Raumfeld Controller



Android Development


Android, UPnP and streaming


Lautsprecher Teufel GmbH


2013 – 2018

What was Karlmax’s role in the project?

The app, the firmware and the hardware had been developed by Lautsprecher Teufel and already existed when the project began. We complemented the team and implemented various parts, for example a tablet version and various new features.

Why does the user need the app?

Because a Raumfeld system makes listening to music easier, nicer, and a whole lot more versatile.

What can the app do?

Raumfeld is an app-controlled multiroom streaming system for music.

The user gets to push different songs out to individual listening zones throughout the house. Maybe in the kitchen the radio’s always on in the mornings, but in the living room you have your own music going. Then again, sometimes you want the same music playing in all the rooms. No problem—it’s all controlled by the Raumfeld app.


The challenge

The challenge in this kind of system is handling the different data streams, and that multiple things need to be happening simultaneously in real time. The app doesn’t have the most difficult job here, since the handling of the stream happens in the hardware. However, all the components need to be constantly in communication with each other. The dependencies between firmware/hardware and software really come to light during the development of an app. And just as the hardware and software need to communicate clearly with each other, so too do the different teams working on the project. It’s all about the teams talking to each other. Just like if the app needs to be able to turn the Raumfeld speaker on and off, then the device has to both know this and be able to do it. It’s all about communication.

And because the client expects a flawless product, each version of the app goes through a careful test process until all bugs and flaws are taken care of. And even if high level automated test coverage is a challenge, we’ve learnt to appreciate this standard of care and accuracy.

How did we proceed?

We’ve been working with Raumfeld for a long time and have used various methods of cooperation, depending on the requested features or tasks. Depending on the project phase, the dependencies between different developers make it especially important to ensure close cooperation. That is where our years of working closely together really pay off. In the most recent phase we supported the teams which were responsible for implementing new features in the complex hardware/firmware/app layers. However, in other project phases it was maintenance work or taking over complete parts of the App. In the latter case there was less need to align with other members of the team, since individual work processes were more predominant.

Overall, through working together for so long, the processes became ever more efficient and productive. Using techniques such as joint code reviews with the developers from Raumfeld, high level automated test coverage and the early implementation of beta tests, it is rewarding to see how our teams work more and more closely over time.


Behind the scenes or: How I became a part-time DJ

I started working at Karlmax Berlin in April 2015. An intern at that time, the first project I worked on was Raumfeld. After that I’ve been a full-time developer on the Raumfeld app during my time at Karlmax Berlin. Music accompanies me all day, every day, which means it did for my colleagues as well. If you haven’t got a feel for the mood in the office, it doesn’t take long before you start getting evil looks. I can tell instinctively which song which colleague needs at any particular moment: whether one colleague needs a quick dose of Justin Timberlake to get their creative juices flowing, or if my co-developers need something a bit heavier to help them solve a bug. If I wasn’t predestined for this with my initials (M.C. Siegmund), then who is? As Nietzsche said, “Without music, life would be a mistake.”