This CD is one of the 5 CDs where old spanish music is explored. On the first four CD Atrium Musicae is involved under the direction of Gregorio Paniagua (the brother of Eduardo Paniagua)
his album with the works of the Codex Calixtinus (based on the version used in Silos) and the Antofonaria Mozarabe, the producer Roborto Pla uses the Cantor of Silos and they are singing full of devotion and it does not sound heavy. The Antifonria Mozarabe is absolutely wonderful and unique. Although the various elements (5 pieces) are sounding a bit repetitive, because they have similarities.
The brother Eduardo Pnaigue became very famous because he later produced and recorded all the Cantigas de Santa Maria, (and they are wonderful ) but also he recorded more Visigotic-Mozarabe pieces, which you find on one of my posts; He also uses a light voice for singing these wonderful pieces.