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Just Intonation ABC playre

01 Feb 01 - 03:32 AM (#387285)
Subject: Just Intonation ABC player
From: GUEST,Bruce O.

I just posted a bit on chords in the 'What is a chord' thread', and introduced just intonation there, based on the classical ratios between frequencies in major and minor (tirad) chords.

On my website is now an ABC player that will play tunes in ABC on either the just intonation scale or the 12TET one. [Note that for a tune not in C major | A minor you have to transpose, and some of the frequencies are usually different in the transposed key.] My ABC player doesn't have stored table of frequencies. It only has the two base notes stored; that for just intonation C (calculated from A=440) in octave 0 and that for 12TET C (A=440) in octave 0. While one note is being played the next is being calculated for the specified key/mode. My ABC player won't do double sharps or double flats (neither of which I've ever seen). That's trivial in 12TET, but in just intonation that takes 14 more notes. It's not hard to do, but hardly worth the effort.

My ABC player will also stressed note code the tunes, and figure out the mode# as described in file CODMTHD.TXT on my website.

My ABC player also has a J:specification, so you can avoid the ambibuity of the K:letter-mode spec. There are always 7 ways to get the correct number of sharps or flats on the key signature in an ABC, and you can score all tunes as locrian if you like. ABC doesn't care about correct key and modes, only the right number of sharps or flats on the key signature are required to play and display the tune correctly.

J:n# (or ^), or mb (or _), or 0 (zero) (n,m = 1-7) specifies the key sig. directly and by default takes the last note as key (or a much longer time duration note in front of it). This is correct most of the time, but in cases where there's a change of key in the tune it won't work. It's also poor for most circular modes and a disaster for a circular major that ends on the 7th of the scale, because that comes out locrian. In these cases just add the keynote you want after the number of sharps or flats. The program will tell you if you pick an impossible one [e.g., n# on the key signature with a keynote of Xflat]. See file USEABZ.TXT on my website for the syntax of J:spec. A J:spec over-rides the K:spec, but the program displays the original K:spec for comparison.

It's interesting to compare some frequencies. The 1st tune in Vol. I of Aird's 'Airs' on Jack Campin's website is "The Ranting Highlandman", better know as "The White Cockade". Jack has coded it as major mode with key = G, but the final is B, and it's a circular major mode (as my program will tell you, and it will tell you where the final is on the G scale). It can also (but not recommended) be scored as phrygian with key = B. There is a small difference in the two scales/mode combinations. Gmaj gives C=264 (the usual one), and key Bphrygian gives C=267.3, not much difference, but note that both scales give F#=371.25 rather than the F#=366.67 that we had in Cmajor | Aminor. Also, both have A=445.5 rather than the A=440 of the Cmajor | Aminor.


01 Feb 01 - 03:51 AM (#387292)
Subject: RE: Just Intonation ABC playre
From: English Jon

And where can we download this wonderous toy?

It's a great idea.

Regards, Jon


01 Feb 01 - 10:53 AM (#387465)
Subject: RE: Just Intonation ABC playre
From: GUEST,Bruce O.

My website is in Mudcat's Links


01 Feb 01 - 05:38 PM (#387796)
Subject: RE: Just Intonation ABC playre
From: Jeri

Here too:
01 Feb 01 - 07:07 PM (#387878)
Subject: RE: Just Intonation ABC playre
From: Malcolm Douglas

That would be:

Bruce Olson's Website

"This ought to be very interesting.  While I've heard music in just intonation, I can't "think" in it.   -Jeri"


01 Feb 01 - 07:22 PM (#387895)
Subject: RE: Just Intonation ABC playre
From: death by whisky

Could someone please explain what this is about?


02 Feb 01 - 05:53 PM (#388711)
Subject: RE: Just Intonation ABC playre
From: GUEST,Bruce O.

The ABC player has now been slightly upgraded. It will now accept J:Hp for highland bagpipe notation and give the true classical mode for the tune. 2 sharps on the key signature is the highland bagpipes only scale, but K:Hp fixes key-mode to A mixolydian, which seems to be correct for the majority of pipe tunes, but not for all.