What you need
You can fill the card yourself with ‘sox’ and simple file commands. ‘sox’ can usually be installed with the package manager of your distribution.

The File System

Memory card format
The memory card must be formatted in FAT32 format. Our memory cards are delivered in this format. According to the specification, memory cards up to 32GB can be formatted with FAT32.

Folder structure and files on the card
In the root directory of the card, there must be folders named 0 to 8. Your audio files 0.WAV, 1.WAV, 2.WAV, etc., should be inside these folders. The file names determine the playback order in the playlist and start with 0.WAV (decimal zero).

hoerbert.xml
As long as you always convert the files yourself and copy them to the hörbert 2011 memory card, you do not have to worry about the hoerbert.xml file. This file is only used by the hörbert software for Mac and Windows. If it is not present, the hörbert software may create it itself if needed. Nonetheless, it is better not to delete the file because even an outdated hoerbert.xml file keeps the memory space free in case it needs to be updated in the future.

The Audio File Format

Converting your audio files
The audio files for hörbert 2011 must be in WAV format with a 32 KHz sample rate, 16-bit, mono. You can use the following command line for conversion with the ‘sox’ tool. The files that your ‘sox’ program can read depend on the compiled options.

sox --buffer 131072 --multi-threaded --no-glob inputFileName --clobber -r 32000 -b 16 -e signed-integer --no-glob outputFilename.WAV remix - gain -n -1.5 bass +1 loudness -1 pad 0 0 dither

Why not just copy directly?

Why can’t you simply copy mp3 files directly to the memory card for hörbert 2011?
Quite simply: So that you have to change batteries less frequently. Decoding mp3 files requires more processing power than playing WAV files. mp3 decoder chips sometimes require more power alone than what hörbert 2011 needs in total. If you run out of space, you can buy a larger memory card for little money, but then you will need to change batteries or recharge less frequently throughout the entire period of use.