One Soundcard to rule them all

The first sound card I got as an upgrade to a PC without sound back in 90s was the glorious Sound Blaster 16:

There were several different sound card options back in the days and all sounded a bit different.

sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces used for professional audio applications.


With the synthesizers and audio processing each series and make produced a distinctive sound. Some of us want to bring these sounds back. But keeping the (old) hardware running is an increasingly difficult task.

For example: The interface used by the above mentioned Sound Blaster 16 card is the ISA bus interface. This interface was introduced in 1981 and replaced in 1993. If you want to hear how such a sound card sounds today you would have to run hardware from this time period.

But some people are working towards getting at least some authentic sound back.

In this talk, Alan Hightower takes a look at the complexities, challenges, and even current progress at integrating all of the above cores into one FPGA based ISA sound card.

This is what the concept would bring if done:

Oh that would be soooooo nice to have all these vintage sound interfaces available and to be able to actually use them for audio output.

Experimental Audio Tool: SuperCollider

SuperCollider is a platform for audio synthesis and algorithmic composition, used by musicians, artists, and researchers working with sound. It is free and open source software available for Windows, macOS, and Linux.

SuperCollider features three major components:

scsynth, a real-time audio server, forms the core of the platform. It features 400+ unit generators (“UGens”) for analysis, synthesis, and processing.

sclang, an interpreted programming language. It is focused on sound, but not limited to any specific domain. sclang controls scsynth via Open Sound Control.

scide is an editor for sclang with an integrated help system.

Train Melody / 武蔵小杉駅

In hearing distance of the place I am usually staying when in Tokyo is a train station. So if the wind is right and the window is open I hear all these train station chimes and sounds.

If you don’t know what it is, let Wikipedia educate you:

train melody is a succession of musically expressive tones played when a train is arriving at or about to depart from a train station. As part of train passenger operations, a train melody includes a parade of single notes organized to follow each other rhythmically to form a lilting, singular musical thought.

In Japan, departing train melodies are arranged to invoke a relief feeling in a train passenger after sitting down and moving with the departing train. In contrast, arriving train melodies are configured to cause alertness, such as to help travelers shake off sleepiness experienced by morning commuters.


With this post I also want to have you hear what I mean. These sounds are having interesting pavlovian effects anyways.

before the train exits the station
played beforehand any announcement
doors are closing

Find more here and here and here.

Es ist egal, aber

Tocotronic is one of the bands I listened to during my teens/twenties. That dates me, that dates the band.

It’s very german. You’ll find their music on most streaming platforms. I recommend starting with the albums “wir kommen um uns zu beschweren” and “es ist egal aber”.

Anyhow. Now one member of the band starts a podcast!

Jan Müller ist seit über 25 Jahren Mitglied der Band Tocotronic. Er ist mit dem Format des Interviews bestens vertraut und kann sich als Fragender gut in die Perspektive seiner Gäste hineinversetzen. Die persönliche Auswahl seiner Gesprächspartner*innen bildet die Grundlage für authentische Gespräche, die stets von Interesse und Respekt geprägt sind. Mit “Reflektor” startet Jan seinen ersten Podcast.

train sounds in Japan

If you’ve ever been to Japan you must have noticed that everything and anything makes sounds and talks. Elevators, escalators, doors, train stations, gates, vending machines – you name it, it makes sounds and talks.

It’s so apparent but yet quite comforting that I enjoyed it. It became an additional channel of information without the need of point-and-call all the time. Highly effective for me.

Japan utilizes sounds to a degree that every detail seems to count. Take the station gates you rush through to get to your train platform. It’ll sound differently depending on how you pay, what status your ticket had and even how close your IC-cards balance is to being empty.

Or just the fact that the ticket gates make sounds at all to make you find them easily.

A good portion of this sounds you can find on places like YouTube or specialized websites. One of those specialized websites is

For some routes and stations you find here:

  • Station melody – departing and arrival melodies that are played on the occasion
  • In-car chime – chimes played before and after information broadcasts mainly in the Shinkansen and limited express trains.
  • Door opening and closing – doors make sounds too!

bringing the thinclient back

I had to solve a problem. The problem was that I did not wanted to have the exact same session and screen shared across different work places/locations simultaneously. From looking at the same screen from a different floor to have the option to just walk over to the lab-desk solder some circuits together and have the very same documents opened already and set on the screens over there.

