The LAC2014 Percussion Combo

A music box toy found in Rüdesheim
A music box toy found in Rüdesheim

At the Linux Audio Conference (LAC) 2015 in Mainz, I gave a small “lightning talk” on April 9th about a sound project that was started one year earlier, at the LAC in Karlsruhe in May 2014.

I recorded a couple of attendees creating various sounds outside a museum in Bruchsal, and later on converted these sounds into a sample collection that could – in theory – be used as a kind of percussion/drumkit.

The whole thing was rather more a joke than a serious project, but it was an interesting learning experience for me, lots of fun to create a “demo track” with it, and maybe someone finds this useful, so grab the kit here, and enjoy.

After recording, the main tasks were to cut out the individual sounds, trim them, add in tiny fade-in and fade-out segments (all of this was done with Sweep, a beautifully usable but unfortunately today little maintained sound file editor). Also, a bit of normalization or amplification/attenuation was done with very few of the samples. However, no compression or other effects were applied.

Most of the artists attempted to play their “instrument” with a kind of velocity layering (like, hitting a boot with another one first softer, then ever louder and stronger), but the order was not kept everywhere, so I also had to listen to the samples repeatedly to determine my own (purely subjective) correct velocity layer ordering.

Then I noticed that I created stereo samples, but this did not make so much sense for percussion instruments in a musical context, so I had to convert them to mono. On Linux, this is pretty much a 1-liner:

mkdir mono; for i in *.wav; do sox $i -c 1 mono/$i; done

The kit consists of 11 different “instruments”, some of which are velocity layered while others are best played as individual samples (one sample per key):

  • Lowa Boot Kick (Marc Groenewegen)
  • Banana Peel Slap (Pjotr Lasschuit)
  • Mini Stone HiHat (Frank Neumann, recorded much later)
  • Knee Bottle (Nils Gey)
  • Double Finger Snap (Bernard Tressol)
  • Rubber Band Twang (Michael Seeber)
  • Small hand Claps (Stefano Pedrinazzi)
  • Hand Fart (again Marc Groenewegen)
  • Ticket Key Rattle (Marie-Kristin Meier)
  • Camera Pocket Zipper (Fernando Lopez-Lezcano)

For each instrument you will find mono as well as the original stereo samples, in a “stereo/” subdirectory.
An .h2drumkit file for straight use with Hydrogen is included in the archive as well.

Here is a quick test pattern created in Hydrogen:

For those interested, the presentation was done with PinPoint ( Here is a plain rendered PDF version of those slides.

After the sample kit was done, I thought I’d also have to create “something real” with it – not just a quick test pattern – and after having had the initial idea of “doing a song that somehow shows the spirit of LAC”, I got carried faaar away and went wild in different aspects – writing a melody line, lyrics, arranging, creating a simple “video” (rather a slide show), and finally also – hold your breath – singing. Yes, really. And no, I cannot sing, but zita-at1 came to the rescue to fix the worst parts, and I think it did a great job :-).

The result is definitely not a masterpiece – it was done in a hurry, there was basically no mixing or EQing at all, but it was so much fun to create that I ignore the quality part here.

So, without further ado, I present the song/video that ended my lightning talk in Mainz – here is “That’s LAC” (video done with Blender’s VSE):

And this is what my screen looked like while working on this “jewel” –


I really start loving Qtractor and Calf Studio Gear. Oh, and setBfree is becoming ever better too!

(First) Linux Info Day in Ettlingen

On November 9th, the “Linux User Group Albtal” (LUG Albtal) which I am part
of held their first “Linux Infoday” in Ettlingen. While already having been founded 4.5 years ago, this was our first “public appearance”.

We manned a total of 6 “booths” with the topics “Linux in everyday life”,
“graphical desktops”, “virtualization”, “OpenStreetMap“, “Multimedia”,
“Games” and “Gimp“. Additionally, there was a PC for visitors to “fool around
with” so they get an idea of what Linux feels like, and some additional
systems hooked up to projector/TV to create some eyecatcher videos.

Visitors of the "Linux Infotag"
Visitors of the “Linux Infotag”

My booth was the “Multimedia” part, although it was really (obviously 😉
mostly about sound&audio applications. Setting up the gear took a little while, but was well spent – everything was at some point during that day.

My gear for the "Multimedia booth". I admit a 5-octave keyboard would have been better at times..
My gear for the “Multimedia booth”. I admit a 5-octave keyboard would have been better at times..

