previous Tuning Digest # 1598 next

edited by Joe Monzo

From the Mills College Tuning Digest


From: tuning@onelist.com
To: Joe Monzo
Date: Tue, 1 Dec 1998 11:06:19 -0500 (EST)
Subject: TUNING digest 1598

TUNING Digest 1598

Topics covered in this issue include:

1) All, then best, 7-limit scales with 31 consonances
by Paul Hahn

2) Re: All, then best, 7-limit scales with 31 consonances
by Paul Hahn

3) Re: Corrections on my "What is a Wolf?"
by "M. Schulter"

4) Reply to Reinhard on Subharmonics
by "Paul H. Erlich"

5) Symmetry
by Carl Lumma

6) Re: Orpheus and the Undertones, Subharmonics, Utonalities etc.
by "Paul H. Erlich"

7) Lumma's challenge
by "Paul H. Erlich"

8) Re: Lumma's challenge
by Paul Hahn

9) Re: Lumma's challenge
by Paul Hahn

10) Finale xen-cidentals
by Harold Fortuin

11) Re: Lumma's challenge
by bram

----------------------------------------------------------------------

Topic No. 1

Date: Mon, 30 Nov 1998 10:28:37 -0600 (CST)
From: Paul Hahn
To: Tuning Digest
Subject: All, then best, 7-limit scales with 31 consonances
Message-ID:


           35:24-------35:16------105:64
         .-'/ \'-.   .-'/ \'-.   .-'/
      5:3--/---\--5:4--/---\-15:8  /
      /|\ /     \ /|\ /     \ /|  /
     / | /       \ | /       \ | /
    /  |/ \     / \|/ \     / \|/
   /  7:6---------7:4--------21:16
  /.-'   '-.\ /.-'   '-.\ /.-'
4:3---------1:1---------3:2

On Sat, 28 Nov 1998, Paul H. Erlich wrote [1595.10]:

[me:] By my count this has 31 7-limit consonances.
Guys, wouldn't any rotation and/or reflection of this figure in the tetrahedral/octahedral lattice work too?

There are twelve possible orientations for this shape in the 7-limit 3-d space, only three of which are Euler genuses (geni?). That does not, however, exhaust the possible scales which have 31 7-limit consonances. Those can be completely enumerated by butting up two hexanies against each other (six ways to do that) and then adding two "stellating" points/tetrads--that is, notes which form complete tetrads with one of the 12 exposed triangles (faces of the octahedra which are the hexanies). This gives 6 * 12 * 11 / 2 or 396 different scales. Unfortunately most of them are very uneven. There are only three whose smallest scale degree is not smaller than 25:24; they approximate 12TET reasonably well. This is the (IMHO) best one:


42:25------21:20-------21:16
   \'-.   .-'/ \'-.   .-'/ \'-.
    \  6:5--/---\--3:2--/---\-15:8
     \ /|\ /     \ /|\ /     \ /|
      \ | /       \ | /       \ |
     / \|/ \     / \|/ \     / \|
    /  7:5---------7:4--------35:32
   /.-'   '-.\ /.-'   '-.\ /.-'
 8:5---------1:1---------5:4

You can get the other two (a) by substituting 25:16 for 8:5, or (b) by inverting this one (which, transposed, can also be thought of as substituting 25:16 for 8:5 and 105:64 for 42:25). (a) is more symmetrical (same shape within the lattice as the original Euler genus) but has a diameter of 4, whereas this one and (b) have diameters of 3. Furthermore, the most complex (quaternary) interval in (a) is actually a scale step: 42:25 / 25:16 = 672:625. Yech!

--pH  http://library.wustl.edu/~manynote
    O
   /\        "'Jever take'n try to give an ironclad leave to
  -\-\-- o    yourself from a three-rail billiard shot?"

