On 05-17-13 8:11 AM,
gabem...@gmail.com wrote:
> Hi Joey,
> Thinking out loud in regards to Acoustic Root Theory.
>
> C (130.8 Hz)
>
> C C G C E G Bb C D E F# G A Bb B C C# D D# E F F# F# G G# G# A A# A# B B
> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Tip: You need to use a mono-spaced font, like Courier, if you want the
letter names and the partial numbers to line up in a usenet post.
I've rearranged your text list on my system using a mono-spaced font, so
you should be able to see the letters and numbers lining up correctly now.
If not, and you're using GoogleGroups to read this newsgroup, then make
sure you select the mono-spaced font option.
If you're using a dedicated newsreader then check your prefs for same.
The 13th partial is a pitch that is between an equal tempered (ET) Ab
and A but for most musical theories that I'm acquainted with it is
usually identified with A.
The 26th partial will be this same pitch, one octave higher.
The pitch of the 23rd partial is somewhere between F# and G but F# is
closer to the 11th and 22nd partials.
In ET those high A#'s will be equivalent to an octave doubling of the
7th partial.
7, 14, 28... So A# is the 28th partial and the 29th partial is somewhere
between Bb and B.
etc.
But for most practical music making purposes that I've seen, the OTS is
rarely invoked above the 13th partial.
> Does this go on?
Goes on to infinity if you want to.
> When do we stop being able to audibly perceive the overtones?
Only the very lowest notes, e.g. A-27.5hz - the lowest A on a full-sized
piano keyboard, will you hear any individual audible overtones.
But the timbre of a note will be created by the relative amplitudes of
the various overtones and their in-or-out-of-tuneness.
Overtones don't have to be audible in order to affect the feeling of an
interval's or a chord's acoustical root.
IMO There is some sort of as-yet-to-be-identified mechanism in the human
mind that looks for and recognizes frequency ratios within the sound
waves that hit the human ear.
This probably evolved with humans being able to distinguish the octave
or so difference between the male and female voice and progressed
somehow from there.
As you should know, octave equivalence, is a feature of almost all
pitched music across almost all cultures one of the main exceptions
being the Gamelan music of Bali in which octave equivalence has little
if any role.
You do believe in octave equivalence in your theory, don't you?
As far as why it is that most people have not heard about acoustical
root theory...
There are certain scholars who claim to have discredited it and many of
the writings of the people who believe in the theory are either hard to
parse (e.g. Rameau and Hindemith) or logically inconsistent (e.g. Delamont).
Still, I've become a believer myself, based on my exposure to the
Delamont book, because the results I get when applying it are, more
often than not, very useful to me as a way of understanding certain
vertical qualities of most possible chord voicings.
I didn't want to get into this, but here's the theory explained...
The first overtones of a fundamental tone possess all the tones of the
major triad.
Here's the lower part of the OTS of A-110hz:
A110 A220 E330 A440 C#550
So the frequency ratio between A and E is either 3:1 (P12th) or 3:2. (P5th)
Other than a unison or an octave, these are the simplest freq ratios
possible.
This theory states that intervals with the simplest freq ratio exhibit
the strongest sense that the fundamental of that ratio (i.e. the "1") is
the root of the interval.
Whenever a chord voicing has a P5th or P12th interval as the lowest
interval in the chord you will have a real hard time hearing any note
other than the bass note as the root of that entire chord, no matter how
dissonant the intervals within the upper voices of the voicing happen to be.
The next simplest freq ratios are 5:1, 5:2 and 5:3 corresponding to a
maj 18th, a maj 10th and a maj 3rd.
So, a close-voiced Amaj triad built on A440 has the freq ratio of 6:5:4.
E6600:C#550:A440
[Notice that the first instance of the min 3rd interval occurs in the
OTS between the 6th and 5th partials.
Notice also that there is something akin to a min 3rd interval between
the 6th and 7th partials.]
