Designing an experience for individual sound zones in cars

Harman International, Industry Sponsored Project

UX Designer & Researcher, Aug - Dec 2021
Harman International approached us to explore how we can design a user-friendly experience that integrates their new technology ‘Individual Sound Zones’ or ISZ into the physical space of a car.


This project only covers low fidelity wireframes, and does not cover high fidelity design.

Due to the exploratory nature of this problem space, our aim of this project was to test multiples prototypes we created on the basis of exhaustive user research. End deliverables of this project were research findings, prototypes and the results of our usability tests.

In-Car Experience: Personal Audio Zones


Eryue Xu, Sandeep Prasad, Xi Pang, Mudra Nagda

& Duration

Harman Internation
August - December 2021


UX Researcher
Defining the Problem Space & Use Cases, Stakeholder Analysis, Survey, User Interview, Persona Mapping, Empathy Mapping, Storyboarding

UX Designer
Sketches, Wireframing, Usability Testing



What are Individual Sound Zones (ISZ)?
The ISZ technology creates individual sound zones for each user in a car, which enables them to personalize their audio experiences with zero to limited disturbance from other passengers in the car. Harman achieves this by using positional, directional, planar and unity speakers. Since the focus of this project is user research, the team at Harman encouraged us to not to be restricted by any technical limitations.

What are some of the use cases of ISZ?
ISZ has several use cases, each stemming from the placement of the passenger in a car & their goals pertaining to entertainment. Harman gave us some broad use cases to understand the context in which ISZ will be used

Defining the Problem

"How might we design an interaction that enables families to use Individual Sound Zones in a car?"

Our Approach

01 - define

Understanding Problem Space

Defining project goals

Expected methods

Forming a schedule

02 - research

Competitive Analysis


User Interviews

Task Analysis

Affinity Mapping

Persona Creation

Empathy Mapping

03 - design

Divergent Design
Ideas (3)


Paper Prototyping

Feedback Session 1


Feedback Session 2

Prototype Design

04 - evaluate

Expert Evaluation

User-based Testing

Design Recommendations


Research Methods


Competitive Analysis




User Interviews (4)

Competitive Analysis

Because ISZ is a new technology, there are almost none direct competitors. However, there are some indirect competitor products that support some similar tasks of sound interaction outside the car environment.

Why did we conduct competitor analysis?

Shared audio spaces is a relatively new technology, with few companies doing what Harman is achieving. There are several existing services that support shared audio spaces, and they do share some conventional design. We used these services as references for when we create our visual design system.

Survey & User Interviews


141 Responses


4 in-depth semi-structured interviews

For our survey, we recieved 141 responses. Getting survey results ensured that we have a large enough representation of our target audience. All the survey questions were multiple choice based, which would lead to predefined answers. In order to get in-depth research insights, we conducted 4 in-depth semi-structured interviews. These interviews were conducted virtually and lasted around an hour long. We used Affinity Modelling to analyze the interview data.

Why did we conduct surveys & user interviews?

We conducted the surveys to understand the breadth of the problem space, demographic information and driver/passenger details such as family members, typical commute times, audio preferences etc. All the survey questions were multiple choice based, which would lead to predefined answers.

We conducted the interviews to get in-depth research insights. We followed a semi-structured interview method because it was also crucial for us to understand the context of the car as a shared media space for families. While we knew some of the questions that we wanted to ask, we also wanted to empower our research participants to share their stories and experiences.

Key Research Findings

Personal devices are preferred over the infotainment system

88 percent of respondents found their infotainment system is difficult to use and that they would use their personal devices instead. One interviewee mentioned that between the two options, he would still choose to listen to podcasts through his iPhone.
Implication: Personal devices must be integrated in the audio experience

Sharing music is a bonding experience

Many participants mentioned that driving with family & friends is a bonding experience, they often talk or share their favourite music with each other. One interviewee mentioned that playing music or radio gets in the way of communicating with each other.
Implication: ISZ must also empower the human urge to connect / have conversation.

Listening preferences in families vary a lot

Due to the variance in age, family members' listening preferences do not match. This often leads to some members sacrificing their preference for the others' preferences. One interviewee, a mother of two young children mentioned that she almost never gets to play her favourite music - it's either songs for the kids or her a podcast when her husband is with her.
Implication: ISZ is very useful in family scenarios.