             NOTE: dehyphenate node to remove spamblock.          <*>

------------------------------

Topic No. 2

Date: Mon, 30 Nov 1998 10:47:09 -0600 (CST)
From: Paul Hahn
To: Tuning Digest
Subject: Re: All, then best, 7-limit scales with 31 consonances
Message-ID:

On Mon, 30 Nov 1998, Paul Hahn wrote:

There are only three whose smallest scale degree is not smaller than 25:24; they approximate 12TET reasonably well. This is the (IMHO) best one:

	 
	42:25------21:20-------21:16
	   \'-.   .-'/ \'-.   .-'/ \'-.
	    \  6:5--/---\--3:2--/---\-15:8
	     \ /|\ /     \ /|\ /     \ /|
	      \ | /       \ | /       \ |
	     / \|/ \     / \|/ \     / \|
	    /  7:5---------7:4--------35:32
	   /.-'   '-.\ /.-'   '-.\ /.-'
	 8:5---------1:1---------5:4
	
You can get the other two (a) by substituting 25:16 for 8:5, or (b) by inverting this one (which, transposed, can also be thought of as substituting 25:16 for 8:5 and 105:64 for 42:25).

OTOH, one way in which (a) has the advantage over this and (b) is that (a) is completely "covered" by its four tetrads, whereas the other two are not.

--pH  http://library.wustl.edu/~manynote
    O
   /\        "'Jever take'n try to give an ironclad leave to
  -\-\-- o    yourself from a three-rail billiard shot?"

             NOTE: dehyphenate node to remove spamblock.          <*>

------------------------------

Topic No. 3

Date: Mon, 30 Nov 1998 11:36:24 -0800 (PST)
From: "M. Schulter"
To: Tuning Digest
Subject: Re: Corrections on my "What is a Wolf?"
Message-ID:

Hello, there.

Having read over my "What is a Wolf?" article -- after posting, as Murphy's Law would have it -- I'd like to offer two important corrections, not to exclude more from other participants here.

First, I wonder if the following passage might have been a kind of intonational "Freudian slip" in one direction or another:

In tunings of the later 15th-17th centuries, we run into a different kind of "Wolf" complication: the fact that three pure major thirds of 5:4 or ~386.31 cents each do not add up to a pure 3:2 octave, but fall about 41.06 cents short.

Of course, a "pure octave" is usually regarded as being 2:1, not 3:2 (a pure fifth). Could I have been still focusing on Pythagorean tuning with its pure fifths (the topic of some previous paragraphs?), or possibly the just or tempered Bohlen-Pierce scale with its 3:1 "tritave" in place of the usual 2:1 octave?

My other error concerned an "augmented fifth" sonority found in 16th-17th century music, where I mistakenly gave the size of a minor sixth in 1/4-comma meantone tuning as ~890 cents (actually the size of a major sixth in this temperament) rather than the correct ~814 cents (a just 8:5, the octave complement of the just 5:4 on which this tuning is based).

Here is a corrected diagram showing the sizes in cents of intervals in the combination in question d-bb-f#', plus a diagram of the alternative d-bb-gb' showing the diminished fourth (or eleventh) between the outer voices. Note that I've inexactly rounded this diminished eleventh to 1628 cents in order to make the arithmetic look consistent, although the minor sixths d-bb and bb-gb' are actually about 813.69 cents each, and the diminished eleventh d-gb' thus roughly 1627.38 cents, closer to 1627 than to 1628:


    f#'         gb'
(1586,772)  (1628,814)
    bb          bb
  (814)       (814)
    d           d

Unfortunately, not only did I err here on the math, but spuriously suggested that adding a Gb key to a meantone keyboard would permit one to "avoid" the Wolf augmented fifth bb-f#' by replacing it with bb-gb'. While this "solution" would succeed with bb-gb' as a simple interval, changing d-bb-f#' to d-bb-gb' would replace the evocative bb-f#' between the upper voices of the first sonority with a diminished eleventh d-gb' between the outer voices, likely much less pleasing in this stylistic context.

Having fairly muddled this meantone example, maybe a few examples of how adding notes to the keyboard can solve certain Wolf problems might not be out of place. First, let's consider the case where a single extra note could resolve a Wolf diminished fourth:


      f#'          f#'
  (697,270)    (696,310)
      eb'          d#'
    (427)        (386)
      b            b

Here adding a D# key permits replacing the diminished fourth and augmented second of the first example with a regular major third and minor third in the second. As usual, I've taken liberties with the rounded value in cents for a 1/4-comma meantone fifth -- 697 cents in the first example, a less accurate 696 cents in the second (actually ~696.58 cents) -- to make the arithmetic look consistent in each example.

