The first prize winner at Georgia Tech Margaret Guthman Musical Instrument Competition in 2014, Tolgahan Çoğulu, designed his "Adjustable Microtonal Guitar" in 2008.
His first CD with microtonal guitar, Atlas, was published in 2012 by Kalan Music. His microtonal and fretless guitar duo and lecture recital, ‘Microtonal Guitar Music,’ has taken him to many festivals and universities in 33 countries. Tolgahan is building a repertoire for microtonal guitar with more than forty composers involved at this point. In 2013, he became an Associate Professor in Guitar at Istanbul Technical University’s Turkish Music State Conservatory, where he had founded the classical guitar department in 2010 and the world’s first microtonal guitar department in 2014. His second CD ‘Microtonal Guitar Duo’ has been published by Kalan Music in June 2015. His recording of William Allaudin Mathieu’s three-movement ‘Lattice-İşi’ in just intonation was published in the US in 2016. He completed a research project entitled ‘Historical Tunings on Microtonal Guitar’ at the University of Bristol in 2016. Between 2015-2017 he collaborated with the University of Music Würzburg for the project ‘Creating and Presenting a Repertoire for the Microtonal Guitar’ supported by DAAD in which 12 composers wrote pieces for microtonal guitar and ensemble. His book ‘Microtonal Guitar’ was published in 2018 by Mojo Roots Music, co-authored by Fernando Perez. Currently he is teaching at Istanbul Technical University.