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Are You Listening? Basics of Investigating (with) Sound

This article is an introductory journey intended for anyone with an interest in listening – yes, that’s right, listening NOT hearing – and possibly using sound as evidence when researching and investigating various aspects of the surrounding environment.

By Antye Greie-Ripatti (aka poemproducer AGF) and Tyler McBrien. Further contributions by: Marek Tuszynski, Filip Milošević, Laura Ranca


Let's start with a listening exercise

  • Go to a space where you will be safe and undisturbed for a moment.
  • Set an alarm for 1, 5 or 10 minutes.
  • Close your eyes and listen.
  • Listen to what is around you, behind you, in front of you, above and beneath you, all 360 degrees.
  • Ask yourself: What is the loudest sound? What is the quietest? Which sound is pleasant? Which is disturbing?
  • In your mind be sure to focus in on different sounds.
  • Relax and just keep listening until the timer is up.

For more listening exercises visit: https://www.unseen.help/agf-en/

Image credit: Poemproducer/AGF: https://www.unseen.help/agf-en/

Sound is everywhere on earth. Human hearing is a unique capacity, distinct from our other senses. Listening is the capacity to translate what we hear to the brain or, as musician Pauline Oliveros says, to consciousness.

Listening is different from Hearing. While we hear all the time (except the deaf), listening involves a higher attention investment and voluntary energy to focus, with a purpose and a meaning. Listening is a crucial use of our hearing capacity in investigations. The sound we hear can tell a different story than visuals or written words. Sound can be listened to under different circumstances, whether driving or walking or washing dishes. Sound is not only what we can hear, it exists in a much wider spectrum of sound waves. Sound is also data, information and evidence.

Because of this unique space occupied by sound, it is an effective, albeit often overlooked, element of investigation. Sound can serve as an important method for gathering evidence, or a vehicle for conveying your findings to a receptive audience.

So, how exactly can you incorporate sound into your investigations?


The potential of sound: cases to inspire you

There are so many examples of the use of sound in investigation. Even when not intentionally recorded, sound can be used to analyse key evidence.

Sound can help tell stories of empathy and understanding, especially with more abstract topics. For example:

  • In "Listening to Rivers" from 2020, sound artists Leah Barcllay and Annea Lockwoood hosted a listening session and talk focusing on the rich, immersive soundscapes of rivers.
  • In "ONE PIG" (2011) the artist Matthew Herbert documents harrowing conditions of animal farming using recordings of an entire life of a farm animal.
  • The recording of a whale in 1970 managed to bring to light a story not understood by humans, see "How pop music helped save the whales": "Only one non-human species has ever had a hit record: whales. When whales were first recorded, they became really big."

To get a detailed sense of what is possible to do with sound/acoustic investigations in particular, Forensic Architecture - a research agency based at Goldsmiths, University of London - offers an impressive array of cases and methods. The agency's work focuses on "investigating human rights violations including violence committed by states, police forces, militaries, and corporations." For instance, in sound investigator Lawrence Abu Hamdan's work with Forensic Architecture, he conducted a complex analysis of sound made by bullets, which helped determine who killed two teenagers in Palestine in 2014.

Another inspiring example of acoustic investigation from the same collaboration and Amnesty International shows how investigators were able to reconstruct the architecture of a secret prison in Syria based on sound memories of interviewed prisoners who were kept there blindfolded. See more about the methodology here.

In another case from Forensic Architecture - "Killing in Umm Al Hiran" - investigators took sound from one video that was not capturing the situation under investigation (however the sound did) and matched it with soundless video of law enforcement. That allowed them to prove a very different narrative to the one officially promoted by authorities.

Besides these more unusual tactics of using sound to investigate and expose issues, there are also traditional ways of using sound.

Take the example of forensic voice analysis as in the case of the investigation conducted by The Insider and citizen investigations group Bellingcat into the downing of the Malaysian Airlines Flight 17 (MH17) over eastern Ukraine - where the team used voice analysis to identify a key person of interest (namely Colonel General Nikolai Fedorovich Tkachev) in the Russian military communication at the time when the passenger plane was shot down with a missile. For a detailed description of how forensic voice analysis was used in this investigation, read the full Bellingcat documentation.

As the above examples illustrate, using sound as evidence is just one way to incorporate it into your investigation. But with analysis, editing and transmission, the possibilities multiply:

  • Recorded sound allows for repeated listening, and can serve for documenting, verifying and building a body of evidence
  • Forensic and other forms of sound analysis can lead to clues and revealing of hidden facts
  • Sound editing can help with effective storytelling.

Recording sound: a mini audio field guide

For some investigations, you will be seeking out entirely new sounds to capture, either for evidence or narration. Whatever the purpose, check some tips to record the highest quality sound with the recording equipment you have at hand.

Note that because it's a unique medium, sound comes with its own set of considerations and ethics when used in investigations. Before hitting the record button, it's important to ask yourself some questions:

  • What is the relationship between the recorder and the recorded? What are the power relations?
  • What 'territory' am I on and whose space is it? Do I have the right to / is it ethical to be there?
  • Do I have or do I need permission to record? Am I openly recording or am I recording sound secretly, for instance as part of an undercover investigation?

