My role

UX Design

Project type

Full time



What is Traktor Kontrol S4?

Traktor Kontrol S4 is a Dj hardware controller that lets you connect with your tracks using motorized haptic jog wheels that spin and react to nudging, scratching, pitch-fading, and backspins.

more about the development of this project below

Team setup

I led the efforts on the UX side from the very beginning. 

Stage 1 – The kickoff
Small exploration team, 1 designer (myself) and 1 product owner.

Stage 2 – The pivot
The Incubator. The team grow to 4 people.

Stage 3 – The actual development
A fully functional development team was set up. The setup included 1 Product Owner, 1 UX designer (myself), 1 industrial designer, 1 CAD engineer, 1 mechanical engineer and 1 electrical engineer.

What I contributed to this project

Planning & Coordination

I prioritized the research tasks together with the product owner balancing the customer expectations with the business needs. I reached to other teams and synced with other departments for coordinating our work in order to avoid double efforts.

Concept & Ideation

I created new concepts based on user input, both on my own and also in brainstorming sessions with my team. For better communicating the new ideas I created prototypes (cardboard to 3D renders to interactive).

User Research & Insights

I have organized user research sessions in various locations gathering user feedback both in person or remotely. I partnered together with other product owners and other UX and UI designers for executing the research rounds and I led synthesizing sessions.

Validation & Sharing

I validated the newly created concepts both internally with the team, and externally with the users. Shared the findings within the company by presenting to various internal stakeholders and documented the results.

Stage 1 – The kickoff

“create the next STEMS controller and improve on the design of the Kontrol S5.”

Initial challenge

Our challenge was to create the next STEMS controller. The goal was to push the innovation even further by offering unprecedented sound control to every DJ around the world.

What are STEMS

Music stems are a type of audio file that breaks down a complete track into individual mixes.

Business needs

Traktor was betting on STEMS. The previous DJ controller, Kontrol S8, was designed for STEMS so our challenge was to create the next STEMS controller. The goal was to push the innovation even further by offering unprecedented sound control to every DJ around the world.

User needs

I started gathering user feedback and expectations from forums and blogs. This allowed me to make a point towards user testing jog wheels. Internally there was the belief that we should build a controller without jog wheels but externally the users were complaining about this decision everywhere.

First user insights

After running the first user tests the data allowed me to make a point for redefining the challenge scope based also on user needs. Here are some of the learnings from the initial test.

Manual beat-matching is essential for DJ-ing and sometimes a life-saver

Jog wheels are used for more functions than just beat-matching

Manual beatmatching needs a jogwheel and a pitch fader as a unit

Touch-strips do not have proper tactile feedback and are INACCURATE

Stage 2 – The redefined challenge

“Design a new hardware that brings unique value to the market.”

“User first” approach

The clear user feedback made it possible to redefine the challenge. We started anew with a clean slate that could be defined by our users. Together with the product owner we managed to convince our internal stakeholders about the importance of having a “user first” approach.

Using “Design Thinking”.

I convinced the stakeholders to include this project in the new incubation effort that the company just started. It was also an ideal candidate for using the Design Thinking framework. We ran 3 complete cycles in 2 months.

First personas

Following the user interviews, we identified three main user groups/personas. Ir became clear that the first user group was the most numerous and demanding. If we manage to satisfy them, the product would be a success.


Uses his system controller only at home. He does not have any club gigs, but he is maybe doing small parties with his buddies.


Uses a system controller on stage only if he has to provide his own gear. He would rather prefer to take a USB stick instead.


Actually prefers to use a system controller when he goes to a gig. It gives him confort as this is the same hardware he uses at home to prepare.

Prioritising features with card sorting

I worked on finding out what would the users see as optional for this device.

Card sorting was the most efficient way to group the “must carry” features and also a good opportunity for gathering insights along the way.

For the remote interviews I resorted to Trello.

Testing possible device sizes

I got hands-on and I build a number of cardboard prototypes to mimic the real size and shape. To make it more realistic I worked together with our CAD engineer and 3D printed the jog wheels. The knobs and faders were simply glued to the surface.

This was the lowest effort needed in order to find the answer to our question about the device size.

Refining with co-creation sessions

I did a co-creation exercise using a puzzle game approach. The scope was to find out what is the most natural way to display informations and where is this information expected. For this I experimented with different layouts.

The results were quite a surprise for me and my team. I was expecting that users would simply go for the big screen. This wasn’t the case. It turned out that people would rather offload some of the information to the laptop in order to have a smaller hardware device.

Synthesising user insights

User interviews can generate a lot of data. It is important to extract the most important insights. Everything was shared with the team in synthesising sessions.

Proof of concept

Taking into account our finding regarding the way users expect information to be displayed we decided to build a proof of concept. I paired with our r&d developer for this and defined the visual feedback patterns that could be displayed on a LED ring around the jog wheel. I used it for further user testing. This helped a lot in defining the final look and feel of the product.

Stage 3 – The Actual Development

After the project was out of the incubation/exploration phase, in April 2016, the exploration team started the actual development process. A development team was formed the process went from a Design Thinking to a Lean UX model that was more suited for product development.

Features developed in this stage

I worked on the design of the effect units, haptic jog wheel interactions, sampler functionality and helped with BOM estimation.

The process

in order to further refine our product we use a Lean UX process that has cyclical phases.

  1. Prioritise and define (usually the responsibility of the product owner and UX)
  2. Communicate internally (product owner and UX designer)
  3. Build the prototypes (UX, CAD engineer or r&d engineer depending on the prototype)
  4. Recruit and test externally (UX with support from Customer Insights and sometime another available team member)
  5. Learn and communicate findings  (product owner together with the people involved in research)

Early 3D renders

In order to better visualize our product very early on in the process I also realized some 3D renderings.

What Worked Well

  • Talking to the user. Yes it can be time consuming and costly, but the cost of doing the wrong product is even higher. 
  • Involving the PO and even developers in the actual user interview process helped getting the buy-in for the concept and lowered the amount of design related meetings later in the process.
  • Recruiting people directly via facebook was effective as an emergency measure.
  • Getting out of the Berlin techno “bubble” was a good strategy. I conducted interviews all around the world remotely. I also organized face to face user sessions in the US.
  • UX designer acting like a communication HUB. Can be intense at times, but in the end it provided better alignment.

What Would I Do Differently

  • Isolating the project during exploration had two effects: the first one one was a speed-up of the design process. but the second one was a massive increase in the communication effort so that everyone is kept up to date with our progress. I would consider running the exploration phase inside the company even if it might be slower. 
  • Recruiting people could have been better handled by having a pool of users readily available
  • Considering the amount of effort it took to bring the industrial designer up to speed, I would consider involving him/her earlier in the process

The product