to do it in alda-tabs?) but it is important to read this before to compare alda-tabs withAlda.
In Alda syntax we would need to know the note equivalents of each position. And in addition:
We would write the octave and the note, one after another:
guitar: o4 e o3 b o3 g o3 d o2 a o2 e
Another way would be to write the initial octave increasing/decreasing it
when needed:
guitar: o4 e/>b/g/d/<<a/e
How to do it in alda-tabs?
Remember that alda-tabs is based in the simple concept of a tab.
Basically, the notes of a guitar can be defined by numeric combinations,
a number to identify the string (from the first at the bottom to the
sixth at the top) and a fret.
To write a note in alda-tabs you only have to write ta followed by
the string number and the fret number.
With alda-tabs we can write the same sequence that we have previously
expressed in Alda. But this time we don’t need to know which note we are
playing, we only need to write the tab, the position of our finger
considering the string and the fret:
guitar: ta10 ta20 ta30 ta40 ta50 ta60
In this example, we are asking the JMV to play a guitar with the open strings 1, 2, 3, 4, 5 and 6, one after another. That is, ta10 equals string 1 and fret 0 and so on.
Take a look now of the fretboard:
If you want to play the first note C, according to the graphic displayed above, you don’t need to know the octave, you just will pick the string 2 in the fret 1: ta + 2 + 1.
guitar: ta21
You can also modify the duration of a note adding a character at the
end. For example:
guitar: ta21 ta21W ta21Q ta21D ta21H
What does it mean? If you don’t specify a duration, this will be whole
beat (W). You can also play the note during half beat (H), double (D)
and quarter (Q). Those note durations will be proportional to the tempo
of the score. For example, the following two sentences are not the same:
(tempo 100)
guitar: ta21 ta21W ta21Q ta21D ta21H
(tempo 300)
guitar: ta21 ta21W ta21Q ta21D ta21H
Play with these combinations to see the difference. For more complex
timing, check the advanced tips bellow.
Chord notation
Imagine that rather than a sequence of notes you want to play a chord. A
basic example would be playing all the open strings at the same time:
You can do this in three ways:
In Alda syntax, using the character / to play the notes at the same
time:
guitar: o4 e/>b/g/d/<<a/e
In alta-tabs syntax, using the tab notation with different voices:
In alta-tabs syntax, but using the chord notation:
guitar: (c 0 0 0 0 0 0 W)
As you can see, the chord notation is just a Clojure function c with
seven parameters, the fret of each one of the six strings and the
duration of the chord.
For example, the D chord would be
(c 2 3 2 0 x x W)
You can also use the chord notation to play single notes. For example,
the two following sequences are exactly the same:
# alta-tab syntax
ta10 ta20 ta30 ta40 ta50 ta60
# alda-tab chord syntax
(c 0 x x x x x W)
(c x 0 x x x x W)
(c x x 0 x x x W)
(c x x x 0 x x W)
(c x x x x 0 x W)
(c x x x x x 0 W)
Advanced tips
You can play tabs with specific durations, in seconds or milliseconds by
using the function t. In this case you should write the number of
the string, followed by a dot and the fret. Add the end, you should
express in String format ("") the duration you want.
Clone this repo and open the folder alda-tabs in your terminal.
Run the Alda server with alda up.
Create a simple text file, write your song using the alda-tabs
syntax and save it.
Execute ./alda-tabs.sh followed by the path of the file you want
to play.
Listen the result.
If you want to stop a song you can stop the alda server with
alda down.
Note
You can also play some scores (provided in the /examples
folder) and modify their content to explore different sounds.
Examples
Note
In this document you can both read the code and listen the output of its execution in alda-tabs. However, the provided audio file is non-stereo. The original output of alda-tabs, however, includes panning. So explore the real result executing the code/song in your own instance of alda-tabs.
Example 1: Chords and arpeggios
You can start exploring the potential of alda-tabs with chords and arpeggios
with the example #01:
