The Bell Definition File

The Bell Definition File

Abel uses a Bell Definition File to describe bell sounds and how to use them. These Bell Definition Files have to be in the Abel 3\Bells subdirectory (usually C:\Program Files\Abel 3\Bells) and have a .bdf file extension. Each file describes one particular bell 'sound' or 'character': each bell character might be made up of several recordings of different bells.

Abel manipulates sound samples to make the different notes: a single bell recording can thus be usd for several different bells. However, Abel can only stretch a sound so far before it starts to distort, so Abel uses several samples with different original pitches to make up the required range of notes for a bdf file.

You should bear this in mind when making your bell recordings: don't sample adjacent bells, but instead record bells that are reasonably far apart (for example, if you have 12 bells, you might sample the tenor, treble, 4 and 8, providing these bells have a good tone).

The Bell Definition File is a text file that you can edit in any text editor (eg, Windows Notepad). The safest way to make a new one is to copy one of the examples that came with Abel, and edit it to refer to your own bell samples.

Here is an example, described in more detail below:

# This is my sample Bell Definition file
BDF,Bells from somewhere
tbell_1.wav, 61, 72, 45
tbell_2.wav, 73, 90, 73

This Bell Definition File specifies two recorded bell samples, and the range of notes for which each sample is to be used.

It has the following format:

Comments can be inserted anywhere. They are introduced by a # and run to the end of the line.
Whitespace (tabs, spaces and new lines) is ignored. Comments are treated like whitespace.
The first non-whitespace characters must be the sequence "BDF,"
Following "BDF," is the text description of this bell sound. This text is what Abel will display when you choose a bell sound from the Options/Sound menu, so it is a good idea to choose something you will recognise easily.

After the description line there is a series of sound sample definitions. You can have any number of these, but anywhere from 1 to about 4 or 5 is typical.

Each sound sample definition line contains the filename of the sample. This file is located in the same directory as the Bell Definition File. After the filename is a sequence of numbers.
The first number is the MIDI note value of the original sound sample. Middle C in MIDI notation is ‘60', and the numbers go up or down by one for each semitone. So, for example, if your bell sounds the D above middle C, you would put ‘62' in as the original note value (2 semitones above middle C).
The second number is the MIDI note value of the HIGHEST note you want to use this sample for.
The third number is the MIDI note value of the LOWEST note you want to use this sample for.

So, the above example says that the sample tbell1.wav has an original note of 61 (middle C sharp), and we want to let Abel shift its frequence down as far as MIDI note 45 and up as far as MIDI note 72. For pitches above MIDI note 72, the second sample tbell2.wav is used.