After answering these ethical questions and deciding whether to move forward, planning your recording is next. The choice of recording technology is very important and should be suited to what you'd like to do.

Here are a few resources on microphones and other recording tools as well as audio recording and processing tips you can incorporate in your investigations.

General information and recommendations

Microphones

Portable audio recorders

Other essential equipment

Before setting off to record, remember to prepare and pack the following:

  • headphones (invest into a good one that lasts and you get used to);
  • fully charged audio recorder or dictaphone;
  • binaural microphones attached to phone/tablet;
  • selection of AA, AAA and 9V Batteries;
  • data storage media: SD cards, Hard disks, etc.;
  • camera, tripod.

Recording tips

Once you have selected your equipment, it's time to record! As you do, keep these recording techniques in mind:

  • Levelling is the most important thing! Be mindful of the distance between the microphone and what you want to record, and always test the levels before recording. For more on levelling, watch this video: https://www.youtube.com/watch?v=6UH6CXc6dWI
  • Protect from pops using a pop screen / pop filter
  • Wind is your enemy! If you have wind, always use a microphone wind shield or windscreen (see more about them here or here). While pop-screens give protection from unidirectional blasts, foam "hats" shield wind into the grille from all directions, and blimps / zeppelins / baskets entirely enclose the microphone and protect its body as well. The latter is important because, given the extreme low frequency content of wind noise, vibration induced in the housing of the microphone can contribute substantially to the noise output.

For a deeper dive on recording techniques visit: https://etherpad.wikimedia.org/p/selfrecordingtips (maintained by poemproducer / AGF)

Editing sound

Recording clean, sharp sound is in many ways only half the battle. Analysing, repackaging, and editing that audio in a way that is most accessible and compelling to your audience also takes time and skill, though these skills are well within reach to anyone. This process is called postproduction, and can include the following:

  • Listening to and transcribing the recordings
  • Evaluating, analysing and editing recordings in a Digital Audio Workstation (DAW) - for example, Audacity is a popular open-source DAW
  • Audio postproduction (equalization / EQ, compression, noise cancellation)
  • Audio Mastering
  • Self-publishing or uploading to desired platform.

Though similar rules of storytelling apply to audio, "writing for audio" is a distinct skill, emphasizing short words, short sentences, one idea or fact per sentence, and a simple sentence structure. For more on writing for audio, check out these resources:


Be creative about working with sound

Recording new sounds from scratch may not always be necessary to accomplish what you want with sound in your investigations.

Found recordings

You can work with sound created by others and found by others, even if you were not involved in the process of capturing it. Make sure you respect the copyright rules and respect and protect the sources. Also be sure you consider all data included in the found recordings.

Sound archives

Many of these found recordings can be located in sound archives, which allow you to search for recordings in a certain environment or action. Also be mindful of the licenses attached, which can dictate how you can use the recordings. Some archives to check out:

Sound explorers and specialists

Just as there are weather spotters, trainspotters, plane spotters and other people passionate and experienced with tracing and recording movements, events and phenomena, there are certainly people passionate about recording sounds. Among them are those who specialise in field recording - some might be musicians, technicians, some might be hobbyists or else. They might be in places where nobody was when something was happening and might have relevant recordings. Consider this when looking for information or inspiration in the form of sound and other recordings in an area or a theme of interest to your investigation, and identify such experts and explorers around you and your networks / collaborators.

Beyond what you can hear

Using sound as evidence generally assumes that you or others can hear it and analyse it. However, you can venture beyond the obvious and consider what may be inaudible sound. There are sounds present outside of human hearing range - that can be made by different types of machines and devices as well as natural phenomena (for instance a dog whistle, or seismic waves.) Sound is also used by various detectors such as metal detectors - here sound is generated in reaction to changes of sensors input by objects the sensor is trained to detect and signal.

There are also uninteresting, monotonous sounds that can carry information. A radical example is this research into how computer hard drive sounds can transmit data from a PC (see original technical research paper here.) Moreover, there is acoustic intelligence in machines and it could be explored to not only test and find if and where they might break but also to identify other types of actions that may occur in spaces and environments. For example, factories could be releasing forbidden pollution at night, which if not visible may generate recordable sound produced by machines, released substances, etc. The options to explore sound and to investigate with sound could be endless while the limit is only set by one's creativity. Just remember to listen more.

Did you like this article and want to send us feedback or share something related? Reach out to us at eti@tacticaltech.org if you have suggestions of other inspiring cases, methods and techniques of using "listening" and sound in investigations. We'd love to explore this path further.


This article is part of a series of resources and publications produced by Exposing the Invisible during a one-year project (September 2020 - August 2021) supported by the European Commission (DG CONNECT)

European Commission

This text reflects the author’s view and the Commission is not responsible for any use that may be made of the information it contains.

First published on January 24, 2022

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