One option was to use a tablet or notebook and carry it around. But this would not solve the need to have the screen content displayed on several screens simultaneously.

Also I did not want to rely on the computing power of a notebook / tablet alone. Of course those would get more powerful over time. But each step would mean I would have to purchase a new one.

Then in a move of desperation I remembered the “old days” when ThinClients used to be the new-kid in town. And then I tried something:

I just recently had moved all house server infrastructure over to Linux and Docker. So what would keep me from utilizing the computing power of that one beefy server in the basement to host all of my desktop needs?

It turns out: Nothing really. Docker is well prepared to host desktop environments. With a bit of tweaking and TigerVNC Xvnc I was able to pre-configure the most current Ubuntu to start my preferred Mate desktop environment in a container and expose it through VNC.

If you wanted to replicate this I would recommend this repository as a starting point.

Even better I found that the RaspberryPi single board computers come with a free pre-licensed and accelerated version of RealVNC.

So I took one of those RaspberryPis, booted up the Raspbian Desktop lite and connected to the dockers VNC port. It all worked just like that.

this is the RaspberryPi client with the windowed docker container VNC session

The screenshot above holds an additional information for you. I wanted sound! Video works smooth up to a certain size of the moving video – after all those RaspberryPis only come with sub Gbit/s wired networking. But to get sound working I had to add some additional steps.

First on the RaspberryPI that you want to output the sound to the speakers you need to install and set-up pulseaudio + paprefs. When you configure it to accept audio over the network you can then configure the client to do so.

In the docker container a simple command would then redirect all audio to the network:

pax11publish -e -S thinclient

Just replace “thinclient” with the ip or hostname of your RaspberryPI. After a restart Chrome started to play audio across the network through the speakers of the ThinClient.

Now all my screens got those RaspberryPIs attached to them and with Docker I can even run as many desktop environments in parallel as I wish. And because VNC does not care about how many connections there are made to one session it means that I can have all workplaces across the house connected to the same screen seeing the same content at the same time.

And yes: The UI and overall feel is silky smooth. And since VNC adapts to some extend to the available bandwidth by changing the quality of the image even across the internet the VNC sessions are very much useable. Given that there’s only 1 port for video and 1 port for audio it’s even possible to tunnel those sessions across to anywhere you might need them.

active noise cancellation does not suck on your eardrums

If you ever traveled on a train or plane with good active noise cancellation headphones you might agree how much more pleasant the trip was with much less noise reaching your ears.

When I tried active noise cancellation for the first time I had that weird sensation as if the pressure around suddenly changed. Like being in a very fast elevator or going for a quick dive. It felt weird but luckily it went away and the aww of joy replaced it. Quietness. Bliss.

Now there seem to be people for whom that feeling won’t go away. They get headaches and cannot stand the feeling when using active noise cancellation.

I’ve never had any explanation to this phenomena – until now. I ran across an article on SoundStage describing that in fact the feeling is not caused by actual changes of pressure but…

According to the engineer, eardrum suck, while it feels like a quick change in pressure, is psychosomatic. “There’s no actual pressure change. It’s caused by a disruption in the balance of sound you’re used to hearing,” he explained. 

eardrum suck – the mystery solved

Aha! The brain gets confused by signals reaching your ears that naturally would not exists. Those signals make no sense so the brain tries to make sense of it. And voilá something is sucking your ear drum!

Apple Airplay for SONOS (in Docker)

We’ve got a couple of SONOS based multi-room-audio zones in our house and with the newest generation of SONOS speakers you can get Apple Airplay. Fancy!

But the older hardware does not support Apple Airplay due to it’s limiting hardware. This is too bad.

So once again Docker and OpenSource + Reverse-Engineering come to the rescue.

AirConnect is a small but fancy tool that bridges SONOS and Chromecast to Airplay effortlessly. Just start and be done.

It works a treat and all of a sudden all those SONOS zones become Airplay devices.

There is also a nice dockerized version that I am using.

use case #3 – sonos auto bookmarker for audiobooks and podcasts

So you’re listening to this audio book for a while now, it’s quite long but really thrilling. In fact it’s too long for you to go through in one sitting. So you pause it and eventually listen to it on multiple devices.