Since this was a first-time for us and we essentially had no budget at all,
we had no idea how much audience we would be able to attract. We did some
advertising through free newspapers in our region and distributing self-made
leaflets to local shops, but we already knew that this would not be seen by

Ok, so to sum it up already now: We had visitors, but it could have been more.
In total, there were perhaps 15-20 attendees across the whole day.

However, the individual “visits” were few but long (30 minutes, or even up to
one hour), so there was neither a feeling of being really bored, nor of
“having a queue waiting”. For now, we proved that we can put this up together,
which was good, and we might do a similar thing again next year, but we will
perhaps need some kind of sponsor to be able to do more advertising.

Still, for me personally the whole event was definitely a success – I had started
early to put together some “demo material”, and due to that I was kind of “forced”
to actually use some Linux audio software more than I would typically do.
While doing that, I discovered some new applications I had never used before, I
found updates of programs that had been rotting on my harddisk for a while,
and I found some programs to be a lot more stable than my past experience
had taught me.

Most prominently, qtractor as my main MIDI/audio sequencer application, has
really matured during the last 1-2 years since I was actually able to put
together a small radio play with it (audio tracks only) without seeing
qtractor crash on me a single time within 2-3 days of usage. Way to go, Rui! 🙂

Screenshot of qtractor while producing my first little radio play.
Screenshot of qtractor while producing my first little radio play.

The results of this work can be found below – but beware, it’s in German, and
there’s quite a bit of local gibberish in it. Inhabitants of Germany’s southwest
will easily recognize that I am not from around here (I am north-german
by birth), but I’ve tried to put in some Baden/swabian phrases that I learnt
since I moved here.

Sure, there are some weaknesses in there – pop sounds, cheap vocal performance – but it was big fun to put this together, and in the end that is still what counts most for me..for now.


So, bottom line is: While the event was not as much frequented as we had hoped,
I am perfectly fine with the results for now since I was able to establish a kind of
“workflow” for my own ideas, and that workflow proved to be pretty stable.
That means: The road is paved now for actually making music and producing a
first glass master ;^).


LAC2013: Roll The Drums!

Cat enjoying the warmth of a public terminal at the TU Graz

It’s just 2 more hours until LAC2013 (Linux Audio Conference #11) is finally starting. If you have no yet arrived in Graz by this time, better hurry up! Or, as an alternative, watch the video streams of the presentations from your comfy couch at home (URL should be available on the homepage soon now).

Yesterday’s “conference warm-up dinner” was already (as usual :-)) crowded with some (estimated) 40 folks in an italian restaurant, so it will be interesting to see much much audience there will be this year.

LAC’s up!


Back to ski business, finally!

Last year I was unable (due to my previous employer’s decision) to join some friends for skiing in Austria, so it was great I could go with them this year. We went to Kappl near Ischgl (one of Austria’s biggest ski resorts) in the Paznaun valley (Tyrol) from Feb 9th-16th with a group of 21 people in total, and had a house almost entirely on our own, booked through Interchalet.

First day, -18 degrees: Entering the "highway", Lattenalm
First day, -18 degrees: Entering the "highway", Lattenalm

The worst part of the whole week was getting there by car – not only was this a week of school holidays in our state (so, everybody and his children, aunt and grandmother drive to the Alps for skiing), but also we ran into several traffic jams due to fresh snow on the highway, blocked roads after acidents and more – which resulted in a total trip time of 11 hours for a 400km distance (normally it wouldn’t take longer than 5 hours). Ouch! I believe it cannot get much worse than this. I dreamt a lot of red brake lights that following night.

People sledge-riding at night on illuminated ski slope
People sledge-riding at night on illuminated ski slope

I believe I have never been out for skiing this early (when I was a child, with my parents we typically went around mid-March), so it was great to see that we really had snow all the way down to the valley, so all slopes back to town were possible without grassy or muddy areas. Also, the temperature was low enough to not let the snow age too soon (on the first day, we had -18C on the mountain tops). Only towards the end, the sun was able to kill a bit of snow.

Icicles on the ski lift, formed by rotational forces
Icicles on the ski lift, formed by rotational forces

Regarding a ski pass, one can choose between different models and areas (just Kappl, just Ischgl, “4 out of 6 days” and so on), but since I wanted maximum flexibility, I decided to go for the “access all areas” (See, Kappl, Ischgl, Galtr) pass for 6 days which costs a whopping 250. I didn’t regret that decision, though – we spent 3 days in Kappl, 2 in Ischgl and 1 in Galtr, and it was just cool to go wherever you just wanted to.


