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~~[THIS PAGE IS A WORK IN PROGRESS...]~~

This article features just intervals created by the mechanical tonegenerator of the classical Hammond B-3 Organ model.

~~The~~ article features just intervals created by the mechanical tonegenerator of the classical Hammond B-3 Organ model.

==Design of the Hammond B-3’s Tonegenerator==

Since 1935 the Hammond Organ Company’s goal was to market electromechanical organs<ref>Webressource https://en.wikipedia.org/wiki/Hammond_organ (retrieved December 2019)</ref> with 12-tone equally tempered (12edo) tuning. The mechanical tonegenerator of the Hammond B-3 Organ is based on a set of ~~12 pairs~~ of gearwheels that make ~~twelve~~ ''driven'' shafts turn. The corresponding ~~twelve~~ ''driving'' gearwheels are mounted on a common shaft and turn all at the same rotational speed ''n1''. Certain gears reduce, others increase rotational speed.<ref>Detailed photos of a similar M-1 tonegenerator are provided by https://modularsynthesis.com/hammond/m3/m3.htm (retrieved December 2019)</ref>

Since 1935 the Hammond Organ Company’s goal was to market electromechanical organs<ref>Webressource https://en.wikipedia.org/wiki/Hammond_organ (retrieved December 2019)</ref> with 12-tone equally tempered (12edo) tuning. The mechanical tonegenerator of the Hammond B-3 Organ is based on a set of twelve ''different pairings'' of gearwheels that make (12*4) ''driven'' shafts turn. The corresponding ''driving'' gearwheels are mounted on a common shaft and turn all at the same rotational speed ''n1''. Certain gears reduce, others increase rotational speed.<ref>Detailed photos of a similar M-1 tonegenerator are provided by https://modularsynthesis.com/hammond/m3/m3.htm (retrieved December 2019)</ref>

~~Every~~ chromatic pitch class ~~has a separate~~ driven ~~shaft~~. Pure octaves are generated by dedicated ''tonewheels'' (with 2, 4, 8, 16, 32, 64 or 128 high and low points on their edges) that rotate with the driven shafts. Each high point on a tone wheel is called a ''tooth''. When the gears are in motion, magnetic pickups react to the tonewheels’ passing teeth and generate an electric signal that can be amplified and transmitted to a loudspeaker.

For every chromatic pitch class four driven shafts are installed. Pure octaves are generated by dedicated ''tonewheels'' (with 2, 4, 8, 16, 32, 64 or 128 high and low points on their edges) that rotate with the driven shafts. Each high point on a tone wheel is called a ''tooth''. When the gears are in motion, magnetic pickups react to the tonewheels’ passing teeth and generate an electric signal that can be amplified and transmitted to a loudspeaker.

For each pair of gearwheels the ratio of rotational speed ''n2''/''n1'' is determined by the inverse ratio of the gearwheels’ integer teeth numbers Z1 and Z2:

Line 11:

Line 9:

To calculate the rotational speed ''n2'' of the driven ~~shaft~~ we write

To calculate the rotational speed ''n2'' of the driven shafts we write

Line 57:

Line 55:

|-

| style="text-align: center;" | driving

Z1[teeth]

Z1[teeth]

| style="text-align: center;" | driven

Z2[teeth]

Z2[teeth]

| colspan="2" style="text-align: center;" | Fraction

| style="text-align: center;" | Ratio

Line 190:

Line 188:

== Just Intervals ==

When we associate ''“ratios of the gearwheels’ integer teeth numbers”'' with ''“frequency ratios between partials”'' we realize an intrinsic ''just interval'' determined by integer teeth numbers within such mechanical gear - even without turning the shafts! Although the Hammond Organ pretends to generate a 12edo scale, the instrument in fact creates a ~~high~~ prime limit just scale.

When we associate ''“ratios of the gearwheels’ integer teeth numbers”'' with ''“frequency ratios between partials”'' we realize an intrinsic ''just interval'' determined by integer teeth numbers within such mechanical gear - even without turning the shafts! Although the Hammond Organ pretends to generate a 12edo scale, the instrument in fact creates a ''103-prime-limit'' just scale.