We’ve got SONOS in our house and we’re using it extensively. Nice thing, all that connected goodness. It’s just short of some smart features. Like remembering where you paused and resuming a long audio book at the exact position you stopped the last time. Everytime you would play a different title it would reset the play-position and not remember where you where.

With some simple steps the house will know the state of all players it has. Not only SONOS but maybe also your VCR or Mediacenter (later use-case coming up!).

Putting together the strings and you get this:

Whenever there’s a title being played longer than 10 minutes and it’s paused or stopped the smart house will remember who, where and what has been played and the position you’ve been at.

Whenever that person then is resuming playback the house will know where to seek to. It’ll resume playback, on any system that is supported at that exact position.

Makes listening to these things just so much easier.

Bonus points for a mobile app that does the same thing but just on your phone. Park the car, go into the house, audiobook will continue playback, just now in the house instead of the car. The data is there, why not make use of it?

p.s.: big part of that I’ve opensourced years ago:

using the RaspberryPi to make all SONOS speakers support Apple Airplay

Airplay allows you to conveniently play music and videos over the air from your iOS or Mac OS X devices on remote speakers.

Since we just recently “migrated” almost all audio equipment in the house to SONOS multi-room audio we were missing a bit the convenience of just pushing a button on the iPad or iPhones to stream audio from those devices inside the household.

To retrofit the Airplay functionality there are two options I know of:

1: Get Airplay compatible hardware and connect it to a SONOS Input.

airportexpress_2012_back-285111You have to get Airplay hardware (like the Airport Express/Extreme,…) and attach it physically to one of the inputs of your SONOS Set-Up.  Typically you will need a SONOS Play:5 which has an analog input jack.


2: Set-Up a RaspberryPi with NodeJS + AirSonos as a software-only solution

You will need a stock RaspberryPi online in your home network. Of course this can run on virtually any other device or hardware that can run NodeJS. For the Pi setting it up is a fairly straight-forward process:

You start with a vanilla Raspbian Image. Update everything with:

sudo apt-get update

sudo apt-get upgrade

Then install NodeJS according to this short tutorial. To set-up the AirSonos software you will need to install additional avahi software. Especially this was needed for my install:

sudo apt-get install git-all libavahi-compat-libdnssd-dev

You then need to get the AirSonos software:

sudo npm install airsonos -g

After some minutes of wait time and hard work by the Pi you will be able to start AirSonos.

sudo airsonos

And it’ll come up with an enumeration of all active rooms.

Screen Shot 2014-06-25 at 11.38.47

And on all your devices it’ll show up like this:



Screen Shot 2014-06-25 at 12.38.27



I give you: the SONOS Audiobook / Podcast Auto Bookmarker – never lose your Listening Progress again…

Since the SONOS system I’ve bought turned out to be highly hackable I’ve spent some quality-time this weekend fixing the worst downside I’ve found so far that the SONOS system had for me

I am listening to a lot of Podcasts and Audiobooks. And it turns out that those two Genre are not particularly good supported by SONOS. When you’re listening to a 4 hour podcast and you stop it to play a song in between (since you stretch the listening of that podcast to several days) the next time you start that 4 hour podcast the SONOS system did not remember the position that you stopped at the last time and restarts the podcast from the beginning.

If you did not remember where you left of the last time, you’re lost. The same goes for Audiobooks.

Now this is the first feature I am teaching my SONOS system. And I am opensourcing it so you can do it as well.

SONOS Auto Bookmark Tool

Everything you need can be run on a RaspberryPi:

  1. You need NodeJS and node-sonos-http-api installed and running.
  2. You need MONO and sonos-auto-bookmarker (change the configuration.json file in bin/Debug after you xbuilded the .sln file)

Now the Auto Bookmarker Tool will, with the help of the sonos-http-api, monitor your household and whenever something longer than 10 minutes is played and stopped it bookmarks the last played position. Whenever you restart that track it will then seek to the last known position automatically.


Source 1:

Let the SONOS hacking begin!

I always wanted a networked multi-room audio solution as you can easily see here and here and here and here. Now it seems I’ve finally found something that integrates very well into our music listening habits and our infrastructure. And on top of that it turned out to be highly hackable.

I’ve went with SONOS for that multi-room solution. After trying two speakers for two rooms I’ve invested the budget into the full-house solution (not all speakers on below picture). And finally everything is as I always wanted.