A chain coated by ice, at the Faulbrunn-Alm hut above Galtr

Weather was quite ok – there was one day of snow, one day of weak light, but 3 days with perfect conditions. Especially the day in Galtr (Wednesday) was great, with a very little bit of snow coming down all day long, making the air glitter and sparkle in beautiful ways.

Slight snow creating beautiful glitter in the air
Slight snow creating beautiful glitter in the air

On Thursday, I spent a couple of hours skiing on my own – I do this each time so then I can have a better eye on the landscape and making photos. Especially the highest point of the Ischgl ski arena, the Greitspitze (2871m) is a great place to overlook several mountain ranges and valleys.

Greitspitze, 2871m, highest peak in the Ischgl arena
Greitspitze, 2871m, highest peak in the Ischgl arena
Idalp, the most crowded place around Ischgl in winter
Idalp, the most crowded place around Ischgl in winter

Towards the end of that day, a friend on snowboard and me (just skis) got a chance to pick one of the last ski lifts up to Greitspitze at 4PM, and we suddenly found ourselves alone on the mountain – I love that moment. The sun was slowly setting, no noises around, just you and the snow. Those are great moments!

Time (and sun) running out on the last trip of a beautiful day in Ischgl
Time (and sun) running out on the last trip of a beautiful day in Ischgl

The last evening we traditionally do not cook, but go out for dinner instead – we went to “Hotel Post” in Kappl, and 4 of us ordered the “Postgeheimnis” together (due to a mistake by the waiter, we were actually served the dish for 5 persons – even better 🙂 which tasted great and was enough for..uhm..2 or 3 days :-).

Great dinner ("Postgeheimnis") on our last evening
Great dinner ("Postgeheimnis") on our last evening

To summarize: Bad start due to heavy traffic conditions, but thereafter a wonderful week with plenty of snow and great views. Luv it!

What’s left to be done is to use the videos I took with my GoPro HD Hero2 and “make something out of them”. I hope Blender will serve as a good video editing platform for this purpose.

Still picture from video shot with GoPro attached to ski stick, carried over my shoulder
Still picture from video shot with GoPro attached to ski stick, carried over my shoulder




High tide on the Rhine

High tide at the Rhine - "have a seat".

After quite a bit of snow and chill in the first weeks of 2013, last week has seen a dramatic temperature change – Wednesday we had +15C in and around Karlsruhe, which is quite unusual for this time of the year.

The mild weather caused heavy wind for a while, rain – and of course additionally a lot of melted water coming down from the Blackforest. The Rhine picks up these changes with a little delay, so today we seem to have reached the peak around 8m at Maxau.

Since the rain had finally stopped, I took the chance to go out for a little bicycle trip to the Rhine to see the water with my own eyes (and cameras) – yes, you can call me a “Gaffer” now :-).

How should the life guard ("DLRG") save lives when they can't reach their home base?

The water is already slowly retreating now, but this is certainly not something you see around here every day.

A swan enjoying its extended "hunting ground" - these are the meadows of the "Rheinstrandbad" (open air bath)

Hang Drum: An SFZ and a test

A friend recently pointed me at a french musician playing a short piece using a Hang Drum virtual instrument on a keyboard which sounded really nice. I immediately wanted to do “something like that” too, so I searched the web for some free Hang drum samples.

I found some at the web site of german composer and sound artist Andreas Bick.They sound a lot different from what I heard in the video mentioned above since Andreas is using soft mallets, but they were sampled pretty decently at 12 velocities per key.

Enhancing these with some SFZ config files for instant playability in LinuxSampler wasn’t too difficult, so here is an attempt at doing that. I provide 3 files, first one being just the original keys (no key ranges) and in mono, second being the same but spread out from E3 to A5 using ranges, and the third one is an attempt at making a “stereo” instrument by placing the samples in the -20..+20 pan range of LinuxSampler (which is really solved in a poor way since some samples’ range is just 1 note while others span a range of 7 or 8 semitones).




Simply place these in the same directory where the WAVs are stored, rename the files to end in “.sfz” so LinuxSampler/QSampler actually offers them for loading, and off you go.

Certainly, there must be a thousand things to improve (compensate for loudness differences between samples, better velocity mapping etc.). But this is how I learn – by simply doing it, waiting for the flame^H^H^H^H^Hfeedback and making it better the next time.

Here is a small experiment with this instrument. Using Qtractor as my weapon of choice for a MIDI/Audio sequencer, LinuxSampler, several LV2 plugins from the highly recommended Calf plugin suite. Bass played by a Yamaha P90, Shekere from the “Ethno World Library Vol.2” by Marcel Barsotti. I admit I got carried away a little with delay and chorus, but it was still fun :-).