We can see at this point that any inversion of an Amaj triad will still
have the same fundamental or an octave transposition of that fundamental
as its root (aka its "1") because every interval in any voicing of an
Amaj triad will have a as the root of that interval.
1st inv: C# E A (8:6:5)
C#-E is a min 3rd with a freq ratio of 6:5. The only fundamental tone
that has C# as its 5th partial and E as its 6th partial is A. So the
root of C#-E is A.
E-A is a P4th interval with a freq ratio of 4:3 or 8:6.
The only fundamental tone that has E as its 3rd or 6th partial as well
as A as its 2nd or 4th partial is A.
The ac rt of C#-A is also A. (8:5)
Therefore A is the root of the entire chord.
2nd inv: E A C# (5:4:3)
The ac rt of E-A is A. (4:3)
The ac rt of A C# is A. (5:4)
The ac rt of E-C# is A. (5:3)
Therefore A is the root of the entire chord.
That's what "root" actually means.
I.e. A chord's root is the perceived fundamental frequency (the "1") of
the entire chord.
When we hear chords whose intervals are spaced differently than the
intervals of a single tone's fundamental frequency, or whose intervals
all have different fundamentals, we experience that chord as having a
less strong feeling of root as well as increased vertical tension.
If the intervals of the voicing are so out of alignment with those in
the OTS the chord might not have a feeling of root at all.
Now let's look at dim triads next.
C# E G = 7:6:5 with A being = to 1. (Ignoring the fact that E-G can also
be seen as partials 5 and 6 of C)
So the ac rt of a dim triad is a tone that isn't even in that triad.
Every interval in a dim triad can be seen as having the same ac rt, so
every inversion of a dim triad will have the same ac rt.
There is no other possible tone whose overtones more closely resemble
those of a C# dim triad, within the lower regions of its OTS, than the
tone A.
1st inv: E G C#
The ac rt of E-G, if heard as an isolated interval, would be seen as
being C (i.e. 6:5 of the OTS of C).
But the other candidate for the root of E-G is of course A, in which
case the partial numbers would be a bit higher @ 7:5.
Higher partial numbers will impart a less pronounced root feeling.
G-C# could be 11:8 of G or 10:7 of A. Notice that A involves lower
partial numbers.
E-C# unambiguously has a root on A @ either 5:3 or 10:6.
And because of the strong root feeling of E-C# as well as the fact that
each of the other intervals is also found within the OTS of A we can
confidently say that the ac rt of the entire chord is A.
Now min triads are a bit more complicated.
A C E
The ac rt of A-C is F (@ 6:5).
In another chord we might deem it to have a root on D (@ 7:6).
The ac rt of C-E is unambiguously C (@ 5:4).
The ac rt of A-E is unambiguously A (@ 3:2 or 6:4).
So within this Am triad we have all these notes, F C D and A competing
for prominence within the ear.
But because of the presence of the strongest interval, the P5th between
A and E, the ear is swayed that A is the ac rt of the entire chord.
Take away either the A or the E and the remaining intervals (A-C, or
C-E) will not have A as their ac rt.
This means that when the Am triad is heard as a whole, that the C is
experienced as a distorted version of A's 5th partial.
I denote distorted partial numbers with an asterisk next to them.
A C E = 6:5*:4 of A.
There is no other possible tone whose overtones more closely resemble
those of a close-voiced Am triad, within the lower regions of its OTS,
than the tone A.
1st inv
C E A
C-E is 5:4 of C.
E A is 4:3 (or 8:6) of A.
C-A is 5:3 of F.
But taken as a whole, because of the strong root suggestion of the
interval E-A, the chord will be experienced with an ac rt of A with the
following partial numbers: 8:6:5*.
There is no other possible tone whose overtones more closely resemble
those of a 1st inv Am triad, within the lower regions of its OTS, than
the tone A.
2nd inv
E A C
E-A is 4:3 of A.
