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## Re: question about transposing an interval of a 4th

 From: James E. Bailey Subject: Re: question about transposing an interval of a 4th Date: Wed, 24 Dec 2008 14:24:15 +0100

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Am 24.12.2008 um 13:26 schrieb M Watts:

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```Tim Reeves wrote:
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> Umm... yeah.  The fact that he thinks this answers the question
> gives me *less* confidence that he knows what he's talking about.
> If he wanted it a perfect fourth lower, then \transpose does the
> job.  And normally when somebody says "a fourth lower", they mean
> a perfect interval.  If he wants it a variable fourth lower, then
> it's not doable without scheme.
>
> - Graham

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Yes, a variable fourth, if you want to call it that - you finally got it. This is like the not-so-helpful answer "You can't get there from here."
```It just took about 20 messages to get to that conclusion.
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Actually, there is a way, but it's just something to muck around with, and takes a lot longer than scrawling stuff by hand on a sheet of ms paper.
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Mididings, the python-based midi router from http://das.nasophon.de/ mididings/, includes a 'diatonic harmonizer', which allows you to add or substitute a harmony line at a specified interval from the notes being played, with respect to the home key.
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So you could:

2) save the following as test.py

# start of file
# harmonizer.py - example usage of the diatonic harmonizer
#

from mididings import *
from mididings.extra import Harmonize

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# substitute a fifth above each note played -- equivalent to a fourth below, this only works upwards --, based on the D Major scale
```run(
Harmonize('d', 'major', 'fifth')
)
# end of file

3) start Jack

4) run python ./test.py

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5) connect a (virtual) midi keyboard to mididings input; connect mididings output to a recorder or sequencer app capable of saving a midi file
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6) run midi2ly on the resulting file
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Merry Christmas!
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Ditto.
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Yeah, that's about what he actually did. Except he used sibelius instead of whatever free program you mention.
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