Conjunct & Disjunct Tetrachord Combinations in Makam
The following quote notates how the pentachord and the tetrachord is combined to create a full scale, the page online has midi examples, so go to that if you are really interested.
II. WAYS OF TETRACHORDS COMBINING
Scales of Azerbaijani modes are structured by combination of tetrachords represented in succession of 4 diatonic degrees.
Tetrachords within perfect quartes (Perfect 4ths) are called perfect ones.
Tetrachords within increased quartes (Augmented 4ths) are called increased.
Tetrachords within diminished quartes (Diminished 4ths) are called diminished.
Tetrachords can be combined in 4 ways:
1st way - chain combination, i.e. a combination where the last tone of the lower tetrachord coincides with the first tone of the upper tetrachord. An interval formed is a perfect prima. In the manuals on music theory such combinations are called conjoint ones.
2-nd way - mixed combination, i. e. a combination where the last tone of the lower and the first tone of the upper tetrachords form the interval of the major second which is called separate combination.
3-rd way - combination by intermediate semitone, i.e. a combination where an interval of the minor third is formed between the last tone of the lower and the first tone of the upper tetrachords.
4-th way - combination by intermediate tone, i. e. a combination where an interval of the major third is formed between the last tone of the lower and the first tone of the upper tetrachords.
Combined or joined tetrachords can be equal or unequal by their structure.
Combination of equal tetrachords forms consequent succession of degrees in the order of scales. When the 1-st way of combination is applied to perfect tetrachords, identical in structure, it forms a scale consisted of gradual succession of perfect quartes.
This way of "tagging" on the various tetrachords together reminds me of the Greek method of systematizing their varieties of four note and five note scales to create their families of scale genus. Itis common knowledge that the Makam is really the closest surviving cultural method that preserves the Pythagorean ratios of dividing the octave, but it also heir to the Greek idea of "Conjunct" & "Disjunct" combination. For example, this is from the philosopher Aristoxenous's "Harmonika Stoicheia":
Successive Tetrackords are either Conjunct or Disjunct.
WE shall employ the term conjunction when two succès
sive tetrachords, similar in figure, have a common note ; the
term disjunction, when two successive tetrachords similar in
figure are separated by the interval of a tone. That successive
tetrachords must be related in either of these ways, is evident
from our axioms. For a series, in which each note forms
a Fourth with the fourth note in order from it, will constitute
conjunct tetrachords; while disjunct tetrachords result, when
each note forms a Fifth with the fifth from it. Now as all
successions of notes must fulfil one or other of these conditions,
so all successive similar tetrachords must be either
conjunct or disjunct.
Difficulties have been raised by some of my hearers on
the question of succession. It has been asked, Firstly,
what is succession in general? Secondly, does it appear in
one form only, or in several? Thirdly, are conjunct and
disjunct tetrachords equally successive ? To these questions
the following answers have been given. In general, scales
are continuous, whose boundaries either are successive or
coincide. There are two forms of succession in scales ; in
the one, the upper boundary of the lower scale coincides
with the lower boundary of the upper scale ; in the other,
the lower boundary of the higher scale is in the line of
succession with the higher boundary of the lower scale. In
the first of these forms, the scales of the successive tetrachords
have a certain space in common, and are necessarily
similar in figure. In the other form, they are separated
from one another, and the species of the tetrachords may
be similar, only on condition, however, that the separating
interval is one tone. Thus we are led to conclude that two
similar tetrachords are successive, if they are either separated
by a tone, or if their boundaries coincide. Consequently
similar successive tetrachords are either conjunct or disjunct.
We also assert that two successive tetrachords either
60 must be separated by no tetrachord whatsoever, or must not
be separated by a tetrachord dissimilar to themselves.
Tetrachords similar in species cannot be separated by a
dissimilar tetrachord, and dissimilar but successive tetrachords
cannot be separated by any tetrachord whatsoever.
Hence we see that tetrachords similar in species can be
arranged in succession in the two forms above mentioned.
The interval contained by successive notes is simple.
For if the containing notes are successive, no note is
wanting; if none is wanting, none will intrude; if none
intrudes, none will divide the interval. But that which
excludes division excludes composition. For every composite
is composed of certain parts into which it is divisible.






