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PERLICH@ACADIAN-ASSET.COM wrote:
>>1. For illustrative purposes, I'll use a small prime limit JI, starting
>>in C. If I play a C major chord, the E is played about 14 cents lower than
>>12TET. If I move to a E major (using non-diatonic note for the 3rd (I don't
>>know if non-diatonic is the right word in this case)), holding the E, does
>>one usually (i) keep the E at that position and adjust each of the other
>>notes accordingly so their intervals are identical to the original C major
>>chord, or (ii) shift the E down slightly and keep the intervals the same so
>>that there is less "drift" over time, or (iii) use the intervals for the E
>>major that are implied by the original.
>
>I am unclear as to what exactly these alternatives mean. Can you please
>give some ratios, etc. to clarify?

Sorry, I could have explained this more clearly. Since I'm using borrowed
chords I want a 12 tone scale built by some combination of JI major and
minor scales. The only notes relevant in the above example are:

C E G Ab B with intervals from C of
1 5/4 3/2 8/5 15/8

Case:
(i) play E major so it has 1 5/4 3/2 ratios, then Ab is played as 25/16 =
1.56 of C instead of the "original" ratio of 8/5 = 1.6 of C

(ii) play E major with 1 5/4 3/2 ratios, but shift E down slightly so that
none of E Ab or B are played as 5/4, 8/5 and 15/8 of C respectively, but a
centered shift is done (like John A. deLaubenfels example in following
replies to my question - that's how I know what it's called :)).

(iii) Play E major using the 5/4, 8/5 and 15/8 of C (the original pitches),
so the major third is no longer 5/4 but is 32/25 = 1.28

PERLICH@ACADIAN-ASSET.COM wrote:
>>And what if two notes are held from a previous chord. If they form a
>>different interval in the two chords, which is almost always the case, one
>>or both have to shift. Any recommendations?
>
>Again, please give some specific examples.

Continue the progression given above (Cmaj - Emaj) to Abmin, so Ab and B are
held. If Abmin is to have ratios of 1 6/5 3/2, one has to play B at 48/25
=1.92 of C instead of the original 15/8, or shift both Ab and B (maybe using
again John's centered shift).

PERLICH@ACADIAN-ASSET.COM wrote:
>>My prejudice: for maximum harmony, I was intending on playing each new
>>chord as if the root of that chord is the 1 of the JI scale.
>
>That doesn't work so well for certain chords. For example, a C6/9 chord
>(C E G A D) would have the fifth between A and D as 40:27 if you tuned it
>according to "the JI major scale" on C

Do you mean the 4th of 27/20 = 1.35 between A and D? For 9, 11, 13
chords, etc., does the dominant harmonies come from the upper note
intervals, or from the correspondence with the root harmonics?

One can take this further and ask about playing one unrelated chord over
another, as seems to be commonly done in 12Tet nowadays in some genres. At
some point JI becomes irrelevant as the chord "non-harmonicity" (there's got
to be a better word, but I'm meaning in the sense the chord is written so I
don't want to use dissonance, which seems to me specific to when it's played
in a given tuning). At least this seems to be my interpretation of Arthur
Benade's sentiment.

There's a continuom from the simple triad to a Cmaj13 over a Abm7add11 where
the reasons for, and therefore the tuning used, change IMHO. I don't know
much about this area - I tend to go for the simple harmonies.

PERLICH@ACADIAN-ASSET.COM wrote:
>>approximation of a small prime limit JI subset of a large note scale (like
>>53 circle of primes or something).
>
>Circle of primes? You mean circle of fifths?

oops, yes. I need a brain change. :)

PERLICH@ACADIAN-ASSET.COM wrote:
>>Perhaps such melodic intervals are the appropriate interval to be used for
>>chord changes and modulation if the root or 1 position is not held from a
>>previous chord?
>
>The only melodic intervals that really have any "pull" as to tuning are
>the octave, fourth, and fifth, as well as whetever intervals are familiar
due to
>context and/or culture. Depending on the particular example of what you are
>describing (care to provide an example?), melodic considerations may or may not
>be able to determine the "correct" interval for such changes.

I find that Ab F C Eb (descend from Ab, rise to Eb) depends quite a bit on
the minor third intervals. Played high on the keyboard, it sounds awful to
me in 12Tet, and takes on a different feel depending on the minor third
intervals played.

Thanks to you, John deLaubenfels and all that have or will provide me with
more info. It is greatly appreciated.

Jim Savage