== Tuning ==

The whole set of frequency ''ratios'' is fixed by the design of the gear mechanism. The driving shaft’s (A) rotational speed ''n1'' determines the instrument’s (master-)tuning. Rotating at exactly 1200 rpm (~~which equals~~ 20 rev./sec), the pitch of note A equals precisely 27.500 Hz or one of its doublings. Therefore the instrument aligns note A with a concert pitch of 440.0 Hz.

The whole set of frequency ''ratios'' is fixed by the design of the gear mechanism. The driving shaft’s (A) rotational speed ''n1'' determines the instrument’s (master-) tuning. Rotating at exactly 1200 rpm (20 rev./sec), the pitch of note A equals precisely 27.500 Hz or one of its doublings. Therefore the instrument aligns note A with a concert pitch of 440.0 Hz.

Line 220:

Line 218:

==== Example 1: Mapping a single interval====

In this ~~first~~ example we map the combination of a Hammond Organ’s note E and a higher note A ~~(a fourth up)~~ to the harmonic series.

In this example we map the combination of a Hammond Organ’s note E and a higher note A to the harmonic series.

Table 2: ~~Fourth~~ E-A

Table 2: Mapping the fourth E-A

{| class="wikitable"

Line 234:

Line 232:

! colspan="5" style="text-align: center;" |

Prime

Factorization~~...~~

Factorization

! style="text-align: center;" |

Ascending

Line 258:

Line 256:

1+(ln(P)/ln(2))

|-

| colspan="2" style="text-align: center;" | Fraction

| colspan="2" style="text-align: center;" |Fraction

(C)/(D)

|-

Line 298:

Line 296:

| style="text-align: center;" |

8.6

(Decimal printed

Decimal printed

for orientation only)

for orientation only

|}

The resulting interval ~~E-A~~ appears between partial # 206 and partial # 275. Thus the frequency ratio is (275:206), which equals 500.14 cents.

The resulting interval appears between partial # 206 and partial # 275. Thus the frequency ratio is (275:206), which equals 500.14 cents.

==== Example 2: ~~Supplementing~~ a ~~Fifth~~ ====

==== Example 2: Mapping a chord ====

~~The~~ second example illustrates how to map the resulting sus4-chord E-A-B to the harmonic series.

Adding an upper fifth (note B), the second example illustrates how to map the resulting sus4-chord E-A-B to the harmonic series.

Table 3: sus4-chord E-A-B

Line 318:

Line 316:

! colspan="6" style="text-align: center;" |

Prime

Factorization~~...~~

Factorization

! style="text-align: center;" |

Ascending

Line 342:

Line 340:

1+(ln(P)/ln(2))

|-

| colspan="2" style="text-align: center;" | Fraction

| colspan="2" style="text-align: center;" |Fraction

(C)/(D)

|-

Line 402:

Line 400:

The supplemental note B establishes an additional prime factor. We find the matching pattern of partials for this sus4-chord (1442:1925:2160) farther up in the harmonic series, where this chord spans the boundary between the 11th and the 12th octave.

==== Example 3: [...~~WILL BE CONTINUED]~~ ====

==== Example 3: Mapping all of the tonegenerator's pitchclasses ====

The full set of the Hammond Organ’s intervals resides surprisingly far up in the Harmonic Series:

* The '''44th''' '''octave starts''' at partial #(243), just below the set of partials determined by the Hammond Organ’s tonegenerator

* The '''45th''' '''octave''' starts '''right within the derived set of partials''' and starts at partial #(244)

Table 4: The full set of intervals' position in the Harmonic Series

{| class="wikitable"

! rowspan="3" style="text-align: center;" |

Pitch

Class

! colspan="2" style="text-align: center;" |

HAMMOND

Gear Ratio

(canceled)

! colspan="16" style="text-align: center;" |

Prime

Factorization

! style="text-align: center;" |

Ascending

Partial Numbers of

an Overtone Scale

! style="text-align: center;" |

Partial Found

in Octave #

|-

| style="text-align: center;" | (C)

| style="text-align: center;" | (D)

| colspan="16" rowspan="2" style="text-align: center; background-color:#cbcefb;" |

... of Column (D)

| rowspan="2" style="text-align: center;" |

Recalculated

Numerator =

Partial #

P=LCM *(C)/(D)

| rowspan="2" style="text-align: center;" |

Counted from

1/1:

Octave# =

1+(ln(P)/ln(2))

|-

| colspan="2" style="text-align: center;" |Fraction

(C)/(D)

|-

| style="text-align: center;" | C

| style="text-align: right; background-color:#ffffff;" | 85

| style="font-weight:bold; background-color:#ffffff;" | 104

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 13

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 15,003,356,791,500

| style="text-align: center;" | 44.8

|-

| style="text-align: center;" | C#

| style="text-align: right; background-color:#ffffff;" | 71

| style="font-weight:bold; background-color:#ffffff;" | 82

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 41

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 15,894,517,438,800

| style="text-align: center;" | 44.9

|-

| style="text-align: center;" | D

| style="text-align: right; background-color:#ffffff;" | 67

| style="font-weight:bold; background-color:#ffffff;" | 73

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 73

| style="text-align: center;" | 16,848,249,818,400

| style="text-align: center;" | 44.9

|-

| style="text-align: center;" | D#

| style="text-align: right; background-color:#ffffff;" | 35

| style="font-weight:bold; background-color:#ffffff;" | 36

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 3

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 17,847,130,301,000

| style="text-align: center;" | 45.0

|-

| style="text-align: center;" | E

| style="text-align: right; background-color:#ffffff;" | 103

| style="font-weight:bold; background-color:#ffffff;" | 100

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 5

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 18,907,759,758,888

| style="text-align: center;" | 45.1

|-

| style="text-align: center;" | F

| style="text-align: right; background-color:#ffffff;" | 12

| style="font-weight:bold; background-color:#ffffff;" | 11

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 11

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 20,025,870,883,200

| style="text-align: center;" | 45.2

|-

| style="text-align: center;" | F#

| style="text-align: right; background-color:#ffffff;" | 37

| style="font-weight:bold; background-color:#ffffff;" | 32

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 21,225,337,107,975

| style="text-align: center;" | 45.3

|-

| style="text-align: center;" | G

| style="text-align: right; background-color:#ffffff;" | 49

| style="font-weight:bold; background-color:#ffffff;" | 40

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 5

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 22,487,384,179,260

| style="text-align: center;" | 45.4

|-

| style="text-align: center;" | G#

| style="text-align: right; background-color:#ffffff;" | 48

| style="font-weight:bold; background-color:#ffffff;" | 37

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 37

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 23,814,549,158,400

| style="text-align: center;" | 45.4

|-

| style="text-align: center; font-weight:bold;" | A

| style="text-align: right; background-color:#ffffff;" | 11

| style="font-weight:bold; background-color:#ffffff;" | 8

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 25,240,941,425,700

| style="text-align: center;" | 45.5

|-

| style="text-align: center;" | A#

| style="text-align: right; background-color:#ffffff;" | 67

| style="font-weight:bold; background-color:#ffffff;" | 46

| style="text-align: center; background-color:#cbcefb;" | 2

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 23

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 26,737,439,929,200

| style="text-align: center;" | 45.6

|-

| style="text-align: center;" | B

| style="text-align: right;" | 54

| style="font-weight:bold;" | 35

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 5

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center; background-color:#cbcefb;" | 7

| style="text-align: center; background-color:#cbcefb;" |

| style="text-align: center;" | 28,322,303,106,240

| style="text-align: center;" | 45.7

|-

| colspan="3" |

Multiply -------->

to find (D)'s least

common multiple

(LCM)

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 2

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 3

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 5

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 7

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 11

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 13

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 23

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 37

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 41

| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 73

| style="text-align: center; font-weight:bold;" |

18,357,048,309,600

(LCM)

| style="text-align: center;" |

45.1

Decimal printed

for orientation

only

|}

== Discussion ==

No doubt - the evidence that a cluster of 12 simultaneously ringing semitones from a Hammond Organ is allocated around the 45th octave of the harmonic series is of limited practical value. The intervals' ''far-up placement'' is mainly caused by Laurens Hammond’s implementation of various prime numbers (11, 13, 23, 37, 41, 73) in different gearwheel pairings.

* Respective high-order partials are very densely spaced (in the range of ''pico-cents)'' and intervals between successive partials up there are too narrow for musical applications by far

* Due to its construction the tonegenerator selects only twelve from 17.6 trillion varieties in the 45th octave where…

** the partial number associated with the LCM, which is located exactly 8/11 below pitch class A, is not addressed because there is no gear with transmission ratio 1.000

** no pure octave above a virtual root (1/1; partial# (244)) is playable, which would ring -624.997 cents way down from pitchclass A

== General Applicability ==

The method of prime factorization to find the [[Least common multiple|LCM]] can be applied to arbitrary '''intervals, chords or scales built from rational intervals''' to identify their position in the harmonic series. Simply replace the gear-ratios by just intervals of interest.

