In order to complement Schafer’s soundscape research, it is worthwhile as a field recordist to know about the methods of bio-acoustician and natural scientist Bernie Krause. Krause divides soundscapes into the categories geophony, biophony and anthropophony. To give you a practical illustration of the research, we present examples of our own field recordings captured on our recording trips.
The acoustic nature of natural soundscapes is significantly shaped by the sounds of geophony. The sounds of water, wind, weather, and earth movements form the basis from which the sounds of biological life must distinguish themselves in order to find their own niche frequency in the spectrum of sound. Geophonic sounds have always defined the character of natural habitats and have also been ground-breaking in the development of human sound culture.
The most common geophonic sound is water, whose dynamic forms create a large part of our acoustic experience. Since, until now, the lives of countless people take place in the immediate vicinity of rivers, lakes and seas, it is not surprising that myths and stories about water and its sound can be found early in history. The smallest geological and climatic changes are responsible for the acoustic richness of water. This becomes most obvious when observing various coastlines. While areas that are under a strong influence of the tides are characterized by the roar of waves breaking already at a distance, rhythmic and meditative waves dominate the soundscapes on southern beaches. Similarly, rain has different sonic characteristics depending on the subsurface and the strength of the precipitation. Over the course of time, man has invented a whole series of onomatopoeic terms to describe the subtleties of water: trickle, drizzle, splash, gurgle, splash, rush, rumble or foam. Apart from water, weather phenomena such as thunderstorms and wind are defining elements of geophony. Thunder is one of the loudest natural sounds in the world, and the sounds of the wind range from gentle breezes to thunderous storms.
The animal world reveals the greatest diversity of impressive sounds and each species has found its own place in the natural orchestration of the world in the course of evolution. By carefully analyzing the biophony of natural habitats, conclusions can be drawn about the intact nature of their populations. The vocalizations of animals follow set patterns depending on the time of year and day, providing the unique acoustic appearance of a place. Healthy habitats offer their fauna sufficient space to develop sonically; every call, chirp, roar, scream and croak is clearly articulated and can be noticeably recognized and distinguished. In urban spaces today, it is almost impossible to capture intact biophonies. The acoustic range and vocal niche occupation are usually only particularly obvious in biotopes such as rainforests, which are not yet under human influence.
Figure 1 shows a graphical representation of an evening biophony in the subtropical rainforest of Cát Bà National Park in northern Vietnam, recorded in February 2020. The x-axis maps time from left to right, and the y-axis maps frequency from bottom to top. In this spectrogram, it is immediately apparent that this is not a cacophonous jumble, but rather a well-orchestrated arrangement of insect, bird and mammal sounds, each occupying its own frequency niche. The voice of a bird occupies the highest place in the frequency range, followed by two species of crickets, one with a high sustained legato, the other with rhythmically repetitive sounds. In the lower part of the spectrum, there are the calls of a pair of monkeys, with the duet songs of the two animals always reaching the same pitch after the phrase begins, only to drift away from each other again.
Such a soundscape is almost impossible to capture in the modern world, especially in urban environments, where animal sounds can be masked by noise levels and hence are interrupted in their communication. The broadband urban background noise takes up most of the frequency spectrum and consequently ousts those animals whose calls are in precisely this range.
Anthropophonic sounds refer to all sounds produced by humans and their creations. Bernie Krause divides anthropophony into the sound types electromechanical, controlled, physiological, and incidental. Electromechanical sounds are almost omnipresent in the modern world, whether it be the incessant urban background noise of road and train traffic, the boom of airplanes, the buzz and hum of electrical appliances, or the noise of a construction site. Controlled sounds such as music, concerts and events are just as limited in time and space as physiological and incidental noises, which include any vocal utterances as well as body and movement noises. The latter form only a small proportion of anthropophony and can be readily controlled and limited.
The major part of the noise produced by mankind is therefore of electromechanical origin. In urban and industrialized environments, these noises generally occupy the entire frequency bandwidth, creating an impenetrable chaos of overlapping sounds. Working noises mix with the incessant roar of vehicles, machines and airplanes to form lo-fi soundscapes, which are complemented by signal noises such as horns or sirens.
Figure 2 represents the recording of an urban soundscape of the city of Bochum, taken from an observation tower in order to capture as many different sounds as possible at the same time. Even at first glance, the spectrogram reveals the dense cacophony of the soundscape, which on closer inspection looks not at all dissimilar to the abstract image of a built-up urban area. The diffuse background noise of the road traffic is amplified by a passing freight train and does not allow any differentiated hearing. The only sound that penetrates this acoustic abundance is the regular metallic screech of an angle grinder, which extends into those high frequency ranges that are not yet covered by the keynote sound.
The low information content of this soundscape does not allow transparent communication, but attracts a high degree of attention due to the persistent noise pollution. The relationship between signal and noise is almost impossible to grasp due to the superimposition of the various anthropophonic sounds.
We are happy if this article supports your sound journeys and that you capture awesome field recordings! Next month, we will delve into the topic of noise and show you the various effects of noise on people and the environment.