Felix' Blog » Personal

Vuvuzela Filter using Fedora

Felix Kaechele — Sun, 13 Jun 2010 16:28:48 +0000

If you, like me, like to watch the world cup in South Africa but hate the monotonous sound of the so called Vuvuzelas this post is for you.

I will show you how to filter out the noise using your Fedora machine:

First we need to install the necessary tools and add ourselves to the jackuser group:

yum install jack-rack qjackctl pulseaudio-module-jack ladspa-swh-plugins
gpasswd -a felix jackuser

Of course these commands need to be run as root and you need to replace felix with your username. After you’re done with that you need to log off for the changes to become effective.

Now launch QJackctl from the Applications menu and start configuring it. The following screenshots show my settings. The don’t necessarily need to be your settings, so this is a little bit trial and error.

After you changed the settings you can start the Jack daemon by pressing “Start” in the QJackctl window.

Now you fire up Jack-Rack from the Applications Menu as well. For anything to happen with your audio within Jack-Rack you need to connect your audio devices to the Jack connection of Jack-Rack. This can be done using QJackctl. See below screenshot on how I connected Jack-Rack with my sound devices:

And finally you need to add the filters to Jack-Rack. I used a serial setup of four “Mag’s Notch Filter”. You can add them by clicking on the “+” button at the top left of the Jack-Rack window. Then go to Frequency -> Filters -> Notch -> Mag’s Notch Filter.

Here’s a screenshot of my filter settings:

Frequencies are 233, 466, 932 and 1864 Hz.

Kudos for the information on frequencies go to Surfpoeten.de.

Now you need to hook up the sound output of your TV or cable/sattelite receiver to your computer’s audio input and in turn connect your computer’s audio output to some speakers or headphones.

I usually leave both filters at the end of the rack disabled as that allows for more atmosphere while keeping the vuvuzelas down

It’s not perfect but seems to work okay. If you manage to tweak your setup to achive a better sound feel free to add your findings to the comments.

And now enjoy the next world cup game without those annoying vuvuzelas

Edit

Here’s a command line for mplayer to achieve the same within mplayer:

mplayer -af pan=1:0.5:0.5,sinesuppress=233:0.01,sinesuppress=466:0.01,sinesuppress=932:0.01,sinesuppress=1864:0.01,sinesuppress=232:0.01,sinesuppress=465:0.01,sinesuppress=931:0.01,sinesuppress=1863:0.01,sinesuppress=234:0.01,sinesuppress=467:0.01,sinesuppress=933:0.01,sinesuppress=1865:0.01

Found by Thomas Moschny at http://pastebin.com/KunkS0uk

Music that makes me happy

Felix Kaechele — Tue, 17 Feb 2009 22:42:22 +0000

Mr. Moix you totally made my day by pointing me to ELO – Mr. Blue Sky. That song is somewhat in the category “heard it in the radio, liked it, but never further investigated”
It’s been a pretty tough day today. First there was the preliminary “Abitur” (kinda like A-level) computer science exam at school today which was pretty exhausting since it took me the full 4,25 hours to complete. Second I had sports lessons after that Third I had a performance at music school today. We have a annual performance which this year happened to be today (right after both “Vorabitur” exams) and I failed performing the song “Fever” by Michael Bublé since I only had like 4 days to learn it by heart (well not really since I had to study for the exams). So THAT was actually not music that made me happy.
However hearing ELO before writing the exam made me happy and lifted my mood.

So to actually answer your question: Here is the music which makes me happy:

Alphabeat – Fascination (for those who think that Katrina & Waves is a bit outdated)
Marillion – Heart of Lothian: I. Wide Boy – II. Curtain Call
Jason Mraz – Dreamlife of Rand McNally
Mono & Nikitaman – Seid ihr bereit (I’ve seen them live and it was really good )
Leftfield – Melt (while this isn’t really uplifting I like to relax to this one)
Mike Oldfield – On Horseback (I find that to be very consoling)

This are just some I randomly came up with. There are probably so much more but I’m really interested in what Planet comes up with.

New GPG key

Felix Kaechele — Tue, 17 Feb 2009 13:22:39 +0000

I’m currently thinking about having some business cards printed for my Ambassador activities. And as 1000 cards cost about as much as 500 I decided to have 1000 cards printed
However when it came to putting my GPG Key on the card I noticed that my GPG Key will expire in 2010. I assumed I wouldn’t be that fast in handing out 1000 business cards so I generated a new GPG Key:

GPG-Key-ID: 0xB30D8F7C
Fingerprint: 5BF1 4BEA D4A4 7987 C3DA DCA2 775F 7BD0 B30D 8F7C

That one will expire in 2014 which should be enough time My old key is revoked as of now.

New Blog and FOSDEM

Felix Kaechele — Mon, 09 Feb 2009 22:36:07 +0000

So I finally got around to create a blog as well. Until now I successfully resisted to have one since I usually hate writing stuff that no-one really reads. But I find that this blog can pretty well serve me as a nice place to keep notes to myself that might be considered useful for others.

The first thing to blog about is my visit to FOSDEM.
It was my first year at FOSDEM and I must say I really liked it. After meeting fellow Fedora Ambassadors at the FAD EMEA 2008 for the first time I now had the chance to meet even more of them. I really enjoyed meeting people of whom I only knew the name and what they did before. It’s always great to have a face with the name in your mind.

I arrived together with Christoph in Brussels-Midi on Friday and after we checked into the hotel we began making our way to the Beer Event. We started to “love” the city of Brussels for it’s layout and road design which at times can be really confusing. But we finally arrived at the beer event. I had some “Delirium Tremens” which were very good. The next morning I found out that mixing strong beer with absinthe is not a good thing to do. Unfortunately the headache lasted the whole day and so I wasn’t really fit on Saturday.

On Sunday I was feeling quite well again and stayed at the booth for quite some time talking to people and handing out swag. I also managed to attend Max’s talk and the FreeIPA Talk later on, which was quite interesting.

I’m pretty sure that I’ll be going to FOSDEM next year as well.