In Sonic Wonderland/The Sound Book, I wrote about the Emanuel Vigeland Mausoleum in Oslo, Norway. It was recommended to me by Norwegian acoustician and composer Tor Halmrast who told me it was the most reverberant place for its size that he had ever met. When I was in Oslo last week, I took the chance to experience this remarkable place first hand.Emanuel Vigeland was an artist, who built Tomba Emmanuelle in 1926 as a museum for his works, but later decided to use it as his last resting place. To enter the mausoleum you have to stoop through a small door way, actually bowing beneath the ashes of the artist which are in an urn over the door.
Every surface of the tall barrel-vaulted room is covered with frescos. It is even gloomier than the picture above shows, with the walls being very dark. The walls and ceiling are covered in every aspect of life from conception to death, including some extremely explicit images. My favourite was above the door, where a plume of babies rise above a pair of skeletons reclining in the missionary position.
Tor was right, the space is incredibly reverberant. Sing a note and it takes about 10 seconds to die away. It is also a very pleasant reverb, it seems like the sound gently cascades down onto you from the arched roof above. No wonder this place is regularly used by musicians.
To measure the acoustics, I recorded a balloon burst on a digital recorder, and later analysed the recording to calculate the reverberation time, which is a measure of how long it takes a sound to decay by sixty decibels. Here is one of the balloon bursts:
You can download the balloon bursts in wav format from freesound.orgThe graph shows the reverberation time at various frequencies. For frequencies where speech is important (500 Hz – 2 kHz) the reverberation time is about 13 seconds , rising to 18 seconds at low-frequency. So how does this compare to other spaces I have visited? It is very similar to the Hamilton Mausoleum near Glasgow that up until 2012 used to hold the World Record for the longest echo. Neither mausoleum, however, comes close to the current record holder, number 1 oil tank at Inchindown, Scotland.
Tor was right, the Emanuel Vigeland Mausoleum is unusually reverberant for its size. This happens because every surface is granite or concrete. Importantly, there are no longer any windows that would otherwise vibrate and allow the sound to escape to the outside. Also, the frescos are sealed with wax, so they have clogged up the pores of the concrete walls.
A visual and aural treat, and definitely worth visiting if you’re in Oslo. If you do, try dragging one of the chairs across the floor.
 Photo credit: http://www.emanuelvigeland.museum.no/museum.htm
 The reverberation time graph is an average of three balloon bursts taken from roughly the same place in the mausoleum (I don’t know why I didn’t use three very different places!)
 This is longer than the reverberation time given in Sonic Wonderland/The Sound Book, which was based on measurement by others.