MILAN, Italy — Does your church sing? Or does its message fall flat in a mess of reverberation, boomy bass and muffled speech?

Researchers here are investigating the subjective acoustic qualities of church architecture in one of the most extensive scientific inquiries yet.

By studying the best-sounding spaces (and the worst), the researchers hope to assemble practical design criteria for new churches. The data can also provide the clergy with some considerations on what music works best in existing places of worship.

Since 2000, the team has visited 40 churches from Gothic to contemporary in style. They picked nine of the buildings for a five-song test of their acoustics.

When the churches closed to worshippers at dusk, engineers and acoustic experts brought in sound-test dummies outfitted with binaural microphones. By plugging a microphone into each of the dummy’s ears, a close approximation of the human listening experience could be recorded.

Over a three- to four-hour period, the dummy sat in about 10 different pews while it “listened” to songs including the overture from Le Nozze di Figaro and the Gregorian chant Pange Lingua. The team also recorded each spot with 3-D SoundField microphones for comparison.

“At first, the priests weren’t really sure about us. They thought we wanted to sell them something,” says Francesco Martellotta of Bari’s Politecnico University, which spearheaded the study. “But now they understand that sound quality doesn’t just depend on the speakers they’ve got.”

Back in the lab, volunteers listened to each song as it was recorded in two different churches, then chose which one struck the right chord.

“Human perception in a church is very important, but we took people out of the church environment for a more scientific take,” says Christian Skaug, a researcher at the Italian National Research Council, or CNR, who made a mathematical model for the data.

“There’s often an abyss between scientific evaluation and human evaluation,” he says.

Preliminary findings suggest listeners prefer sounds from paleo-Christian churches with their insulating wooden ceilings. Baroque buildings, with their heavy stucco decorations and contained spaces, were also right on key. Cavernous Gothic buildings fared worst: Bologna’s San Petronio Basilica, about 430 feet long, was a listener’s nightmare with 12 to 13 seconds of reverberation.

A book compiling the first round of findings called Worship, Acoustics and Architecture, comes out in paperback in April.

The clergy sometimes seeks out a scientific take on a church’s acoustics. In 1997, priest Silvano Burgalassi approached the National Research Council about studying the extraordinary acoustics in Pisa’s Baptistery.

The dome of the building was left open to collect water for the baptismal font, then later closed, making for a unique vibe.

A team led by Leonello Tarabella, head of the Research Council’s Computer Music Lab, sounded out the 180-foot-high round building normally overshadowed by the nearby Leaning Tower. Inspired by the Baptistery’s particular aural characteristics, Tarabella then composed a piece of music called Siderisvox (Latin for “voice of the star”) to make the most of its peculiarities.

For two nights in 2006, he turned the Baptistery into the world’s largest musical instrument, creating a 15-minute sound fresco for groups of about 200 people at a time. Tarabella hopes to release a CD of the experiment later this year.

An event photo shows Tarabella orchestrating from a laptop, half hidden behind a piece of rectory furniture.

“In the end it’s not about scientists,” says Tarabella. “It’s about exploring the use of sound in a very particular place.”