/*pictures comming soon*/
In later 1960’s Lluís Callejo Creus (1930-1987) was working as technical director in the experimental nuclear reactor ARGOS sited in the UPC University.
During the nuclear manouvers he realized about pretty time-randomized clicks, sounding from inside the reactor… Lluís Callejo, musician in spirit, perceived it as beautiful abstract music.
Later on, Callejo meet J.M Mestres Quadreny (1929-2021) in a concert of Quadreny, 
and after he went to talk to him because he found a big similarity between random Quadreny’s music and the reactor’s sounds.
JM.Mestres was really interested in random calculations to generate
random music and visited the UPC university computing lab with Callejo, to take some random sequences and generate music with it.
Then,Lluís Callejo, who had advanced knowledge in analog and digital electronics, proposed creating a machine to make random sounds and make it controllable by its interface, affecting the qualities of the sequences and sound, such as the speed of the notes, the duration of the notes, the heights, the pitch range, etc. .
At this time, early 1970’s, they met Andrés Lewin Righter 
who came from Columbia Princeton Electronic Music Center, as professor and electronic music composer, and togheter they founded Phonos, as an electroacoustic music laboratory in Barcelona.
Callejo contributed to Phonos by creating the Stokos 4 synthesizer, based on the ideas of Mestres Quareny and Callejo about the generation of random music.
Callejo spent his time researching and developing this machine, and at the end he managed to make a random monster. Its high complexity and abstract results were not easy to perceive as music, but most or the times it sounded fun and musical with a random taste…
When someone played it, most of the time, they had the feeling of not knowing what was being controlled, as if they were unfamiliar with synthesizers, as someone taking a modular for the first time.
But with a little training, the player was able to create sound atmospheres, quite random melodies…
During the 1980s, Phonos began to grow as a group that accepted new additions such as Gabriel Brnčić, J.M. Berenguer, E. Polonio, O. Graus, Anna Bofill, Montserrat Capdevila J. Nuix, Jordi Rossinyol, etc … and began to have a presence in the world of contemporany music, participating in festivals such as…
//need to put here more festival names//
Angouleme Biennal, Venezzia Bienalle, IRCAM… etc
And also organizing their own cycles of concerts, either at the Fundació Miró or at the Palau de la Música Catalana, in Barcelona.
On most of those sessions, they used to put Stokos4 sounding during the breaks, giving a special modern abstract ambiance to the auditorium’s conversations.
The avant-garde feeling of research and creation was present in everything that was done there and marked new lines within the international contemporany electroacoustic music scene.
In 1987 Lluís Callejo died of cancer and left numerous projects and pieces of music uncompleted.
He left behind many teachings in electronics, digital synthesis, and computational composition, to students of Phonos, and some musical pieces of electroacoustics and contemporany research.
During many years, Stokos4 remained stored on Phonos decks and began to be damaged by time and no maintenance.
Lately, Phonos’ team decided to transfer Stokos4 to the Barcelona Music Museum, giving it a new home to preserve, study and exhibit in the museum’s gallery.
For more than ten years, Stokos 4 remained in the museum’s showcase, and its electronic circuits began to be severely damaged by time.
In 2013-14, Phonos and Museu de la Música de Barcelona, prepared
a 40-year exhibition of Phonos’ history and tried to fix and preserve Stokos4, but after being analyzed by Karlos Pizarro (a very good synthesizer repairer), he said it was so risky to repair it because it could be more damaged, due to Its artisanal and too complex construction.
At the same time, Albert Callejo, Lluís Callejo’s second son, took the ideas, the plans and started his virtual Stokos4 project. Making an accurate 3D model and simulating the sound engine with PureData
Finally, it was a rough emulation because it was impossible to recreate it exactly, but it was exposed and sounding to users, throughout 2014 in the museum, near to the old machine.
Today, September 2021 with some improvements, Virtual Stokos4 keeps alive the idea of Lluís Callejo’s machine and you can get it from Google Play Store.
