doepfer
System A - 100
1. Introduction
Subharmonic Generator
A-113
A-113
Subharmonic Generator
1
Up
8.8.
Down
2
Up
8.8.
Down
3
Up
8.8.
Down
4
Up
8.8.
Down
Foot
Freq.
Ctr. 1
In
Attention ! The A-113 module requires an additional
+5V power supply with 100mA (e.g. the separate +5V
power supply or the +5V low-cost adapter)
Foot
Ctr. 2
Level
Out 1
Leve l
Out 2
Level
Out 3
Store
Level
Out 4
Preset
Mix
Out
Module A-113 (Subharmonic Generator) is an additional sound source that derives four independend
so-called Subharmonics from an incoming pulse signal. The module represents the sound generation
core of the
Sala (ref. chapter 6).
Subharmonic means in this context a sawtooth wave
whose frequency is derived from a master frequency.
The master frequency is divided by an integer 1...24 to
obtain the subharmonic. The subharmonics are available as 4 single outputs as well as mix output with
adjustable level for each subharmonic.
The integer
up/down buttons. The current divisors are displayed
with four 2-digit LED displays.
The combination of 4 divisors is called
mixtures form a preset. 50 presets can be stored and
called up within the module.
Two gate inputs are available to switch between the
4 mixtures within one preset (controlled by any gate
signals, e.g. from foot controllers).
Mixtur-Trautonium
divisor
for each subharmonic is set with
introduced by
mixture
Oskar
. 4
1
A-113
Subharmonic Generator
System A - 100
2. Basic principles
The Subharmonic Generator A-113 contains four times the following elements (see fig. 1)
• digital frequency divider (rectangle outputs) with
2-digit display and up/down buttons for divisor adjustment
• rectangle/sawtooth converter (with single output)
• attenuator controlling the amount (i.e. the ampli-
tude) of the subharmonic in the mix output
The incoming signal (preferably the rectangle ouput of
a VCO) is fed into the four frequency dividers. The
frequencies of the rectangle signals generated by the
frequency dividers are determined by the current divisors (1...24).
The rectangle outputs are converted to sawtooth waveforms by means of the rectangle/sawtooth converters.
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Fig. 1: Basic layout of the A-113
2
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System A - 100
Subharmonic Generator
A-113
Subharmonics
The
subharmonics
the frequency of the input signal.
The table in fig. 2 shows the frequencies and corresponding tone pitches of the resulting subharmonics
derived from an input signal with the tone pitch C
523,2 Hz).
Divisor Freq. [Hz]
1523,2C
2261,6C
3174,6F
4130,8C
5103,8As
687,3F
773,4D
865,4C
Fig. 2: Subharmonics of a signal with tone pitch C
result from
Note
5
4
3
3
2
2
2
2
integer division of
5
(i.e.
5
It becomes apparent that the subharmonics are equivalent to the tones of the
By way of contrast the
minor chord scale
harmonics
are equivalent to
.
the tones of the major chord scale. Harmonics are
integer multiples of the basic frequency (see fig. 3).
The undertone series (i.e. subharmonics) are the
mirror image of the overtone series (i.e. harmonics).
Factor Freq. [Hz]
165,4C
2130,8C
3196,0G
4261,6C
5329,6E
6392,0G
7466,1B
8523,2C
Fig. 3: Harmonics of a signal with tone pitch C
Note
2
3
3
4
4
4
4
5
2
3
A-113
H
Subharmonic Generator
The term "subharmonic" is not quite correct as
the A-113 outputs are sawtooth waveforms in
contrast to the sine waves used in the harmonics theory. A sawtooth wave has a marked
harmonic spectrum with odd and even overtones in contrast to the sine wave which is a
“pure” wave without overtones. For details concerning harmonic contents of different waveforms please refer to the A-110 or A-111
manual (VCO´s).
We wanted to use the same terms as Oscar
Sala in his Mixtur Trautonium and this is why
we call the outputs of the A-113 subharmonics
though they are sawtooth outputs.
System A - 100
Mixture
The combination of four subharmonics is called a
mixture. Four different mixtures ("00", "01", "10" und
"11") are available but only one mixture is active at a
time. The original Mixtur-Trautonium had only three
mixtures available but due to the binary structure of the
A-113 we introduced 4 mixtures.
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the volume foot controller are used to switch between
the 3 mixtures.
