As a soloist of the choir he performed at the concert in Torino, Italy, in front of the G-7 leaders (the seven most developed countries in the world), at the special ceremony held on the occasion of signing the contract of Bulgaria's Treaty of Accession to the European Union, in Luxembourg, 2005 and in 2002 on the occasion of Pope John Paul II's visit to Bulgaria.
Daniel Spassov`s voice is heard in many documentary films, in TV arts programs that introduce Bulgaria's cultural and historical heritage, including those of the director Stiliyan Ivanov: "Vanga", "The Healer Petar Dimkov".
They give many concerts in Bulgaria and solo tours abroad – Austria, Germany, Sweden, Denmark, Czech Republic, Israel, Corsica, Switzerland.
In 2008 Spassov and Ivanov released an album with ancient Bulgarian Orthodox Church songs, titled "Thou Art Blessed, Lord".
In 2011 Daniel Spassov and Milen Ivanov along with "The Mystery of Bulgarian Voices" made recordings in BBC Radio, London.
In April, 2013, the Svetoglas Quartet made a one-month tour in Russia, performing in Yekaterinburg, Tolyatti, Perm, Vologda, and Samara.
In September, the same year, the quartet sang at the "Thracian Gold from Bulgaria – the Legends Come to Life" exhibition's opening ceremony at the State Historical Museum in Moscow.