In another kind of situation, an extra Ab key could correct both a diminshed fourth (Wolf M3) and a diminished sixth (Wolf fifth):


     eb'             eb'             
 (737,310)       (696,310)
     c'              c'
   (427)           (386)
     g#              ab

In yet another case, two extra keys, Ab and Db, would permit a convenient Wolf correction, as would a single more remote E# key:


    g#             ab            g#
(697,270)      (696,310)     (696,310)
    f              f             e#
  (427)          (386)         (386)
    c#             db            c#

While a tuning system such as Nicola Vicentino's close approximation of 31-tone equal temperament in 1555 (virtually the same as 1/4-comma meantone) can open these and many other choices, my original example set about an impossible task.

No matter how many keys one has available in an octave, it seems mathematically impossible to construct a sonority with a just major third and minor sixth above the lowest voice where the two upper voices also form some regular meantone interval.

Most respectfully,

Margo Schulter
mschulter@value.net

------------------------------

Topic No. 4

Date: Mon, 30 Nov 1998 15:02:06 -0500
From: "Paul H. Erlich"
To: Tuning Digest
Subject: Reply to Reinhard on Subharmonics
Message-ID: <85B74BA01678D211ACDE00805FBE3C050B654D@MARS>

Now about "subharmonics": are these properly the same as "difference tones," thus produceable as the mathematical difference heard as a result of 2 higher pitches rubbing up against each other?

Absolutely not! The subharmonic series consists of frequencies in the proportions 1, 1/2, 1/3, 1/4, 1/5, 1/6 . . . . Acoustically, the most relevant features are

(a) the simple-integer ratios between all pairs of tones, and (b) all tones have a common overtone (at 1) if they are harmonic (e.g., voice, bowed strings, brass instruments).

The difference tones of the first six members of the subharmonic series are

1/2, 2/3, 3/4, 4/5, 5/6, 1/6, 1/4, 3/10, 1/3, 1/12, 2/15, 1/6, 1/20, 1/12, 1/30,

many of which are outside the subharmonic series. Meanwhile, the difference tones of the first six members of the harmonic series (1, 2, 3, 4, 5, 6) are

1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 5

which are all inside the harmonic series. Therefore difference tones are a distinctly otonal phenomenon. Summation tones are too.

Isn't the octave, what Partch once called the "aura," carved up in actual music to include the 6/5 from the very the same organic core as the 5/4? Could there even be a major withour a minor?

You are confusing the appelations "major" and "minor", which mean one thing when applied to thirds, with their synonyms "otonal " and "utonal" when applied to triads. A 6/5 is no more otonal than utonal, and the same is true of 5/4. Any single interval appears just as prominently in the harmonic series as it does in the subharmonic series. It is only chords of 3 or more notes that can be classified as "otonal" or "utonal".

------------------------------

Topic No. 5

Date: Mon, 30 Nov 1998 15:05:33 -0800
From: Carl Lumma
To:
To:
Tuning Digest
Subject: Re: Orpheus and the Undertones, Subharmonics, Utonalities etc.
Message-ID: <85B74BA01678D211ACDE00805FBE3C050B654E@MARS>

Partch credits Riemann and many others in preceding his = "utonality" concept. The concept has an intersting status = around here, with a few giving it little to no importance = (e.g., Heinz Bohlen)
I'm not sure what to make of that suggestion. Being an equal-temperament, clearly Bohlen's tuning approximates the same subharmonics as it does harmonics, and equally accurately.

Bohlen's tuning didn't start out as an equal-temperament, and even if it did, Schoenberg "derived" 12-tone equal temperament from harmonic series and not subharmonic series. Bohlen is a man, not a tuning. If you're not familiar with his views, read his web site and papers.

I hope that I am not to infer from this fragment of Heinz Bohlen's article, that he views 88CET as a competitor, or in any other way a threat, to his tuning.

He certainly does not view it as a threat, and does not even mention his own tuning in this article. He does, however, focus on difference tones, and thus rates a major triad as much more simple than a minor triad.