Preset
A preset consists of 4 mixtures with 4 divisors each
(see fig. 4). 50 presets can be stored and called up
within the A-113 module. The original MixturTrautonium had no presets available. Each mixture
had to be changed manually.
T1 T1 T1 T1
divisor
(display)
mixture
Fig. 4: Structure of a preset
T2 T2 T2 T2
T3 T3 T3 T3
T4 T4 T4 T4
"00" "01" "10" "11"
The active mixture is selected by the current state of
the two
Trautonium 2 foot switches mounted left and right of
4
gate control inputs
. In the original Mixtur-
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System A - 100
Subharmonic Generator
A-113
2. Overview
➃
➂
➁
➀
8.8
8.8
8.8
8.8
➅
➄
.
.
.
.
Divisor
Divisor
Divisor
Divisor
Store
Preset
A-113
Subharmonic Generator
Level
1
10
0
Level
2
10
0
Level
3
10
0
Level
4
10
0
SHG
Single
Out
Single
Out
Single
Out
Single
Out
Foot Ctr.
Foot Ctr.
Mix Out
In 1
In 2
Controls:
1 Display : displays the current divisor
Up
2
: button to increase the divisor
data
3 Down : same to decrease
Level : output level control (mix out-
4
➍
In
➊
➋
➌
➎
Preset
5
6 Store : preset store button
: preset selection button
In / Outputs:
! In : common audio input
Foot Ctr. 1
"
Foot Ctr. 2 : gate input 2 to switch bet-
§
Mix Out
%
$ Single Out : audio single output
put)
(rectangle input)
: gate input 1 to switch bet-
ween the mixtures
ween the mixtures
: audio mix output
5
A-113
Subharmonic Generator
System A - 100
doepfer
3. Controls
1 Display
This is the 2-digit LED display that shows the current
value of the divisor
In addition the
used to display the current mixture (see fig. 5):
decimal point is on:
• no
right decimal points are on: mixture "01"
•
• left decimal points are on: mixture "10"
• both
The mixture selected depends upon the states of the
two gate inputs $ und % (see chapter 4).
decimal points are on:
2 Up • 3 Down
The Up button 2 resp. the Down button 3 are used to
adjust the divisor (range
ding frequency divider.
.
decimal points
mixture "00"
to
01
01
0101
of the displays are
mixture "11"
) for the correspon-
24
24
2424
1
2
3
4
Fig. 5: Display of mixtures by means of decimal
1
2
3
4
points (from left to right: "00", "01", "10", "11")
1
2
3
4
1
2
3
4
H Before you adjust the divisors be sure that
you have selected the right mixture!
The Up/Down buttons of frequency divider 4 are
used for
if the preset button 5 is operated simultaneously.
4
The attenuators 4 control the amount of the
respective subharmonic present at the mix output
%.
preset selection
Level
instead of divisor adjstment
6
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System A - 100
5 Preset
While button 5 is operated one reaches the
mode (see chapter 2 concerning the term preset). In
this state the displays of the third and fourth frequency
divider show “Pr" resp. the number of the preset
currently selected (e.g. “45", see fig. 6a):
1
2
1
2
preset
(a) (b)
3
4
Fig. 6: (a): display of the current preset
(b): store preset with new preset number
To
select a new preset
of the fourth frequency divider are used while the
preset button 5 is operated until the desired preset
number appears in the fourth display.
As soon as the preset button 5 is released the module
returns to the normal mode. The displays show the
divisors of the new preset and the divisors can be
adjusted with the corresponding up/dow buttons.
the up/down buttons 2 and
3
4
3
Subharmonic Generator
A-113
6 Store
The store button 6 is used to store presets. The
following steps are required to store a new preset:
D Operate the preset button 5 and keep this button
pressed down (see fig. 6a).
The up/down buttons 2 and 3 are used to select
D
the preset number in which the current preset will
be stored (preset button 5 remains operated).
Pressing the store button 6 (preset button 5 still
D
remains operated) causes the storage of the current preset into the preset number selected. In the
upper displays appears "St" and "or" as confirmation of the storage process (see fig. 6b).
H
As soon as both buttons preset 5 and store 6 are
released the module returns to the normal mode. The
displays show the divisors and the divisors can be
adjusted with the corresponding up/dow buttons.
Pay attention not to select a preset number that already contains preset data you
may need in the future. Any former preset
data in the selected preset number are
deleted!
7
A-113
Subharmonic Generator
System A - 100
doepfer
4. In / Outputs
! In
Socket ! is the subharmonic generator’s audio input.