==References==

== See also… ==

- Dismantling the tonegenarator of a scrapped H-Series Hammond Organ [8:47 min]

https://www.youtube.com/watch?v=7Qqmr6IiFLE

<nowiki>- An artist’s perception: Tony Monaco demonstrates how to apply the tonegenerator’s features of a Hammond Organ [31:10 min] </nowiki> https://www.youtube.com/watch?v=5CG81_Y8SvY

* @ 4:48 min: ''“…these sounds are in there”''

* @ 5:40 min: ''“16 foot, biggest pipes, the deepest sounds – they come from the foot”''

[[Category:Lists of intervals]]

[[Category:Instruments]]

[[Category:Organ]]

@@ Line 1: / Line 1: @@
-[THIS PAGE IS A WORK IN PROGRESS...]
+This article features just intervals created by the mechanical tonegenerator of the classical Hammond B-3 Organ model.
-The article features just intervals created by the mechanical tonegenerator of the classical Hammond B-3 Organ model.
 ==Design of the Hammond B-3’s Tonegenerator==
-Since 1935 the Hammond Organ Company’s goal was to market electromechanical organs<ref>Webressource https://en.wikipedia.org/wiki/Hammond_organ (retrieved December 2019)</ref> with 12-tone equally tempered (12edo) tuning. The mechanical tonegenerator of the Hammond B-3 Organ is based on a set of 12 pairs of gearwheels that make twelve ''driven'' shafts turn. The corresponding twelve ''driving'' gearwheels are mounted on a common shaft and turn all at the same rotational speed ''n<sub>1</sub>''. Certain gears reduce, others increase rotational speed.<ref>Detailed photos of a similar M-1 tonegenerator are provided by https://modularsynthesis.com/hammond/m3/m3.htm (retrieved December 2019)</ref>
+Since 1935 the Hammond Organ Company’s goal was to market electromechanical organs<ref>Webressource https://en.wikipedia.org/wiki/Hammond_organ (retrieved December 2019)</ref> with 12-tone equally tempered (12edo) tuning. The mechanical tonegenerator of the Hammond B-3 Organ is based on a set of twelve ''different pairings'' of gearwheels that make (12*4) ''driven'' shafts turn. The corresponding ''driving'' gearwheels are mounted on a common shaft and turn all at the same rotational speed ''n<sub>1</sub>''. Certain gears reduce, others increase rotational speed.<ref>Detailed photos of a similar M-1 tonegenerator are provided by https://modularsynthesis.com/hammond/m3/m3.htm (retrieved December 2019)</ref>
-Every chromatic pitch class has a separate driven shaft. Pure octaves are generated by dedicated ''tonewheels'' (with 2, 4, 8, 16, 32, 64 or 128 high and low points on their edges) that rotate with the driven shafts. Each high point on a tone wheel is called a ''tooth''. When the gears are in motion, magnetic pickups react to the tonewheels’ passing teeth and generate an electric signal that can be amplified and transmitted to a loudspeaker.
+For every chromatic pitch class four driven shafts are installed. Pure octaves are generated by dedicated ''tonewheels'' (with 2, 4, 8, 16, 32, 64 or 128 high and low points on their edges) that rotate with the driven shafts. Each high point on a tone wheel is called a ''tooth''. When the gears are in motion, magnetic pickups react to the tonewheels’ passing teeth and generate an electric signal that can be amplified and transmitted to a loudspeaker.
 For each pair of gearwheels the ratio of rotational speed ''n<sub>2</sub>''/''n<sub>1</sub>'' is determined by the inverse ratio of the gearwheels’ integer teeth numbers Z<sub>1</sub> and Z<sub>2</sub>:
@@ Line 11: / Line 9: @@
 <math>\frac{Z_1}{Z_2}=\frac{n_2}{n_1}</math>
-To calculate the rotational speed ''n<sub>2</sub>'' of the driven shaft we write
+To calculate the rotational speed ''n<sub>2</sub>'' of the driven shafts we write
 <math>n_2=\frac{Z_1}{Z_2}\cdot n_1</math>
@@ Line 57: / Line 55: @@
 |-
 | style="text-align: center;" | driving
