Hello,

module A-113 offers only subharmonis in the range 1/1...1/24 derived from an
external VCO (e.g. A-111-3) and cannot be octave reduced. You find a
detailed desciption of the module on our website:

www.doepfer.com > English > PRODUCTS > A-100 > Module Overview > A-113

Best wishes
Dieter Doepfer

> For many years I have been interested in microtonal music. One of
> my favourite composers is Harry Partch who developed an
> intonational system that used 6 notes chords (hexads) derived
> from both the harmonic and subharmonic series. The harmonic
> chords were reduced into a span of a almost an octave and a half
> rather than the 4 octaves that the chords would have spanned if
> they were not octave reduced. If this does not make sense,
> Partch's otonal (harmonic series) chords had the following ratios
> 1/1, 5/4, 3/2, 7/4, (2/1), 9/4, 11/4. If this chord was not
> octave reduced it would have the following ratios (in ascending
> order) 1/1, 3/1, 5/1, 7/1, 9/1, 11/1. Partch also used
> subharmonic chords which he called utonal (from the word
> undertone). The utonal chords are mirror images of the otonal
> (from the word overtone) chords. For the mathematically inclined
> the ratios are in descending order 2/1, 8/5, 4/3, 8/7, (1/1),
> 16/9, 16/11. Again if these chords were not reduced to an octave
> and a half span they would have the following ratios (and
> different order): 1/1, 1/3, 1/5, 1/7, 1/9, 1/11.
> For more information regarding Partch's chordal structures see
> this page http://www.chrysalis-foundation.org/Partch-s_Diamond.htm
>
> I am sure you are wondering what this has to do with the Doepfer
> A-100 system Well, I currently use a Doepfer A-198
> Trautonium-Manual / Ribbon-Controller with a Tubbutec microtonal
> CV quantizer. I feed the quantized CV to an oscillator and then
> send the oscillator audio to an Erthenvar patch chord module
> which has an Equal Tempered, just intonation, and
> Harmonic/Subharmonic modes. I use an doepfer A-143-1 to a quad
> vca for creating arpeggios from the chord outputs. While this
> setup is good, I wish to have the freedom to choose the chordal
> mixes available and to change them during performance. I believe
> that the A-113 subharmonic generator module may be able to do
> this. Does this module only do subharmonics or are harmonics also
> available If the a-113 can only do subharmonics, can they be
> octave reduced Also is there a limit to the divisor (or
> multiplier if harmonics are possible). By this I mean is it
> possible to divide by 11, 13 or 17 etc
>
> If the subharmonics cannot be octave reduced then is there
> another way to do this Perhaps a precision adder or something could help
>
> Sorry for the long post
>
> Cheers,
>
> Justin
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