Whispering wall: Barossa reservoir

This vast, gray arc of concrete has turned into an unlikely tourist attraction, with visitors chatting with each other from opposite ends of the dam.

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It’s unbelievably fun to whisper across this parabolic dam and hear others across the way.

revett2016, TripAdvisor

This is the largest whispering wall I know of, as it’s 140 meters long. What happens is that the sound hugs the inside of the concrete wall and is transported with surprising loudness to the other side of the dam. Do you know of a bigger whispering wall? Please comment below.

It’s worth not fast forwarding this, because you get a sense of how far the sound travels.
How sound hugs the wall in a whispering gallery amd keeps close to the curved wall.


Info from the Barossa visitor centre.

Photo credit

Scott Davis, CC BY-SA 3.0

Gloucester cathedral whispering gallery

The whispering gallery (or tunnel) runs behind the magnificant Great East Window

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Doubt not but God who sits on high,

Thy secret prayers can hear;

When a dead wall thus cunningly

Conveys soft whispers to the ear.

Plaque in the gallery

Classic whispering galleries usually have obvious curved surfaces to allow sound to travel long distances without getting too quiet. This isn’t what is happening here. As the video shows you have a tunnel within which the sound can’t escape, and so travels easily from one side of the cathedral to the other.

Great demo of the whispering gallery

The first documentation of this comes a meeting of the Royal Society in 1662. Such scientific luminaries as Robert Boyle (a founder of modern chemistry) had been discussing echoes and sounds and sought further information about the whispering gallery from politician Henry Powle.


See Gloucester Cathedral website. While you’re there, you can also enjoy the reverberation in this huge cathedral (reverberation time about 8 seconds apparently).

Photo Credits

© Julian P Guffogg (Creative Commons Licence)

Clonmacnoise whispering arch

Whisper into one side of this ornate doorway and the architrave carries the sound to the other side.

This ornate Gothic doorway dating to the fifteenth century is apparently a popular spot for wedding proposals. Folklore has it that the doorway once had a very unusual use: Lepers would stand at one side of the doorway and whisper their sins into the half pipe in the architrave. The priest would stand at the other side of the arch, far enough away to avoid infection, listening to the confession emerging from the architrave.

Like all whispering arches, sound skims around the inside of the curve because of the geometry – see below for a simple model of sound as a snooker ball bouncing around a circular table. Being a half-pipe probably helps keep the sound close the arch.

A whispering arch


See Heritage Ireland for more details about visiting.

St. Louis Union Station Whispering Arch

This sound effect was discovered when “a workman dropped a hammer on one side of the arch and a painter on the other side, nearly 40 feet away heard him.”

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The whispering arch is a treat, talk towards the wall and someone 20 yards away can plainly hear you. pretty cool.

Aquariuz, Trip Advisor

The whispering arch is the structure to the left in the old postcard, there’s a plaque marking the spot. This whispering arch dates back to when the building was a large railway station in the nineteenth century. When someone talks into the wall, you can get sound that stays close to the edge of the arched ceiling. A classic way of illustrating this is to consider sound as a snooker ball bouncing around the edge of a circular table.

Sound in a whispering arch modelled as a bouncing ball


In the lobby of the St. Louis Union Station Hotel. Head for the stained Tiffany glass window featuring three robed women figures.


Photos: Public Domain and onasill

Gastown steam clock

This clock produces a whistled version of the Westminster Chimes.

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The World’s first steam powered clock has been created for the enjoyment of everyone

From the plaque on the clock

The Westminster Chimes ringing out from Big Ben is a familiar sound. A breathy version of the same tune is also played by this clock. The notes are created by steam being forced through whistles.  Built in 1977, the whistles are driven from the system of underground pipes that supply steam to heat downtown buildings.


305 Water St, Vancouver, BC V6B 1B9, Canada. Best heard on the hour.

There are other similar steam clocks in The City of Otaru, Japan, and the Indiana State Museum.


Photo: By Leonard G.

High tide organ

A ‘musical manifestation of the sea’ is created by this sound sculpture.

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Built in 2002 and designed by Liam Curtin and John Gooding, this organ stands next to Blackpool’s promenade. A narrow tall rusting sculpture shaped like a fern in spring beginning to unfurl, forms the most visible section of the wave organ. The sculpture uses church organ pipes that are sounded by air being forced through them by the ebb and flow of the sea waves. The music made depends on the vigour of the sea, sometimes it intermittently moans and groans, at other times it resembles a lazy orchestra of train whistles, or a slow-action replay of a nightmare recorder lesson.