"Screens exist but I don't want to look at them too much"

We found that most users have accepted touchscreens as a default part of the car they own. However, they expressed concern about being distracted when they have to navigate it and a simple task requires too many steps.
Implication: ISZ must be incorporated in the current system existing in cars but must have minimal steps required in every feature for it to be successfully adopted by the users.

Personas & Empathy Maps

Using the data from our interviews and contextual inquiries, we were able to present to our stakeholders the 3 distinct types of users involved in this problem and efficiently summarize their needs and goals. We used these personas when designing to ensure that our solution looped back to the needs and goals outlined in them.

Empathy Maps
Using the data from our interviews and contextual inquiries, we were able to present to our stakeholders the 3 distinct types of users involved in this problem and efficiently summarize their needs and goals. We used these personas when designing to ensure that our solution looped back to the needs and goals outlined in them.


For the ideation phase, we created three divergent design concepts. Each concept integrates ISZ with the physical space of a car in a unique way. We then tested these prototypes with user tests, iterations and more feedback sessions.

Divergent Design

3 concepts

User Test I

4 users

Wireframe I

First Iteration

User Test II

3 users

Wireframe II

Second Iteration

Divergent Design (Low-Fidelity)

Concept 1 - Screen based
- An interactive screen for each backseat passenger
- Front seat passenger and the driver are designed to share the same screen, considering the fact that the driver may ask the front seat passenger for assistance

Concept 2 - Physical buttons
- Physical buttons on the door handles as well as on the steering wheel to indicate ISZ Controls
- Easy Connectivity: Tap the phone on a physical sensor in front of their seat to get connected to that ISZ

Concept 3 - Share bubble
- Emulating interactions to maintain a bonding experience for the users
- Drag Bubble Interaction: To share content from one sound zone to another.


We conducted these two evaluation tests with two different groups of users. To emulate the physical space of a car as much as possible, we conducted one of the evaluation tests in Georgia Tech's Industrial Design Lab. We used paper prototypes, digital prototypes & printed prototypes for these evaluation rounds. Since these were conducted in person in a closed environment, it was difficult to recruit families - due to the pandemic.

Wireframes (Mid-Fidelity)

From the feedback we received from our evaluation sessions, our users preferred a combination of the Concept 1 (screen based ISZ) & Concept 3 (sharing bubble interaction). We created our first set of mid-fidelity wireframes using this feedback.

Home - Front Seat

Private & Parent Mode

Media Sharing - Backseat

Request for Shared Media - Backseat

Sharing Media - Phone App



Method 1

Heuristic Evaluation with Experts

Method 2

Virtual User Walkthrough with SUS Survey

Heuristic Evaluation with Experts

Given our complex project space, we involved experts from the UX design industry as well as vehicle related industrial design. This way, we can have overall perspective on our designed system. We asked the experts to use Jakob Nielsen's 10 Usability Heuristics for the evaluation session.

Usability issues reported by the experts

Virtual User Walkthrough with SUS Survey

For this session, we had users that represented our target user group - family members including parents, and young drivers, who live in the US. These users have had sufficient experience interacting or playing media in their car. The mode of virtual walkthrough was a video that explains and walks the users through our designed system. We had to resort to virtual methods, because our users were not available to meet in person.

Our SUS score was a mean of 78. According to research, the average SUS score of 500 studies is 68. Implying that our designed system is doing a good job, but not excellent job.

Scene from the video walkthrough

User feedback and corresponding design implications


Roadmapping complex projects

When we started this project, we did not anticipate it's complexity. As we went through research, implications and incorporating them into our wireframes, we had to decide to leave out some ideas due to the time constraint. For instance, post feedback sessions, we noticed that voice commands would be extremely crucial to the driver's experience. However, given the time left, we could not go deep into designing for voice. I learnt that with projects that can have many possible outcomes, prototyping and evaluation stage is important and must be alotted sufficient time to accommodate iterations.

Research can reveal true user intentions

While Harman's product focus was on individualizing the listening experience in cars, our research revealed that most users (from families) look forward to sharing music and content with their family members when travelling in a car. This made us realise that we must focus on the sharing interaction - making it as seamless as possible and that users would want an easy way to turn off ISZ when not required.

UX is more than designing screen based solutions

Prior to beginning this project, we discussed as a group to be cognizant of ensuring that our design decisions include the physical space of the car and not just the user and a screen that would be in front of them. To ensure this, in the first phase of our project, we did not define our end deliverable as a screen based solution, so that we could be open to other ideas. This reflected in the research findings as well.