Category Archives: tech

building a home WFS system

I’ve been into spatial audio and especially Wave Field Synthesis, ever since my neighbor Simon Katzböck introduced me to the concept in Mörbisch, some years ago now. There, at the Seefestspiele, I was stunned to see how well it worked, how the voices seemed to originate from the singers, not the PA, and how realistic the LARES system there made the orchestra feel like it would in a concert hall. Mörbisch doesn’t feature a full fledged WFS installation, it’s more like a high order Ambisonics system that is quite unique and proprietary with a lot of fascinating technology supplied and programmed by the Fraunhofer Institute.

So, since no WFS installation is available in Vienna to play around with, I decided to build my own. I went for the minimum design first, to get some experience, and also to keep the cost (A/D converters especially) down. 16 channels would do for a first. I’m quite proud of how low I have been able to keep the costs till now. Here’s what I use:

  • 16 Visaton K50 speakers (250 Hz to 12kHz).
  • 8 2x 3W 5V powered amp boards fromSingapore, that I got on EBay (see photo below).
  • 2 8A 5V power supplies, also from Singapore, also source via EBay.
  • RME Multiface I that a friend lent me, for 8ch analog out, plus ADAT out.
  • Behringer UltraGain 8000 for additional 8ch.
  • a wood box with padding inside as a cabinet.

Total cost so far: less than 300€. I’m just assembling the whole shebang, and very excited to hear the first tones. On the software side I’m using PureData as a signal source and Marije Baalmans sWONDER WFS software for rendering.

Both are open source. PureData and SuperCollider will be running on my laptop (Lenovo X220 8GB i5, Win 7) and sWONDER on a Core2Quad PC with Debian 6 installed. Below some photos that I took so far, and as always, keeping you posted on the progress.

custom ROM for my HTC ChaCha pt2

So, after some fretting, and woeing why I hadn’t backed up my original ROM I finally got to the heart of the issue. The SuperDroid 1.0 ROM I installed on my ChaCha comes with A2SD baked in. A2SD or App2SD is a beautiful little app, that moves all of the apps to a ext3 partition on your SD, that you first create on with ClockworkMod (here’s a nice How-To). The problem here: my SD is a very, very cheap, very, very slow SanDisk microSDHC. So Apps like Messaging, Phone and so on take a very long time to load, making my phone very sluggish.

I deactivated A2SD with the GUI that you can download on Google Play and installed Link2SD, a beautiful tool that let’s you put programs on an ext3 partition of your SD and then creating symbolic links in Androids app directory. The advantage of partitioning your SD is, that, once you select the Disk Drive option when USB connecting, your phone only ejects the FAT32 partition of your SD card and not the ext3 partition, thus keeping all of your apps useable.

Now my phone is working really nicely, has lots of features it didn’t have before, like Titanium backup, or SSHDroid and AdFree. Next Step will be getting a fast SD card and then reactivating app2SD.

custom ROM for my HTC ChaCha

I really like my ChaCha, but one thing I got really fed up with is that it runs out of memory very often, so I can’t install some apps, like Instagramm or can’t update to the newest version of Google Maps. So after researching it a bit, I decided to install a custom ROM, SuperDroid, that would allow me to remove some of the built-in apps like Facebook and add a few others like Link2SD.

So I began, and altough my phone was S-ON, for whatever that means, which supposedly makes it more difficult to root it, I succeeded by doing this: (I exclude all the missteps and stepbacks, so it seems like one seamless, easy process, which, believe me, it was not)

  • Converted a microSD card to a gold card, so I can flash another version of the ROM, than the one, that I had.
  • Installed the newest HBoot from HTCs Dev site. (RUU_blabla.exe, before the actual unlocking begins)
  • Unlocked the Bootloader, as discribed in great detail on HTCs Dev site.
  • Installed CWM as described in this post, the XDA method failed me.
  • Installed my as described in same post.
  • Installed the SuperDroid ROM as described here.

So, I’ve been using it for a day now, and… IT COMPLETELY SUCKS!!! The phone is slow, drains battery, SMS take 2 minutes (yes that’s 120 seconds) to load, and contacts don’t display correctly!

Unfortunately it’s not easily possible to reinstall the stock ROM, since the HTC Rom Updater won’T flash, for security reasons. So, I’m currently searching for someone who was smart enough to backup their stock ROM before flashing.

Keeping you posted.