The Sound Book: The Science of the Sonic Wonders of the World Read Online Free PDF Page B

his house so that he could listen in and check whether the system was working correctly. 23 He was monitoring for faults in the system that might cause the sound circling between the microphones and loudspeakers to grow louder and louder, resulting in feedback, the howling and screeching we associate with heavy metal.
    Peter Parkin’s electronic system raised the reverberation time from about 1.4 seconds to over 2 seconds for low frequencies, vastly improving the warmth of the sound. But Parkin kept it secret. The use of electronic enhancement with classical music is so controversial that when the assisted-resonance system was first installed, it was brought in gradually without telling the orchestra, audience, or conductors. Once the full system had been covertly used for eight concerts, the engineers then dared to reveal its presence. The system was used until December 1998, when a nonelectronic solution was sought.
    I sympathize with the view that classical music should not be electronically enhanced, especially after hearing a demonstration of a different electronic system about twenty years ago in a theater near London. As the engineers switched between different settings, I heard strange mechanical and unnatural distortions, and the sound sometimes even appeared to come from behind me rather than from the stage. Amazingly, this was a demonstration designed to encourage people to buy the technology. Nowadays, however, modern digital systems, used in many contemporary theaters, can be impressively effective. I heard one demonstrated last year at an acoustics conference, and with a flick of the switch the lecture hall was transformed into a lyric theater or a grand concert hall with natural-sounding acoustics.
    A list of very reverberant spaces would include many mausoleums: the Taj Mahal and Gol Gumbaz in India, Hamilton Mausoleum in Scotland and Tomba Emmanuelle in Oslo, Norway. 24 The large rooms and hard stone walls make these places very lively.
    The artist Emanuel Vigeland built Tomba Emmanuelle in 1926 as a museum for his works, but later he decided to use it as his last resting place. Norwegian acoustician and composer Tor Halmrast, who is physically and aurally larger than life, described stooping to enter Tomba Emmanuelle—actually bowing beneath the ashes of the artist, which are in an urn over the door. Halmrast entered a tall, barrel-vaulted room covered with frescoes. He explained, “When entering, you see almost nothing, as the walls are very dark. After some time you see the paintings all over the walls and curved ceiling: everything from life (even copulation before life) until death.” 25 One fresco shows a plume of smoke and children rising from a pair of skeletons reclining in the missionary position. The midfrequency reverberation time is 8 seconds, a value you might expect in a very large church, which Halmrast thinks is remarkably long, considering that the room is relatively small. 26
    The explicitly sexual frescoes in Tomba Emmanuelle are in marked contrast to the dour interior of the Hamilton Mausoleum, but which is more reverberant? The world record was based on slamming the bronze doors of the mausoleum’s chapel—a very unscientific test. To properly compare the reverberation, one needs initial sounds of equal quality and strength. 27 If Rebecca Offendort from Hilaire Belloc’s cautionary tale “Rebecca Who Slammed Doors for Fun and Perished Miserably” were doing a measurement, she would “slam the door like billy-o!” and it would take a long time for the sound to dissipate. 2 8 A less vigorous experimenter would record a shorter time.
    For my visit to the Hamilton Mausoleum, acoustician Bill McTaggart brought along proper measurement gear. Across the room he placed on a tripod a strange-looking loudspeaker that sends noise out in all directions (Figure 1.1). It was an icosidodecahedron about the size of a beach ball. A microphone on another tripod