Connect up the signal you wish to use as master
frequency signal (normally the rectangle output of a
VCO).
" Foot Ctr. In 1 • § Foot Ctr. In 2
The gate inputs " and § are used to select the
mixture. Any gate type signals may be used (e.g. Foot
Controller, Sequencer gate outputs, MIDI interface)
(see fig. 7).
Foot Ctr.
In 1
00"00"
01"01"
10"10"
11"11"
Foot Ctr.
In 2
Mixture Display example
The mixture is displayed with the decimal points (see
chapter 3, fig. 5).
$ Single Out
Sockets " outputs the single subharmonic of the
respective frequency divider. The attenuators 4 do not
affect the level at these sockets.
% Mix Out
At output § the mix of the 4 subharmonics adjusted
with the 4 attenuators 4 is available.
Fig. 7: Selecting mixtures with gate signals
(0: gate = low or no gate signal applied,
1: gate = high)
8
doepfer
System A - 100
Subharmonic Generator
A-113
5. User Examples
Simulation of a Mixtur-Trautonium
The Trautonium is an electronic musical instrument
invented by Friedrich Trautwein in the thirties in Berlin,
Germany, with enhancements made by Oskar Sala in
the fifties which led to the well known MixturTrautonium. The Trautonium can be divided into two
logical sub-units: the control unit and the sound generation unit.
A detailed description of the Mixtur-Trautonium and
the realization with the A-100 modular system can be
found on our web site www.doepfer.com.
The replica of the Trautonium sound generation with
the A-100 presents itself as the A-113 contains all the
basic sound source elements of the Trautonium. The
Trautonium Format Filter A-104 completes the sound
generation as it is a copy of the lowpass/bandpass
arrangement of the Mixtur Trautonium. Only a few
A-100 standard modules (VCO, VCA, LFO, ADSR)
have to be added to obtain the typical Trautonium
sound.
A-113 as a complex sound source
A-113 in combination with a VCO makes available a
very complex and powerful sound source for a lot of
sound experiments. The four subharmonics generated
by the A-113 contain strong harmonic spectra with
even and odd harmonics. They represent ideal basic
sound sources to be modified with separate sound
processing modules.
Fig. 9 shows an example. "XYZ" represents any sound
processing combination of modules: e.g. VCF, VCA,
Phaser, Distortion, Ring Modulator, Vocoder, Frequency Shifter, Spring Reverb and so on with controlling modules like ADSR, LFO, Random, S&H, Theremin, Light-controlled CV, Joy Stick, MIDI interface and
so on. The controlling modules may be triggered or
synchronized (e.g. with a keyboard or sequencer controlled gate) or free running.
Fig. 8 shows the schematic construction of the Trautonium sound generation using A-100 modules.
9
A-113
Subharmonic Generator
System A - 100
Fig. 8 : Schematic construction of the Mixtur-
doepfer
Trautonium sound generation
(part 2 see next page)
10
doepfer
System A - 100
Subharmonic Generator
A-113
11
A-113
Subharmonic Generator
System A - 100
doepfer
A-113
SHG
Single
Out 1
VCO
4
Fig. 9: A-113 as a complex sound source
XYZ
MOD
Trig
A-135
VC-Mixer
Audio
In 1
ext . CV
In 1
Audio
Out
VCA
MOD
Trig
VCA
MOD
Trig
Mix
12
doepfer
System A - 100
7. Patch-Sheet
The following diagrams of the module can help you
recall your own Patches. They’re designed so that a
complete 19” rack of modules will fit onto an A4 sheet
of paper.
Photocopy this page, and cut out the pictures of this
and your other modules. You can then stick them
onto another piece of paper, and create a diagram of
your own system.
Make multiple copies of your composite diagram, and
use them for remembering good patches and set-ups.
P • Draw in patchleads with colored pens.
• Draw or write control settings in the little
white circles.
Subharmonic Generator
A-113
Subharmonic Generator
Divisor
8.8
8.8
8.8
8.8
Divisor
.
Divisor
.
Divisor
.
Divisor
.
Store
Preset
Level
1
Level
2
Level
3
Level
4
10
0
10
0
10
0
10
0
SHG
Single
Out
Single
Out
Single
Out
Single
Out
A-113
In
Foot Ctr.
In 1
Foot Ctr.
In 2
Mix Out
13
A-113
Subharmonic Generator
System A - 100
doepfer
14
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