Introduction to abcdrums
Multicultural Mathematics
Dr. Rachel Hall

Abcdrums is a program written for my students by Dr. Adlai Waksman, who used to teach in the Computer Science Department at SJU.  It is designed to produce MIDI files that can be played by most computers.  The general idea is to use what we learned about patterns in class to write drum compositions.

Open abcdrums

Step One:  Patterns.

Patterns are combinations of drum hits and rests.  In abcdrums, notes are indicated by "d" and rests by "z."  For example, the pattern

dzzdzzdz

sounds like

hit rest rest hit rest rest hit rest

This pattern is 8 beats long---remember that when we count beats we're counting both hits and rests.

Each pattern is called by a letter.  For example, we could call the pattern dzzdzzdz "Pattern A."  Scroll down the page to "Define a pattern" and type dzzdzzdz for Pattern A.  Now, we need to tell one of the drums to play Pattern A.  Scroll up to "Choose an instrument..." and choose Ride Bell from the menu.  Type A16 in the Ride Bell's box.  This tells the Ride Bell to play Pattern A 16 times.  If you go to the text box on the bottom of the page, you should see the following text:

% (Automatically generated by Abcdrums)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%>>% Voice 1:  Ride Bell  %%  127  %%  A16
%>>% Pattern A:  dzzdzzdz
%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Go to the bottom of the page and click on "Submit to ABC Convert-O-Matic." This sends your composition to a web site that makes MIDI files.  Clicking on the MIDI button should play the drum for you.  In the computer lab, you will have to right-click and save the MIDI file on the Desktop, then open it from the Desktop.

Step Two: Adding more voices.

Abcdrums allows up to 12 drums to play at once!  Let's keep Pattern A, and define

Pattern B: dzzzdzzz
Pattern C: dddddddd
Pattern D: zzdzzddz

Now choose some instruments (keep the Ride Bell as Voice 1) and assign them patterns:

Voice 2: Low Floor Tom   B16
Voice 3: Closed Hi-Hat   C16
Voice 4: Cowbell         D16

You should see

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%>>% Voice 1:  Ride Bell  %%  127  %%  A16
%>>% Voice 2:  Low Floor Tom  %%  127  %%  B16
%>>% Voice 3:  Closed Hi-Hat  %%  127  %%  C16
%>>% Voice 4:  Cowbell  %%  127  %%  D16
%>>% Pattern A:  dzzdzzdz
%>>% Pattern B:  dzzzdzzz
%>>% Pattern C:  dddddddd
%>>% Pattern D:  zzdzzddz
%%%%%%%%%%%%%%%%%%%%%%%%%%%%

in the text box.  This is an example of a CYCLE of length 8 beats.  Let's hear how it sounds!  Submit it to Convert-O-Matic and listen to the MIDI file...

Step Three:  Compositions.

Abcdrums allows you to use patterns to write lengthy compositions.  Instead of typing each pattern in every time you want to use it, you can give each voice instructions on which pattern to play when.  For example, keep the same patterns we've defined already, but change what each voice plays:

Voice 1: Ride Bell       A4 B4 A2 B2 A B A B
Voice 2: Low Floor Tom   B4 A4 B2 A2 B A B A
Voice 3: Closed Hi-Hat   C16
Voice 4: Cowbell         A8 D8

One of the few hard-and-fast rules is that each voice must contain the same number of beats. Remember that beats can be either hits or rests.  In this example, each drum plays 8 x 16 = 128 beats.  You should notice some interesting symmetries between the Ride Bell and the Low Floor Tom.  This pattern is called "trading 4s," "trading 2s," and "trading 1s."

Can I write melodies with abcdrums?  Some students have asked me about writing melodies with abcdrums.  It's possible (you choose Melody as one or more of the drum sounds), but I'm not going to go over it in class.  However, if you have some musical training, ask me about it and I'll show you.  You'll need to know the names of the notes and type them in as patterns.