Be warned: If you buy one speaker, you will definitly buy more.


So what’s in those boxes? Besides beautiful and high-quality speakers there’s a 250 Mhz linux powered computer inside each speaker. It got 64Mbytes of memory and wireless adapters to span it’s own wireless mesh network (hidden by default).

Each speaker on it’s own can be controlled and accessed through the SONOS controller applications (Windows/Mac/iOS/Android) or through several tools that open up new possibilities.

Screen Shot 2014-03-22 at 17.52.10

There will be more articles coming on the topic of hacking SONOS, adding functionality and using it for things not officially planned for by the manufacturer. Joy!


Source 1:

open source audio codecs getting better

Some weeks ago I heard about a new audio codec which is being developed as open source – very similar to vorbis – the previous open source approach to audio codecs.

This time it seems that they’ve got some standardization into the play so it might be more successful than vorbis was.

“Opus is a totally open, royalty-free, highly versatile audio codec. Opus is unmatched for interactive speech and music transmission over the Internet, but also intended for storage and streaming applications. It is standardized by the Internet Engineering Task Force (IETF) as RFC 6716 which incorporated technology from Skype’s SILK codec and Xiph.Org’s CELT codec.”

Source 1:
Source 2:
Source 3:

downloading the whole Jamendo catalog

Yesterday @simcup wrote on twitter about that he is currently downloading the whole Jamendo catalog of Creative Commons music. Capture

Although I already knew Jamendo it never occurred to be to download their whole catalog. Since I am a fan of choice I immediately thought about how I could download the catalog too. Since the only clue was a cryptic uri-like text how to achieve that it suddenly sounded like a great idea to write a universal tool and release it as open-source. This tool should allow users to download the whole catalog and keep their local jamendo mirror in sync with the server. So anytime new artists, albums or tracks are added the user does not need to download them all again.

So the only thing I had as a starting point was that cryptic uri pointing me to something I’ve never heard of called Rythmbox. Turns out that this is a GNOME music player application which has Jamendo integration. After some clueless poking around I decided to take a look at the source of Rythmbox, especially the Jamendo module.

This module is written in python and quite clean to read. And just by looking at the first lines I came across the interesting fact that there is a almost daily updated XML dump of the Jamendo catalog available from Jamendo. Hurray! Since Jamendo wants developers to interact with the platform they decided to put a documentation online which allows anyone to write tools and stream and download tracks. After all the clues I found I finally ended up on this page.

So there are the catalog download, track stream and torrent uris necessary to download the catalog. Now the only thing that is needed is a tool which parses the XML and creates a nice folder structure for us.


Parsing XML in C# (my prefered programming language) is easy. Basically you can use a tool called XSD.exe and let it generate first the XSD from the XML and then ready-to-use C# classes from that XSD.


After doing all that actually reading the whole catalog into a useable form breaks down to just three lines of code:


Isn’t it great how modern frameworks take away the complexity of such tasks. At this point I’ve already parsed the whole catalog into my tool and only wrote three lines of code. The rest was generated automatically for me. The best of all – this also works on non-windows operating systems when you use mono.

When the XML data is parsed and available in a nice data structure it’s easy to iterate through all artists, all albums and all tracks and then download the actual mp3 or ogg. And that’s basically what my tool does. It takes the XML, parses it, and downloads. It will check before downloading if the track already exists and will only download those added since the last run.

Additionally since I am deeply involved into the development of the GraphDB graph database at sones I want to make use of the Jamendo data and the graph structure it poses. Since the directory structure my tool is generating is only one aspect how you could possibly look at the data it’s quite interesting to demonstrate the capabilities of GraphDB based on that data.

The idea behind the graph representation of the data is that you could start from almost any starting point imaginable. No matter if you you start from a single track and drill up into genre and artists, or if you start at a location and drill down to tracks.

So what the Downloader does in matters of GraphDB integration is that it outputs a GraphQL script which can be imported into an instance of GraphDB.

The sourcecode of my tool is available on github and released unter the BSD license – feel free to play with it and to contribute.

Source 1:
Source 2:

Shairport – someone reversed an AirPort Express

Low Latency Network Audio was a dream for the past years (see an article of 2005 and 2008) and with AirPlay it’s finally there.

