How Surround Sound for Headphones Works

“That’s clearly left !”

3D hearing is a learned skill where your brain deducts the direction that a sound is coming from based on clues such as:


  • inter-ear timing differences Which ear does it reach first?
  • inter-ear volume differences Is it louder on the left ear?
  • frequency envelopes Is the signal lacking high frequencies?
  • reflections Was the signal reflected by your ear shell?

Low-flying Tie Fighter = Let’s Go Biking in Tuscany

Have you ever dreamed about being a tie-fighter pilot and flying through the death star at breakneck speed while dodging obstacles? I found the closest real-life equivalent: Going through tuscany on a racing bicycle.

  • map of my favorite bike routes
  • KML downloads
  • fancy pictures
  • accommodation & food recommendations

How to Backup Google Mail for Your Domain (Free + Open Source)

I’m currently migrating a company from using Google Mail to an Office 365 hosted exchange server. Before getting started, I wanted to make a full backup of all mails of all users. Now there’s several commercial offers and also several shady-looking free tools to accomplish this task, but I didn’t feel comfortable trusting either one. So I built a very simple free and open source solution.

Zoo-locked - Mutually Exclusive Task Execution Using ZooKeeper

I’m currently preparing the spratshop.com architecture for a truly distributed set-up with multi-master database replication and automatic load-balancing between the nodes. The spratshop system uses C++ and Java for the back-end services and Rails for the front-end. We have a set of rake tasks that run hourly or daily to monitor, maintain and clean up the system.

In the intended multi-node deployment, these rake tasks will still need to be executed, but I cannot pin them all to a single node because otherwise the system would break as soon as that node has problems. As such, the best way is to run these maintenance cronjobs on every node, to make sure they will continue to execute even when nodes fail.

It’s Finally Online !

I’ve had the first article for this blog lying around for close to a year now… and then life got in the way ;)

But today, I finally took the time to create a nice theme and get this blog online.