------------------------------

Topic No. 7

Date: Mon, 30 Nov 1998 17:45:53 -0500
From: "Paul H. Erlich"
To: Tuning Digest
Subject: Lumma's challenge
Message-ID: <85B74BA01678D211ACDE00805FBE3C050B6551@MARS>

If you allow a mistuning of 6 cents, the usual 12-out-of-31-tET scale has 39 consonant 7-limit intervals, all of which are unmistakeable representations of JI intervals. It is also equivalent to the standard keyboard tuning from 1500 to 1700 (and most organs through 1850).

If you allow a mistuning of 17 cents, a maximally-even 12-out-of-22-tET has 50 consonant 7-limit intervals. There is one ambiguity relative to JI: 600 cents can be either 7/5 or 10/7. That's no good for two-part harmony, but all the 600-cents intervals in the scale occur in several 7-limit tetrads and triads, so fuller harmony will eliminate the ambiguity.

If you allow a mistuning of 27 cents, a non-maximally-even 12-out-of-15tET has 60 consonant 7-limit intervals. There are several ambiguities relative to JI and I'm not sure that all of them can be resolved by fuller harmony (I doubt it).

Back to JI. This is the JI scale which was our first example of one with 31 exact 7-limit consonances.


	           35:24-------35:16------105:64
	         .-'/ \'-.   .-'/ \'-.   .-'/
	      5:3--/---\--5:4--/---\-15:8  /
	      /|\ /     \ /|\ /     \ /|  /
	     / | /       \ | /       \ | /
	    /  |/ \     / \|/ \     / \|/
	   /  7:6---------7:4--------21:16
	  /.-'   '-.\ /.-'   '-.\ /.-'
	4:3---------1:1---------3:2

I wrote,

Guys, wouldn't any rotation and/or reflection of this figure in the tetrahedral/octahedral lattice work too?

Carl Lumma wrote,

Should. (I presume you mean only those about which it is symmetrical)

I mean exactly the opposite. I want to end up with a different set of pitches, not the same set of pitches. Since the figure has no axes or planes of symmetry, all congruent orientations of the lattice lead to different scales. The figure is symmetrical about the central point

Just moving a structure in the lattice (called translation?) can change the number of intervals

Not true. Otherwise it wouldn't be a lattice.

Paul Hahn wrote,

the restriction of it being 7-limit makes non-orthogonal rotations fail.

What does that mean? Being 7-limit implies no such restrictions.

The other two orientations are -

There are certainly more than three orientations. Paul H., let's stick to fixed directions for the axes (more work, I know, but this stuff is confusing enough for most people).

The original scale:


	           35:24-------35:16------105:64
	         .-'/ \'-.   .-'/ \'-.   .-'/
	      5:3--/---\--5:4--/---\-15:8  /
	      /|\ /     \ /|\ /     \ /|  /
	     / | /       \ | /       \ | /
	    /  |/ \     / \|/ \     / \|/
	   /  7:6---------7:4--------21:16
	  /.-'   '-.\ /.-'   '-.\ /.-'
	4:3---------1:1---------3:2

rotated 120 degrees in the 3-5 plane (let's arbitrarily use 1:1 as the pivot):


35:27-------35:18        
   \'-.   .-'/ \      
    \ 10:9--/---\--5:3
     \  |\ /     \ /|\ 
      \ | /       \ | \   
       \|/ \     / \|  \   
      14:9---------7:6  \
         \'-.\ /.-'/ \'-.\
          \  4:3--/---\--1:1
           \  |\ /     \ /|\          
            \ | /       \ | \        
             \|/ \     / \|  \     
            28:15-\---/--7:5  \
                '-.\ /.-'   '-.\
                   8:5---------6:5

rotated -120 degrees in the 3-5 plane:



                 5:4
                 /|\
                / | \
               /  |  \
              /  7:4  \ 
             /.-'/ \'-.\
           1:1--/---\--3:2
           /|\ /     \ /|
          / | /       \ |
         /  |/ \     / \|
        /  7:5--------21:20
       /.-'/ \'-.\ /.-'/
     8:5--/---\--6:5  /
      |\ /     \ /|  /
      | /       \ | /
      |/ \     / \|/
    28:25-------42:25
       \'-.\ /.-'/
        \ 48:25 /
         \  |  /
          \ | /
           \|/
         168:125

rotated 120 degrees in the 3-7 plane:


