A cathedral uses acoustic engineering to better their sound

Construction is underway in Raleigh, North Carolina, on the first new cathedral to be built in the United States in decades. From the building materials to the architectural design, engineers are using the latest acoustic technology to make sure both music and the spoken word resonate properly throughout this grand space.

TRANSCRIPT

Construction is underway in Raleigh, North Carolina, on the first new cathedral to be built in the United States in decades.

From the building materials to the architectural design, engineers are using the latest acoustic technology to make sure both music and the spoken word resonate properly throughout this grand space.

Here's a listen.

[ Machinery beeping ]

One of the biggest priorities for me is the acoustics, the sound.

I mean, 'cause you have a very, very big building here, and you have to be careful of the acoustics with the organ, as well as the spoken word.

And so we have hired experts, because, you know, if you have this beautiful building but people can't hear, that would be a frustration.

But, thank God, the expertise is there.

And we are fully invested in using the best information we can get so the sound is perfect, also.

But to really understand how well you will hear sounds inside the new Holy Name of Jesus Cathedral, you have to see the building while it is under construction.

So, don a hard hat, enter the narthex, or gathering space, just inside the new cathedral, then turn your eyes heavenward and see the skeleton that forms the nave, the cathedral's central aisle.

Then listen.

The sound is extremely important to engineer correctly.

And with the help of the Diocese of Raleigh choir, you can begin to understand how sacred sound will fill the space.

♪ I will praise your name forever ♪ ♪ My king and my God

Every inch of the 2,000-seat cathedral is studied for its acoustic properties, from the size of the worship space to the arches that top the walls and run the length of the building to the more than 200-foot-high dome to the transepts, or wings of the cathedral, the soaring altar, and all of the angles and corners in between.

♪ Worthy of great praise

The sound absorption and reflectivity of the building materials that will cover the interior are also analyzed.

That's the because the acoustic properties of the marble that will cover the floors differs from the layers of Sheetrock on the walls.

And multiple layers of Sheetrock absorb sounds differently than one layer.

♪ My king and my God

It all plays a part in making the Catholic Diocese of Raleigh's new cathedral come acoustically alive.

♪ I will praise the name of the Lord ♪

But when you look at all the construction materials, the size of the space, how many people are gonna be in the space, the materials of the pews.

Everything affects sound, to either benefit or become a hindrance to achieving the ultimate result that you're looking for for speech clarity, but then you can layer in the music performance into that, as well.

You heard correctly.

Acoustical consultants say, while music can fill a worship space and wrap people in a kind of sound blanket, understanding the spoken word is most important.

When you design technology into a space for either audio or visual support, you're affecting and affected by so many different things.

Speech is gonna be your number-one item that if you can't hear well and hear it intelligibly, then what's the point?

Once engineers understood the acoustic environment of the cathedral, they designed an acoustic model.

The sound properties of every seat in the cathedral are analyzed.

This is the wire-frame space.

It's like little faces, and on each side of that face, there's a material assigned to it.

And all that frequency's just like a piano, right?

So, at the low end, all the way to the high end of a piano, it has sound-absorption properties assigned to each material.

And something called scattering, which is, how well does that sound, if sound hits it, you know, how much of it continues on a path, like if you were shooting pool, or how much of it scatters and goes in multiple different directions?

Voices and choirs are recorded in a specially-designed studio.

The recording is then plugged into a computer program, which allows acoustical engineers to virtually hear how words and music will sound at any point in the cathedral.

It'll trace the sound to where you were sitting.

So, where the star is, for example, is where we're sitting in this case.

And, like, say the choir's in the back.

That might be a source.

And it traces that sound as it goes throughout the room and it gets absorbed and scattered until it arrives at that location.

Takes all that information, puts it into what we call an echogram, okay, and then you take the dry source and you take that echogram, and it convolves it and creates a binaural experience with both ears so you can hear it.

All of that information determines the type of sound system required.

You see multiple speakers shown here.

These are actually at different locations down the nave and in the transepts.

So there's not one loudspeaker.

This is essentially what we would call a distributed sound system.

So, the sound is carefully distributed so no loudspeaker's throwing more than a certain distance within this space.

Add to that, because we do not want to make this reverberant space more reverberant, we're going to aim that sound downwards, just into that area.

It all allows worshippers to hear heavenly sounds scientifically helped.

By the steerable loudspeaker, think of it as a parasol, and it collapses downward all the way around.

Now we're keeping off the walls, off the ceiling, and right on the people.

Oh, those are the ones who want to hear it.

[ Choir singing ]

So, all of the senses are being engaged.

So the sound becomes extremely important so they not only experience it in the beauty that they see, but then in the word that they hear, and all the other components where they encounter our Lord.

[ Choir singing ]