Mallorca Cathedral rebuilds Gaudí’s lost voice cone in 3D

A vanished voice-amplifying canopy from Mallorca Cathedral’s main pulpit has returned as a 3D model. Researchers at Universitat Rovira i Virgili rebuilt Antoni Gaudí’s tornavoz — a wooden and fabric structure designed to strengthen and direct a speaker’s voice — in Palma on 26 August. The original was demolished in November 1970.

Gaudí designed the canopy for the octagonal main pulpit as part of a 1901 commission from Bishop Pere Joan Campins to restore and reshape liturgical features in the cathedral. Its three curved, parabolic surfaces were intended to focus sound towards a particular area in front of the pulpit.

The lost piece had been declared a Historic Monument. Architect Le Corbusier had also championed it, sketching it in his travel notebook during a 1932 visit to Mallorca.

Ten photographs fill the gaps

No plans or detailed geometric records of the tornavoz survived. The team therefore built a digital model of the cathedral and pulpit using laser scanning and photogrammetry, then worked from ten historic photographs.

They made 1,250 scans of the cathedral, producing a cloud of about 21 million points. The main pulpit was modelled in 3D with 95 per cent accuracy.

For each old photograph, the researchers calculated the camera position using two different geometric methods. They selected five images where the difference between those calculations was less than one metre.

Testing Gaudí’s sound design

The visible curves in the photographs gave the team a starting point for provisional models of the three surfaces. They then compared geometric calculations to identify the parabolic form that best matched each section and assembled the full digital reconstruction.

The study also examined how the canopy may have worked acoustically. According to the researchers, Gaudí’s design created a defined area in front of the pulpit where a speaker’s voice would perform at its best.

The finished model is being stored in standard formats and can be requested by the research community. It can be studied, reused in teaching and research, and potentially recreated with digital manufacturing tools.

Topics: Culture

Source: Europa Press / Mallorca.com