Audio Theory 2: Listening Blog 1
Skandalakis’ (2018) photograph of Lake Arhuaycocha at the foot of the Arhuay glacier, Huascaran National Park, Peru.
Stratis Skandalakis’ aural snapshot of Lake Arhuaycocha in Peru, published in 2018 captures the beautiful and icy landscape in 3D through the use of binaural recording. This technique is used to create a realistic sound by replicating the way our human ears perceive sound. Our brains use information from the relationship between our ears, head, and external sound waves to instantly localise sound sources.
With our head occupying space between the ears, sound arrives at both ears at slightly different times and levels depending on which direction it is coming from. These subtle differences in time and loudness contribute to the spatial localisation of sound sources and are called the Interaural Time Difference (ITD) and Interaural Level Difference (ILD). Additionally, the shape of the pinna and ear canal further influences the way sound is perceived. Level and mid-high frequencies from the front and sides are enhanced by the pinna, whereas those from behind are reduced. The head also creates a shadow and thus generates more distinct time and level differences between the two ears.
Blake's (2020) image shows how subtle differences in time and volume of sounds received by each ear.
These properties of human anatomy and sound are the jumping board off which binaural technology was developed. Binaural microphones typically consist of two omnidirectional microphones spaced approximately 17cm apart inside a dummy head with anatomically correct silicone ears. This setup replicates the way sound reaches our eardrums to fully capture all the ITD and ILD cues as well as the frequency adjustments from the shape of our ears. However recordings made with a dummy head will always pick up different ITD and ILD cues every individual, as we all have unique proportions. Furthermore, binaural recordings only produce an immersive 3D effect with headphones, as the spatialisation cues are isolated for each ear. With a loudspeaker setup, the crosstalk would lessen the stereo effect.
Two DPA 4060 microphones were used in Skandalakis’ recording. With a diameter of 5.4mm each, these sit inside the ear canal which captures the idiosyncrasies of listening with the recording engineer’s personal anatomy rather than a dummy head. DPA 4060s are true omnidirectional microphones and thus have a flat frequency response, no proximity effect, and an SRA of 360°. This means that the directionality and shaping of the sound therefore comes from the shape of Skandalakis’ ear canal, pinna, head, as well as their torso to a certain extent. Not only is this minimal setup a more personal recording choice than the dummy head, it is perfect for their lifestyle as a “vagabond travelling, equipped with a high dose of curiosity, thirst for knowledge and adventure, some fancy microphones and [a] hammock” (Skandalakis 2017, para. 1).
DPA 4060 Series Miniature Omnidirectional Microphone (2021)
This recording is clear and bright, with a crisp high end and well-rounded mids and lows that expresses the depth of the landscape. In the foreground of the soundscape is the gentle trickling and bubbling of water, whilst the background is filled with the soft noise of waterfalls and reflections off ice, with the odd chirp from some kind of insect. An avalanche roar is captured in the distant background halfway through and the reflections can be heard bouncing off the mountains. The avalanche sounds huge yet far away through the use of binaural recording and spatialisation cues it picks up. Meanwhile the trickles and splashes of water seem within an arm’s reach.
Binaural recording also plays a critical role in the way Skandalakis draws influence from Murray Schafer’s research into soundscapes, sound ecology, and the “idea of a holistic acoustical consideration of a recording” (Skandalakis 2017, para. 3). In Schafer’s book The Soundscape, originally published in 1977, he notes that researchers (including himself) in soundscape studies have posed similar questions: “what is the relationship between man and the sounds of his environment and what happens when those sounds change?” (Schafer 1994, p. 3) Soundscapes are likened to photographs but instead “consist of events heard not objects seen” (Schafer 1994, p. 8). He argues that although there is widespread use of photographs, the lack of accurate soundscape notation makes us “disadvantaged in the pursuit of a historical perspective” (Schafer 1994, p. 8). 40 years later with advances in microphone technology, Skandalakis’ binaural and ambisonic recordings provide us with a realistic glimpse into the experience of aurally observing these natural soundscapes.
References Blake, J 2020, How to Record Binaural Audio (Methods and Equipment), online image, viewed 17 June, 2021, https://acousticnature.com/journal/how-to-record-binaural-audio
Schafer, M 1994, The soundscape: our sonic environment and the tuning of the world, Destiny Books, Rochester.
Skandalakis, S 2017, ‘Introduction’, Binaural Recordings, viewed 17 June, 2021, https://www.binaural-recordings.com/blog/hello-world/
Skandalakis, S 2018, ‘Soundscapes of nature: Recordings of exceptional natural habitats - Biophony and Geophony’, Binaural Recordings, online image, viewed 17 June, 2021, https://www.binaural-recordings.com/listen/