One of the most significant enclosures in worship spaces is that of the choir. Generally,
from a historical point of view, the choir is a semi-enclosed and privileged area reserved for the
clergy, whose position and configuration gives it a private character. Regarding the generation and
transformation of ecclesial interior spaces, the choir commands a role of the first magnitude. Its shape
and location produce, on occasions, major modifications that significantly affect the acoustics of these
indoor spaces. In the case of Spanish cathedrals, whose design responds to the so-called “Spanish
type”, the central position of the choir, enclosed by high stonework walls on three of its sides and
with numerous wooden stalls inside, breaks up the space in the main nave, thereby generating other
new spaces, such as the trascoro. The aim of this work was to analyse the acoustic evolution of the
choir as one of the main elements that configure the sound space of Spanish cathedrals. By means of
in situ measurements and simulation models, the main acoustic parameters were evaluated, both
in their current state and in their original configurations that have since disappeared. This analysis
enabled the various acoustic conditions existing between the choir itself and the area of the faithful
to be verified, and the significant improvement of the acoustic quality in the choir space to become
apparent. The effect on the acoustic parameters is highly significant, with slight differences in the
choir, where the values are appropriate for Gregorian chants, and suitable intelligibility of sung text.
High values are also obtained in the area of the faithful, which lacked specific acoustic requirements
at the time of construction