South Promenade, Blackpool FY4 1BB. Sounds best 2-3 hours before or after high tide. If the sea is calm, you won’t hear anything!

Musical Stones of Skiddaw

Try your hand at rock music on this Victorian instrument played by the “Original Monstre Stone Band.”

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Queen Victoria heard command performances of Handel, Mozart and Rossini on this large stone xylophone. It took Joseph Richardson thirteen years to construct this lithophone out of hornfels slate from the Lake District. The vast instrument is in the Keswick Museum and Art Gallery in Cumbria, where I was amazed to be encouraged to have a go. The tone varies across the instrument. Some stones ring beautifully, like a wooden xylophone, while others make more of a thunk, like a beer bottle being struck with a stick.

Original advert from the London Gazette in 1845

One historical account recalls, ‘The tones produced are equal in quality, and sometimes superior in mellowness and fulness, to those of a fine piano-forte, under the hand of a skilful player.’


Keswick Museum, England

Imam Mosque echo

Tour guides delight in standing underneath the dome and flicking a piece of paper, which creates a short, sharp “clack, clack, clack, . . .”

This Mosque was completed in 1629, in the last year of the reign of Shah Abbas. Sound bounces back and forth between the floor and ceiling, with the vast dome focusing the sound, forcing it to keep moving back and forth in a regimented fashion. Without a dome, the echo from the ceiling would be lost among all the other sound reflections in the mosque. The iconic blue-tiled mosaic tiles help to provide strong reflections, which is why so many repeats of the echo are heard.

A domed room focusing sound
You can also excite the echo by stamping your feet


Esfahan’s main square


Photo: seier+seier


A spherical room that allows you to whisper sweet nothings in your ear!

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The Mapparium is a giant hollow globe of the world, with the seas and continents vividly drawn on stained glass. It was built in 1935 following a suggestion by architect Chester Lindsay Churchill. It took eight
months to paint and bake all 608 glass panels, which are mounted on a spherical bronze frame.

You traverse a walkway cutting through the center of the Earth linking up two opposite points on the equator. Three hundred lightbulbs illuminate the globe from the outside. Looking at the world from the inside out is an odd experience, but what also strikes visitors are the strange acoustics, which were an accidental by-product of the geometry.

One of the effects you’ll hear is false localisation:

“Suppose you are on the Mapparium bridge facing South America. There is a source of noise to your right, but you discover that you hear the noise coming from your left!”

William Hartmann, Michigan State University

This happens because the reflections from the globe are focussed and very loud. Your brain thinks the sound is coming from the reflection direction and not direct from the source. This focussing also allows you to do things like whisper in your own ear!

As you approach the exact center of the Mapparium sphere you suddenly become aware of strong reflections of your own voice . . . If you sway to the left, you hear yourself in your right ear. If you sway to the right, you hear yourself in your left ear.

William Hartmann, Michigan State University


Marky Baker Eddy Library in Washington. They have regular tours. At the end of my tour, they allowed us to linger a little to play with the acoustics.


Photo: Smart Destinations

Sound Sculpture Tvísöngur

Looking like a cluster of igloos, this sound sculpture is ideal for traditional Icelandic singing.

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“It is great fun visiting this work of art, trying to sing in all the domes teaches one a lot about acoustics. This area is quiet and tranquil and one doesn’t have to feel embarrassed about raising one’s voice to sing out loud”

Regína Hrönn Ragnarsdóttir

Constructed from smooth thick concrete, each of these reverberant chambers has been tuned to a different frequency corresponding to a tone in traditional Icelandic five-part harmony. It’s by German artist Lukas Kühne and is called Tvísöngur or The Duet. You can hear the resonances either by singing, or through the wind whistling through the openings.

Here is a short snippet of singing without (anechoic) and then with the sculpture.

Anechoic singing
Singing in Tvísöngur

Impulse responses are available for the sculpture if you want to use them in a convolution reverb.


Tvisongur is located on a mountainside above the town of Seydisfjordur. It is a 15-20 minute hike on a gravel road that starts across from Brimberg Fish Factory. Open all the time to visit.


Photo: Navin Rajagopalan

Sound samples: Oliver McIntyre