Vibro-acoustic immersive installations
I want to feel whalesong. I want to feel how I am in the water with them through sound — their physical reality.
Human bodies can feel sound. Below 20 Hz a tone loses its pitch, yet the body still receives it as vibration of varying intensity. Bass well above that is felt too: up to a few hundred hertz sound is heard and felt at once, in the chest, the abdomen and the skin. When we are submerged we hear with the entire body. Soft tissue has almost the same acoustic impedance as water, so there is no boundary at the skin. Sound passes straight in and reaches the inner ear through the bones of the skull.
The installations explore this multimodal bodily listening, the mix of the audible and the audio-physical. They extend beyond the loudspeaker and the headphone into infrasound: frequencies below 20 Hz, beneath what the ear can interpret. Surround loudspeakers provide the spatial 3D sound field. An infrasound-transduced surface adds the felt dimension.
A soft, inviting surface will be fitted with bass shakers that vibrate between 0.1 Hz and around 80 Hz. Listeners sit or lie down and listen through their bodies. The work is composed as a counterpoint between frequencies heard and frequencies felt. In this corporeal way it evokes the soundscapes of whales and of the ocean, including the sounds of its pollution.
Baleen whale song, from Bryde’s, blue and southern right whales, spans roughly 13 Hz to 20 kHz. It crosses the infrasonic and the audible spectrum of human hearing. Until now such sounds have usually been transposed upward into the audible range. That is not their authentic sound. Submarine earthquakes and much anthropogenic noise lie lower still, between 0.1 and 20 Hz.
For the first time it becomes possible to sense non-transposed whale song and ocean soundscapes across their complete spectrum, and to let listeners safely feel the immensity of sound in the sea. Infrasound is not presented here as a technical novelty. It is an artistic method for probing how sound shapes both cetacean and human perception. It opens a dimension of ocean sound that may prove restorative, and may also unsettle.
| Band | The body | The ear | In the ocean | In the installation |
|---|---|---|---|---|
| 0.1 – 1 Hz | Felt as slow motion or pressure change, like swell under a boat. | Nothing. No pitch, no tone. | Ocean swell, microseisms, distant earthquakes, seismic survey pulses, the hull and propeller of large ships. | Lower limit of the vibrating surface. |
| 1 – 4 Hz | Felt as sway. The band most associated with motion sickness. | Nothing at ordinary levels. | Earthquakes, storms, glaciers calving, seismic air guns. | Vibrating surface. |
| 4 – 8 Hz | The trunk’s main resonance. Organs and torso move most for a given input; a lying or seated person feels vibration most strongly here. | Nothing at ordinary levels. At extreme levels a sense of pressure in the ears. | Earthquakes, air guns, shipping. | Vibrating surface. |
| 8 – 16 Hz | Still clearly felt. Local resonances take over, the spine around 10 to 12 Hz. | At high levels perceived as separate pulsations, not a tone. | Lowest blue whale and fin whale calls begin around 10 to 15 Hz. Shipping and air guns. | Vibrating surface. |
| 16 – 20 Hz | Felt in trunk and head. | Threshold of tonal hearing. A rumble without clear pitch, needing about 75 to 80 dB to be heard at all. | Blue whale pulses, 15 to 40 Hz. Fin whale 20 Hz pulses. | Vibrating surface. Lower edge of the loudspeakers. |
| 20 – 40 Hz | Felt in chest and abdomen at concert levels. Head and neck resonance around 20 to 30 Hz. | Heard as the deepest bass. | Blue whale, fin whale. Shipping noise is loudest between about 10 and 100 Hz. | Surface and loudspeakers together. |
| 40 – 80 Hz | The chest wall’s own resonance. The classic felt bass. | Heard as bass. | Southern right whale up-calls begin around 65 Hz. Humpback moans and grunts. Shipping. | Surface and loudspeakers. Upper limit of the surface at about 80 Hz. |
| 80 – 250 Hz | Still felt in the chest and abdomen to about 110 Hz at high levels; above that whole-body sensation fades and skin sensitivity rises towards its peak around 250 Hz. | Heard clearly. Pitch becomes precise. | Southern right whale calls to about 200 Hz. Gray whale moans and knocks from 100 Hz. Humpback song’s lower register. | Loudspeakers. |
| 250 Hz – 1 kHz | Skin still sensitive to contact vibration, weakening towards 1 kHz. | Heard clearly. Speech and song sit here. | Humpback song. Right whale up-calls to about 440 Hz. Gray whale calls to 1.6 kHz. | Loudspeakers. |
| 1 – 8 kHz | Not felt. | The ear’s most sensitive band, peaking around 2 to 5 kHz. | Humpback song harmonics and cries. North Atlantic right whale scream calls, 400 Hz to 3.2 kHz. Dolphin whistles. | Loudspeakers. |
| 8 – 20 kHz | Not felt. | Heard, fading with age above about 15 kHz. | Upper reach of baleen whale song. Toothed whale whistles. | Loudspeakers, to their 20 kHz limit. |
| Above 20 kHz | Not felt. | Not heard by humans. | Echolocation clicks of dolphins and porpoises, to 150 kHz and beyond. | Not reproduced. |
| Underwater | Sound enters the body directly. Soft tissue and water have nearly the same acoustic impedance. | Hearing shifts to bone conduction through the skull, tens of decibels less sensitive and with almost no sense of direction. | Baleen whales likewise hear their lowest calls through skull vibration. | The vibrating surface approximates this whole-body reception in air. |
Measured means a hearing test on living animals. Sounds are played at controlled levels and frequencies and the animal’s response is recorded, behaviourally or through electrodes reading the auditory nerve. Human and dolphin hearing are measured this way, in many individuals over decades. The humpback row is measured in a thinner sense: migrating whales were played tones at four frequencies and watched for a response. It shows that they hear those frequencies. It does not give a full curve.
Modelled means no animal was tested. Researchers took anatomy, a fin whale skull in a CT scanner, the dissected middle ear of a minke, the measured dimensions of a humpback’s inner-ear membrane, and computed how that structure would transmit sound. These rows are predictions from physics and anatomy, not observations of hearing.
Estimated means a composite drawn up for regulation. The modelled results, the frequencies baleen whales are known to produce, and comparisons with measured species were combined into a deliberately wide group envelope for assessing noise impacts. It is a cautious policy figure built on the other two.