35:27-------35:18
   \'-.  .-' / \'-.
    \ 10:9--/---\--5:3
     \  |\'/.   .\'/|\'-.
      \ | / 40:21-\-|-\-10:7
       \|/ \  |\ / \|  \ /|\
      14:9---------7:6  \ | \
          '-.\|/.\'   '-.\|  \
             4:3---------1:1  \
                '-.\ /.-'   '-.\
                   8:7--------12:7

and many more . . .

------------------------------

Topic No. 8

Date: Mon, 30 Nov 1998 17:07:57 -0600 (CST)
From: Paul Hahn
To: Tuning Digest
Subject: Re: Lumma's challenge
Message-ID:

On Mon, 30 Nov 1998, Paul H. Erlich wrote:

Paul Hahn wrote,
the restriction of it being 7-limit makes non-orthogonal rotations fail.
What does that mean? Being 7-limit implies no such restrictions.

That wasn't me, nor was any of the other stuff you quoted in that message.

--pH  http://library.wustl.edu/~manynote
    O
   /\        "'Jever take'n try to give an ironclad leave to
  -\-\-- o    yourself from a three-rail billiard shot?"

             NOTE: dehyphenate node to remove spamblock.          <*>

------------------------------

Topic No. 9

Date: Mon, 30 Nov 1998 17:14:04 -0600 (CST)
From: Paul Hahn
To: Tuning Digest
Subject: Re: Lumma's challenge
Message-ID:

On Mon, 30 Nov 1998, Paul H. Erlich wrote:

There are certainly more than three orientations. [bigsnip] and many more . . .

As I indicated in my message from this morning, there are twelve possible orientations.

--pH  http://library.wustl.edu/~manynote
    O
   /\        "'Jever take'n try to give an ironclad leave to
  -\-\-- o    yourself from a three-rail billiard shot?"

             NOTE: dehyphenate node to remove spamblock.          <*>

------------------------------

Topic No. 10

Date: Tue, 01 Dec 1998 01:19:40 +0000
From: Harold Fortuin
To: Tuning Digest
Subject: Finale xen-cidentals
Message-ID: <3663442C.52E1@wavefront.com>

For all you Finale-ists on this list:

In case you didn't already know, the Tamburo font has a few useful "xen-cidentals" which I've successfully used (all except the backwards flat, which doesn't suit me).

These are the Macintosh keystrokes; hopefully someone can translate these into Windows ones:

i = 1/2 flat (backwards and filled-in-black flat symbol)
shift-i = 1.5 flat (regular flat fused to the above)
option-m = 1/2 sharp (1 stem, instead of 2)
shift-option-n = 1.5 sharp (3 stems, instead of 2)
shift-b = backward flat (backwards and not filled in)

------------------------------

Topic No. 11

Date: Mon, 30 Nov 1998 23:39:29 -0800 (PST)
From: bram
To: Tuning Digest
Subject: Re: Lumma's challenge
Message-ID:

On Mon, 30 Nov 1998, Paul H. Erlich wrote:

Paul Hahn wrote,

Actually, I wrote the following:

the restriction of it being 7-limit makes non-orthogonal rotations fail.
What does that mean? Being 7-limit implies no such restrictions.

Umm, would you believe I was thinking in terms of a grid instead of a triangular lattice?

I picture the tuning in question as being the intersectiors of a 2x2x3 lattice, with each direction representing a ratio. Each of the three ratios can be the one which is three long, and there are four different sets of ratios which can be used:

{3,5,7} (the original given)

{1:3,5:3,7:3}

{3:5,1:5,7:5}

{3:7,5:7,1:7}

So there are a total of 12 orientations, if I understand correctly now.

9-limit tunings can't be reoriented quite so cavalierly, at least not without potentially destroying some consonances, since 3*3 is a 9-limit consonance but 5*5 isn't.

-Bram

------------------------------

End of TUNING Digest 1598
*************************


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