Soundscapes of urban public spaces have been changing because of the advancement of technology, social and political changes, as well as the ongoing climate and ecological crises. One of such changes in the contemporary neoliberal city is the acousmatic voice projected through a set of speakers into various public spaces, like the train and underground stations, hospitals, supermarkets, and schools. The acousmatic voice – when the source of the voice is hidden, unknown or removed – is used to address the citizens and guide, warn, suggest, declare, and dictate their everyday actions. The loudspeakers, voices, statements, technology, and other processes behind such public address (PA) systems are normally left unquestioned and operate behind a veil. Furthermore, the announcements in London are increasingly using pre-recorded female voices, which is a contrast to the predominant use of male voices even just a few decades ago. How do these voices change the way public spaces are structured, governed and regulated? What can architectural history uncover by studying soundscapes in and of public spaces?
As there is no historical or theoretical overview of their development, the thesis proposes to critically approach the rise of PA systems in urban public spaces to reveal the structural and societal mechanisms that construct the contemporary neoliberal city. Contemporary societies increasingly rely on technology to regulate urban public spaces, and London is known to be one of the most heavily surveilled cities in the world. An average citizen, for example, is caught on a CCTV camera more than 300 times a day. While the visibility of surveillance cameras (and security personnel) is meant to contribute to crime prevention, I suggested it is precisely the obscurity of loudspeakers and the overall ambiguity of PA systems that increase their effectiveness and promote their widespread use. As authors note in Spaces Speak, Are You Listening, ‘injecting noise of whatever kind into an acoustic arena is nothing more than the exercise of sonic power: social or political, autocratic or democratic, supportive or destructive.’ Who holds this power, and who determines how, where, or when it is exercised?
The securitisation of urban spaces is also part of wider issues around neoliberal and market-oriented redevelopment projects happening throughout London. Private corporations own and maintain public spaces in exchange to build more and bigger than what would otherwise be allowed under local zoning ordinances. This produces areas of privately owned public spaces (POPS) where people’s behaviour is subject to ambiguous or hidden rules set by individual corporations. As Brandon LaBelle neatly puts it:
[W]hat forms might being political take today when the power of people is contorted by operations and systems that are mostly never apparent or exposed, that are safeguarded behind racist and sexist mechanisms, that rely upon vague and volatile market forces, and that actively withdraw into secret arrangements and fluid networks, except in those instances when individuals make transparent, through acts of insurrection, the troubling work of governmental, militaristic or corporate agencies?
In various POPS in London visitors are not allowed to photograph or film, yet there are many CCTV cameras covering every angle of the space. A security guard will reproach you, or instead someone might even address you over the PA system and proclaim this is not allowed. As geographer Michael Gallagher writes, power is generally portrayed as exercised through technologies of visibility, that is ‘in the act of observing, exercis[ing] power over those who are observed’. As a response to LaBelle’s question, I suggested one form of being political then is focusing on sound in the built environment and conceptualising power as ‘ﬂuid and dynamic, even where it appears to be unidirectional or immovable’. Many hidden systems in place can surface through an embodied and situated critical practice of active listening. According to Jane Rendell, the boundaries denoting private and public spaces are never neutral, but culturally constructed contours that change historically and show specific value systems, just like urban soundscapes.
The way we hear today is different to the way people perceived their environment even only a few decades ago – listening is as much about physics and biology, as it is about culture. This thesis traces the development of PA systems by focusing on three historic moments that have defined their widespread use today. I analyse the ‘Speaking Statue’ presented in the first book on acoustics from the seventeenth century; the first modern version called the ‘Automatic Enunciator’ from Chicago in 1911; and the famous London Underground ‘Mind the Gap’, namely the first automated announcement implemented in 1969. I critically approach them by following a structure inspired by the PA system block diagram itself; starting with the architecture (the space into which the sound is projected), followed by technology and then focusing on the voice. The thesis maps different relations between public and private spaces, and theorises their contemporary intersections like in the case of POPS. Contemporary resistance to hidden governmental and corporate systems therefore could and perhaps should be auditory – the society that privileges vision is challenged through sound.
 Not only in London, but elsewhere in other Western cities as well. Ian Rawes, ‘Women’s Voices Call the Shots in Recorded Announcements - Sound and Vision Blog’, British Library: Sound and Vision Blog, 25 August 2010, https://blogs.bl.uk/sound-and-vision/2010/08/womens-voices-call-the-shots-in-recorded-announcements.html.
 ‘Research – Big Brother Watch’, Big Brother Watch, accessed 22 July, 2022, https://bigbrotherwatch.org.uk/research/.
 Barry Blesser and Linda-Ruth Salter, Spaces Speak, Are You Listening? Experiencing Aural Architecture (London: MIT Press, 2007).
 For more on neoliberal restructuring of cities see: Neil Brenner and Nik Theodore, ‘Cities and the Geographies of “Actually Existing Neoliberalism”’, Antipode 34, no. 3 (June 2002): 349–79, https://doi.org/10.1111/1467-8330.00246.
 Joanna Lowry, ‘An Imaginary Place’, in Theatres of the Real (Brighton: Photoworks, 2009), 82.
 Michael Gallagher, ‘Sound, Space and Power in a Primary School’, Social & Cultural Geography 12, no. 1 (2011): 49, https://doi.org/10.1080/14649365.2011.542481.
 Gallagher, 49. He is referring to Foucault’s conceptualisation of power.
 Jane Rendell, Art and Architecture: A Place Between (London: IB Tauris, 2006), 18.