Snow – the right time to go “bare foot”?

Yesterday, we finally had a bit of new snow all the way down to the Rhine valley which was followed by a few hours of sunny weather – ideal for a little walk outside.

Blades of grass under snow near "Kaisereiche"
Blades of grass under snow near "Kaisereiche"

On the same day, I received a parcel with a pair of “Five Fingers KSO” shoes that I had recently ordered. This is an experiment for me – I read lots of reports on “running shoes have too much damping” and “feet are not made for such shoes” and “we all should move back to natural running”. The Five Fingers attempt to give an “almost-barefoot” feeling to build up strength again in the foot strings and muscles that have lied dormant for too long. Of course, that whole process will take months or more, but I am not really in a hurry.

So, I was very interested to find out myself what it’s going to be like to walk and run in such “shoes”. I guess a cold Saturday with snow is not the ideal test bed for a first try, but I was curious, so I put them on and had a 5km walk through the snow. However, since I am a coward, I was cheating a bit: I did also wear toe socks.

Five Fingers KSO
Five Fingers KSO in snowy conditions

First finding: The “KSO” (“Keep things out” – they enclose the feet pretty tightly) are really not made for snowy/icy conditions. Walking up/down steep passages felt quite slippery. There are other products from Vibram that are better fit for such purposes, and I am now waiting for the snow to melt away again to test mine in better weather conditions :-). Still, I did not slip a single time – walking in such shoes makes you more careful where you put your feet.

Second finding: Although the KSOs really don’t give a lot of protection (the sole is some 3.5mm thick), stones or gravel were no problem at all. I certainly feel them when I step on them (that’s the whole idea – “feel connected to the ground below your feet”), but they do not hurt at all. I inspected my feet afterwards, and found not a single scratch.

Third finding, and this was a real surprise – it wasn’t cold at all. Although I spent around one hour at pretty cold conditions, there were only occasional feelings of “it might get a little chilly now”, but this went away after a few seconds. Back home, I checked the temperature of my toes, and they really didn’t feel cold at all. I believe these thin soles cause the feet to “work with the ground” so much that they have no chance to cool down – unlike normal shoes, where the feet don’t really have a lot of work to do. This was really encouraging since I sometimes do suffer a bit from cold toes.

Slippery, but not cold at all - they make your feet work!
Slippery, but not cold at all - makes your feet work

In general, I am now very much looking forward to gain more experience with these. One dream would be take them on a hiking trip in the Alps – I saw a young man doing that last year near Oberstdorf (in a high-alpine situation on a “Via Ferrata”), and he confirmed it feels pretty safe. I find that idea fascinating.


Hapi vs. Xylophone by GoldBaby – SFZ file

The kind folks at GoldBaby have released quite a few free sample sets on their webpage (but definitely also check out the stuff they sell for money!). One particular sample set that caught my attention is “Hapi vs. Xylophone”, a blend of two similar sounding instruments.

The download consists of a 55MB archive and holds 26 high-quality samples (44.1 KHz, 24bit – no velocity layers, though) plus configuration files for EXS24 and Kontakt. I have written a small config file for SFZ which works nicely for me in LinuxSampler (simply download the file, remove the “.txt” extension, and place the .sfz file in the same directory as the samples).

Here’s a quick sound example; pad sound is courtesy of Yoshimi.



Linux Audio Conference: Call for Papers’ deadline coming up

Capturing the spirit (and ambient sound) of the LAC2010 in Maynooth, Ireland

The next (11th) Linux Audio Conference – or LAC#11 for short – will take place at the IEM (Institute of Electronic Music and Acoustics) in Graz, Austria, from May 9th to 12th, 2013.

As every ear, the Call for Papers and Call for Music has been sent out a while back, and the deadline for paper and music submissions is on February 4th. If you plan to submit a paper, use the remaining weeks (and, likely, weekends) to grab the paper template, write your paper and put it into a good shape, and then hand it in through the LAC’s participation page.

The range of available topics is wide, so anyone should find something that his paper fits into. Especially “user-view” papers have always been accepted with great interest, as in “this is how I use application xyz to produce this kind of sound/music”, or “here is my workflow based on these tools”. Besides papers, proposing a workshop might also be an alternative if you’re not that much into writing papers.

The LAC has always been a great event, not only due to the high-profile content of the papers presented, but also due to its social factor (spontaneous hacking sessions, getting into contact with developers and composers, and generally having fun together).

Don’t miss it!