A-C is 6:5 of F.
E-C is 8:5 of C.
But taken as a whole, because of the strong root suggestion of the
interval E-A, the chord will be experienced with an ac rt of A with the
following partial numbers: 5*:4:3.
There is no other possible tone whose overtones more closely resemble
those of a 1st inv Am triad, within the lower regions of its OTS, than
the tone A.
This distorted 5th partial accounts for the stronger vertical tension of
min triads vs that of maj triads.
Aug triads:
A C# E#
The ac rt of A-C# is A (@ 5:4).
The ac rt of C#-E# is C# (@ 5:4).
The ac rt of A-F is F (@ 8:5).
With A-C# at the bottom of the voicing with its simple 5:4 ratio it will
sway the ear that a is the ac rt of the entire chord which means that
the E# is being experienced as a distorted 6th partial.
6*:5:4.
The other 2 inversions of this triad will both feel as if the lowest
tone is the ac rt of the chord.
The theory of course can be expanded upon to include 7th, 9th, 11th,
13th and non-tertian chords of any size.
In a nutshell it boils down to the idea that the when presented with
several simultaneously sounding intervals the ear tries to hear them as
all originating from a single fundamental tone.
To the extent that the chord's intervals match those of a single
fundamental that chord will be the most in harmony and the least
vertically dissonant as well as having the most pronounced feeling of root.
To the extent that the chord's intervals don't match those of a single
fundamental that chord will be less harmonious and the more vertically
dissonant as well as having a less pronounced feeling of root.
That's it for now.
I'm all typed out.
No time to proof read either.
Sorry for any mistakes or typos.
For more, check Gordon Delamont's Modern Harmonic Technique, Vol 1,
Kendor Press.
> Primary chords created by stacking intervals (from the 31 tones above)
The 12 tone scale exists within the first 21 or 25 partials.
From the OTS of A:
A C# E G B D# F/F# G# A# C D
4 5 6 7 9 11 13 15 17 19 21
or
A C# E G B D# F# G# A# C D F
4 5 6 7 9 11 13 15 17 19 21 25
> 1/43, 1/35, 1/3#4, 1/b3#5, 1/23, 1/23, 1/2b3, 1/b2b3, 1/2b3, 1/b22, 1/b22
Whatever.
I don't see the need to invoke the OTS in what you're doing.
> 8 Primary Chords (created by stacking intervals), only 2 belong to the same chord family (6 chord groupings of the 110 primary chords)
>
> *just an observation
>
> Intervals (based from the C 1), and C 16)
>
> 1-17
> every interval is present 1x, perfect 5th (3), major 3rd (2), minor 7th (2),
>
> 16-31, every interval is present 1x, aug 4th (2), aug 5th (2), min 7th (2), maj 7th (2)
I don't understand what you've written above and don't really care.
Is there a reason I should care?
> In acoustic root theory the combinations of all that is going on above with one note then interacts with 2 other notes (for a triad), the resulting combination of all the interactions has a tone that is most closely related to all those interactions in terms of consonance. This would be known as the acoustic root.
> Is this correct?
Not "in terms of consonance". In terms of the feeling of root.
Consonance and dissonance are subjective terms and have meant different
things to different composers in different cultures and at different times.
Dissonance simply means the feeling that an interval or chord is in need
of resolution.
That need is governed by style for the most part and not necessarily by
virtue of any vertical characteristic of a chord.
Classical composers felt that 2nd inversion maj and min triads were in
need of resolution and treated the P4th interval as a dissonance even
though the P4th has one of the simplest frequency ratios possible, 4:3.
In jazz and in more modern form of maj/min tonality 2nd inv triads are
not treated as dissonances.
So other terms are need to describe what ypu're talking about, like
density, tension or fusion and these characteristics *are* affected by a
chord's intervals acoustical roots.
The more implied partials and/or distorted partials present within a
chord voicing, the more dense or tense sounding that chord will be.