Acoustic Privacy

Incorporating sound control into the built environment
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Sponsored by LogiSon Acoustic Network
By Niklas Moeller

Learning Objectives:

  1. Define acoustic privacy and why it is important.
  2. Explain how speech intelligibility is measured within the built environment.
  3. Identify how to achieve acoustic privacy using various interior elements.
  4. Describe the impact of background sound levels within both open and closed spaces.


AAA 1 Structured Learning Hour
AANB 1 Hour of Core Learning
AAPEI 1 Structured Learning Hour
SAA 1 Hour of Core Learning
MAA 1 Structured Learning Hour
NSAA 1 Hour of Core Learning
OAA 1 Learning Hour
NLAA 1 Hour of Core Learning
NWTAA 1 Structured Learning Hour
This course can be self-reported to the AIBC, as per their CE Guidelines.

Typing the word ‘privacy’ into any search engine yields a virtually endless stream of entries describing the ways in which this basic human right can be violated. There are reports of hackers acquiring credit card information, law enforcement agencies mining social networking sites, and members of the public using drones to take aerial photographs. More recent headlines indicate that voice-activated electronics can eavesdrop on their owners.

Image of a lady holding a phone. Acoustic Privacy course main image.

Our preoccupation with the vulnerabilities exposed by the internet and electronic products is understandable given their relatively rapid spread into almost every aspect of our lives. However, we should not lose sight of the fact that privacy can still be violated in ‘traditional’ ways. In fact, it can even be lost to those who do not intend to infringe upon it. People are often exposed to sensitive information simply by being within audible range of a conversation.

Current privacy legislation tends to focus on securing access to information stored on computers or within filing cabinets, but attention also needs to be paid to our built environment. When examined in this context, privacy has both an acoustic and a visual component. This course primarily focuses on the former, except insofar as it is affected by the latter.

What is Acoustic Privacy?

Many immediately equate acoustic privacy with speech privacy, but there is more to this concept than the ability to clearly hear what another person is saying.

For example, even if the conversation taking place in the room next to you is unintelligible, you may still be able to identify the speaker’s tone and ascertain whether they are happy, sad, or angry. This type of information can be considered private under certain circumstances, such as when issuing from behind the closed door of a human resources manager’s office. The same can be said for nonverbal noises like those overheard from an adjacent hotel room.

How much we understand of a conversation also depends on whether or not we can see the speaker. This effect—known as visual cues—has been quantified by various studies. Generally speaking, if you can only understand 20 percent of someone’s conversation when you are not looking at them, the ability to see their lips increases that amount to nearly 55 percent. If you start at 50 percent, visual cues increase it to almost 90. In other words, there is also a visual component to acoustic privacy, which is important to bear in mind when designing a space.

Furthermore, acoustic privacy should not only be considered from the perspective of the person speaking but also that of the listener(s). The reasons will become clear when we explore the various impacts of a lack of privacy.

A patient holding her head and doctor touching her shoulder

If we visit a medical clinic and hear what is happening in the adjacent examination room, we might be less inclined to disclose information to the nurse or doctor, knowing that we too can be overheard.

Where is it Needed?

A lack of acoustic privacy carries real risk, particularly in facilities where there is a perceived need for it or an expectation on the part of its users. Examples that readily spring to mind include hospitals, bank branches, law offices, government, and military facilities. However, other types of spaces—such as commercial offices, call centers, and hotels, to name but a few—have privacy needs as well. The degree required typically depends on the type of activities the space hosts.

Why is it Needed?

It is easy to understand the need for acoustic privacy—or even acoustic security—from a speaker’s perspective, particularly in environments where they are discussing medical information, financial planning, personal relationships, trade secrets, matters of national security, and similarly confidential topics. However, a lack of acoustic privacy can have impacts beyond divulging sensitive information to unintended parties. This fact becomes clear when we shift our perspective from the person talking to that of the involuntary listener.

When a noise or voice enters ‘our space,’ some degree of annoyance is typical, but it can also make us feel as though our privacy is being invaded or our sense of physical separation from others violated. Perhaps the most relatable examples of this sensation are when the guest in a neighboring hotel room turns up the television volume or the patient at the other end of a waiting area starts speaking loudly into a cell phone.

If we can inadvertently hear a conversation, we can also become self-conscious about our own level of privacy. In some contexts, it can create a sense of unease, which in turn impacts our ability to freely communicate. For instance, if we visit a medical clinic and hear what is happening in the adjacent examination room, we might be less inclined to disclose information to the nurse or doctor, knowing that we too can be overheard.

The degree of acoustic privacy afforded by the built environment can even impact an organization’s brand image. We want to be in control of our personal information when meeting with a financial or legal advisor, for example, and a positive acoustic experience can reinforce our confidence in the firm. This level of protection is also indispensable for staff to effectively negotiate the terms of various agreements.

In some countries, protecting verbal communication within particular types of facilities is actually mandated by law. The Health Insurance Portability and Accountability Act (HIPAA) introduced by the U.S. Department of Health and Human Services in 1996 is a good example. It requires health-care entities to take “reasonable safeguards” to ensure speech privacy during both in-person and telephone conversations with patients and between employees.

Acoustic privacy is also vital to employees’ overall satisfaction with their workplace. A decade-long survey of 65,000 people run by the Center for the Built Environment (CBE), University of California, Berkeley, found that lack of speech privacy is the number-one complaint in offices. Participants expressed irritation at being able to overhear in-person and telephone communications, as well as concern for their own level of privacy.


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Originally published in Architectural Record