huerta.creativa

# Solfa Algorithm

Have you ever imagine how would it be to write poetry and generate music?

The Solfa Cipher is a procedure to convert text into music.This was part of an activity of the Session 4 of the Digital Alchemy Course.

Curious fact: musical cryptography is a very old technique.

## .css-123ttdf{color:black;}.css-123ttdf:hover{-webkit-text-decoration:none;text-decoration:none;}How it works?

We will be transmitting a written message within sounds. For that is needed to convert text into musical notation using:

• cipher key 🔑 :to encrypt and decrypt message. It is defined using a clef, the tonic , a mode and a rhythmic unit.
• Notes: will carry the message mapping each letter to a pitch and a duratin. It uses the following table: Where rows represent the duration of the note `{1,2,3,4}` and the columns the pitch `{Do,Re,Mi,Fa,Sol,La,Si}` So the relationships obtained from this table would be:

Each letter correspond to a tuple (duration, pitch). For example:

`T` -> `(1,Do)`

`X` -> `(2,Mi)`

`B` -> `(4,La)`

`U` -> `(3,Si)`

## Learn by doing

Let's study this method starting from an example. Suppose we wanna encrypt the following quote:

`“A sense of essence is, in essence, the essence of sense.”`

Let's split the sentence into letters:

`{ a,s, e, n, s, e, o, f, e, s, s, e, n, c, e, i, s, i, n, e, s, s, e, n, c, e, t, h, e, e, s, s, e, n, c, e, o, f, s, e, n, s, e }`

We identify letters used: `{a, s, e, n, o, f, c, i, t, h}`

And map them to a tupple (pitch, time) according the table:

`a` -> `(1,Mi)` == `E1`

`s` -> `(1,Fa)` == `F1`

`e` -> `(1,Sol)`== `G1`

`n` -> `(1,La)` == `A1`

`o` -> `(1,Si)` == `B1`

`f` -> `(4,Do)` == `C4`

`c` -> `(3,Re)` == `E3`

`t` -> `(1,Do)` == `C1`

`i` -> `(1,Re)` == `D1`

`h` -> `(3,Mi)` == `E3`

For the cipher key, we are using some default values given by:

• clef: treble
• tonic: C
• rhythym: 1/4

So, our sentence will be converted into:

`E1 F1 G1 A1 F1 G1 B1 C4 G1 F1 F1 G1 A1 D3 G1 D1 F1 D1 A1 G1 F1 F1 G1 A1 D3 G1 C1 E3 G1 G1 F1 F1 G1 A1 D3 G1 B1 C4 F1 G1 A1 F1 G1`

It looks like this (which may resemble to something more familiar to the musical world): ## Understanding musical score in detail: The tonic key used is `C Major` that's why it has no flats nor sharps.

But wait..

### WHERE ARE THE MEASURES?

Using 4/4 meter means that the length of a single measure has duration of 4 units and each units length is given by the `rhythym unit`: 1/4.

Let's see our notes again and try to figure out where bars go:

The procedure will be: counting the duration of each note until we reach 4 and then draw a bar:

`E1 F1 G1 A1 |` ➡ So we have the first measure.

Let's keep on doing it with the following 4 notes:

`F1 G1 B1` Oops~~~ we count 3 and the next (pitch, duration) is `C4` which would imply adding 4 !?! But our meter was 4.

To resolve this we keep on adding notes to he measure and`counting` durations as long as the `counter` is less than 4.

If not we fill the rest of the available units with silences completing the measure. And restart counter for next note.

`F1 G1 B1 *Z1* | C4 |`

And here it how it looks like. 