I am using the Apple AirPlay technology for several years now… after it got implemented into iOS it’s just fantastic to have the option to have whatever sound source I want to playing loud and clear in any room I want to…

Okay it’s not quite as sophisticated as the sonos solution regarding the control of multiple music sources in multiple rooms but it get’s the job done in an apartment.

So back to the topic: Apple integrated the AirPlay technology into their wireless base station “AirPort Express”. Basically AirPlay is a piece of software which receives an encrypted audio stream over the network and outputs the stream to the SPDIF or audio jack.

Back in 2005 there already was an emulator of this protocol called “Fairport” but Apple decided to encrypt the AirPlay traffic. This led to the problem that the encryption key was unkown because it’s baked into the AirPort Express firmware. And this is where the good news start:

“My girlfriend moved house, and her Airport Express no longer made it with her wireless access point. I figured it’d be easy to find an ApEx emulator – there are several open source apps out there to play to them. However, I was disappointed to find that Apple used a public-key crypto scheme, and there’s a private key hiding inside the ApEx. So I took it apart (I still have scars from opening the glued case!), dumped the ROM, and reverse engineered the keys out of it.”

So to keep things short: Someone got an AirPort Express, dumped the firmware, extracted the AirPlay encryption keys and wrote an emulator of the AirPlay protocol which uses the key. Voilá!

ShairPort is available in source code on the site of the guy and obviously it’s unsure if Apple will react by changing the encryption key in the future. But for the time being it works as advertised:

I took one of my computers and followed the instructions to update perl, install Macports and then run ShairPort. So when ShairPort is run it looks not as appealing as expected:

Notably  it uses IPv6 to communicate between iTunes and ShairPort… Oh I almost forgot to show how it looks in iTunes:

On another side note: It works on Linux, Windows and Mac OS X :-)

Source 1: Apple AirPlay
Source 2: Sonos
Source 3: Apple AirPort Express
Source 4: ShairPort

Still 9 days to go till SXSW 2010

Since there are still 9 days to go till SXSW 2010 it’s a pleasure to give out a link to the completely unofficial torrents which old all mp3 files of almost all songs which are to be presented at this years SXSW:

“The SXSW® Music and Media Conference showcases hundreds of musical acts from around the globe on over eighty stages in downtown Austin. By day, conference registrants do business in the SXSW® Trade Show in the Austin Convention Center and partake of a full agenda of informative, provocative panel discussions featuring hundreds of speakers of international stature.”


Source 1:
Source 2:

music of the weekend: Ladyhawke

Great find this weekend. I haven’t heard of Ladyhawke until Saturday. Now it’s the soundtrack of this weekend and the upcoming week!


Great pop music with a touch of rock. Powerful and fast. One of my favourites in the album is “My Delirium” – a song that has a subtle feeling of the Cardigans song “My Favourite Game”.

Ladyhawke writes in her blog about it:

“I wrote the song a year and a half ago after days of no sleep due to terrible jetlag. I felt like I was going out of my mind. I was missing my friends and family back home, and I was basically living to hear my phone ring in hope that it would be one of them calling. So my delirium came out of me thinking I was going crazy from lack of sleep!

I always knew this song had the potential for a really imaginative video, considering the general theme of the song is me going crazy. So when I read the treatment sent in by the Frater guys, a duo of London based directors who specialise inanimation, I knew it was the one!”



Es ist schon extrem erstaunlich was in einem vorgeht und welch erstauntes Gesicht man macht wenn man durch Zufall einmal ein Video von den Sprechern der “Drei Fragezeichen” findet.

Hand aufs Herz: Klingen die Stimmen so wie die Personen aussehen? Also ich komm immer wieder aus dem Staunen nicht heraus wenn ich die Stimmen höre und die Gesicher dazu sprechen sehe. Da muss doch ein Trick dabei sein!

Ach übrigends sind heute auch noch zwei neue Folgen der “drei Fragezeichen” erschienen…

taking Songbird for a spin (again)

Since my last Songbird experiences were not that great I thought it would be a great idea to take the newly released 1.2 version of Songbird for a spin.

It’s said that the new version is faster and more stable. I installed 3 hours ago and I still cannot use it since it’s syncing with iTunes ever since.


More on that topic when songbird is ready….