About the music
01. Toccata and Fugue in D minor
Two 6581 chips.
The toccata is perhaps the most well-known work in the entire organ
repertoire. Like many toccatas, it is probably a transcribed improvisation. It
has been postulated that this was a test tune that Bach would play when trying
out new organs. That would explain its crude character and the various hops
between heavy chords and rapid melodic parts.
The fugue is written for four
voices, and the subject resembles a passage in the toccata.
02. Ich ruf' zu dir, Herr Jesu Christ
One 6581 chip.
This is a chorale prelude from Orgelbüchlein. The chorale itself is a
very simple melody, so the praxis is to embellish it with trills and other
ornaments. Thus, my interpretation will be different from other recordings you
may have heard.
This piece of music was featured in Tarkovsky's film Solaris.
03. Contrapunctus 1 from Die Kunst der Fuge
Two 8580 chips.
Die Kunst der Fuge is a terribly clever suite of fourteen fugues and four
canons, of increasing complexity, all based on the same theme. This is the
first piece in the suite, so it is a comparatively simple four-part fugue.
04. Allein Gott in der Höh' sei Ehr'
Two 6581 chips.
Bach has based at least ten different works on this melody (BWV numbers 662,
663, 664, 675, 676, 677, 711, 715, 716, 717), presumably quite varying in style
and harmonic content. This version is a chorale prelude.
05. Passacaglia and Fugue in C minor
Two 8580 chips.
The grand finale!
A passacaglia is based on a short melody which is repeated throughout the
piece, mostly in the bass, sometimes with variations. In classical music, this
type of prolonged repetition of a single theme is called an ostinato. In
contemporary music, it's not called anything at all, because it is implied.
The fugue is quite advanced. The subject is the first half of the ostinato
from the passacaglia. Everytime the subject sounds, two counter-subjects can
also be heard (except in the very beginning of the fugue), while the fourth
voice joins the others in free counterpoint. These four roles — playing
the subject, playing the first counter-subject, playing the second
counter-subject and playing free counterpoint — can be distributed among
the four voices in 24 different permutations. This happens eleven times
throughout the fugue, and Bach picks a different permutation every time
according to a mathematical formula. Can you find it?
About the technology
It struck me that, at least in theory, organ pipes should generate quite
primitive sound waves. If so, how come a church organ doesn't sound like a
chip tune, which is also built up from simple waveforms? Well, actually
it will, if you remove the church. And if you connect a
Commodore 64 home computer to a loudspeaker in a large hall, it will
sound like an organ.
So the music on this album is not performed on a pipe organ. Instead, what
you hear is the sound of one or two SID
chips (controlled by a Commodore 64), enhanced by a convolution reverb to
simulate church acoustics.
There is already an abundance of SID tunes based on sheet music, in
particular by J. S. Bach. The problem is that all those SID tunes are
terrible. Apparently, people have merely typed in the notes from the sheet
music. This leads to quantized timing (where e.g. every quarter note lasts
exactly 500 milliseconds, always), and while quantized timing may be
perfectly fine for modern genres, it simply won't do for classical
The goal is not to play the right notes in the right
order; that's the starting point. Then you have to adjust the timing of every
single note, listening and re-listening, making sure that it doesn't sound
mechanical. You have to add movement, energy, and emphasis (which, on an organ,
has to be implemented by varying the duration of the notes, and the pauses
between them, because there's no dynamic response). You need fermatas and
ornaments. You have to realize that some jumps cannot be performed unless the
organist lifts his hand, and so on, and so forth.
This album is an attempt to demonstrate that classical music can indeed be
performed by a computer. But the amount of work that goes into programming the
computer will never be less than the work that a traditional performer would
put into studying the same piece of music.
In general, I've opted for fixed-width pulse waves for the manual voices,
and a pulse hard-synced with a triangle wave one octave below for the pedal
voice. Some waveforms are run through a combined low-pass and band-pass filter
with moderate resonance. In Allein Gott and Ich ruf zu dir, I use a
narrow pulse wave for the cantus firmi and unfiltered triangle waves for the