-Z1[teeth]
+Z<sub>1</sub>[teeth]
 | style="text-align: center;" | driven
-Z2[teeth]
+Z<sub>2</sub>[teeth]
 | colspan="2" style="text-align: center;" | <br>Fraction
 | style="text-align: center;" | Ratio
@@ Line 190: / Line 188: @@
 == Just Intervals ==
-When we associate ''“ratios of the gearwheels’ integer teeth numbers”'' with ''“frequency ratios between partials”'' we realize an intrinsic ''just interval'' determined by integer teeth numbers within such mechanical gear - even without turning the shafts! Although the Hammond Organ pretends to generate a 12edo scale, the instrument in fact creates a high prime limit just scale.
+When we associate ''“ratios of the gearwheels’ integer teeth numbers”'' with ''“frequency ratios between partials”'' we realize an intrinsic ''just interval'' determined by integer teeth numbers within such mechanical gear - even without turning the shafts! Although the Hammond Organ pretends to generate a 12edo scale, the instrument in fact creates a ''103-prime-limit'' just scale.
 == Tuning ==
-The whole set of frequency ''ratios'' is fixed by the design of the gear mechanism. The driving shaft’s (A) rotational speed ''n<sub>1</sub>'' determines the instrument’s (master-)tuning. Rotating at exactly 1200 rpm (which equals 20 rev./sec), the pitch of note A equals precisely 27.500 Hz or one of its doublings. Therefore the instrument aligns note A with a concert pitch of 440.0 Hz.
+The whole set of frequency ''ratios'' is fixed by the design of the gear mechanism. The driving shaft’s (A) rotational speed ''n<sub>1</sub>'' determines the instrument’s (master-) tuning. Rotating at exactly 1200 rpm (20 rev./sec), the pitch of note A equals precisely 27.500 Hz or one of its doublings. Therefore the instrument aligns note A with a concert pitch of 440.0 Hz.
 <math>f_\text{A}=20.0/\text{s}\cdot\frac{88}{64}\cdot(2^4)=440.0/\text{s} = 440.0 \text{ Hz}</math>
@@ Line 220: / Line 218: @@
 ==== Example 1: Mapping a single interval====
-In this first example we map the combination of a Hammond Organ’s note E and a higher note A (a fourth up) to the harmonic series.
+In this example we map the combination of a Hammond Organ’s note E and a higher note A to the harmonic series.
-<u>Table 2</u>: Fourth E-A
+<u>Table 2</u>: Mapping the fourth E-A
 {| class="wikitable"
@@ Line 234: / Line 232: @@
 ! colspan="5" style="text-align: center;" |
 Prime <br>
-Factorization...
+Factorization
 ! style="text-align: center;" |
 Ascending<br>
@@ Line 258: / Line 256: @@
 +(ln(P)/ln(2))
 |-
-| colspan="2" style="text-align: center;" | Fraction
+| colspan="2" style="text-align: center;" |Fraction<br>
 (C)/(D)
 |-
@@ Line 298: / Line 296: @@
 | style="text-align: center;" |
 .6<br><br>
-(Decimal printed<br>
+Decimal printed<br>
-for orientation only)
+for orientation only
 |}
-The resulting interval E-A appears between partial # 206 and partial # 275. Thus the frequency ratio is (275:206), which equals 500.14 cents.
+The resulting interval appears between partial # 206 and partial # 275. Thus the frequency ratio is (275:206), which equals 500.14 cents.
-==== Example 2: Supplementing a Fifth ====
+==== Example 2: Mapping a chord ====
-The second example illustrates how to map the resulting sus4-chord E-A-B to the harmonic series.
+Adding an upper fifth (note B), the second example illustrates how to map the resulting sus4-chord E-A-B to the harmonic series.
 <u>Table 3</u>: sus4-chord E-A-B
@@ Line 318: / Line 316: @@
 ! colspan="6" style="text-align: center;" |
 Prime<br>
-Factorization...
+Factorization
 ! style="text-align: center;" |
 Ascending<br>
@@ Line 342: / Line 340: @@
 +(ln(P)/ln(2))
 |-
-| colspan="2" style="text-align: center;" | Fraction
+| colspan="2" style="text-align: center;" |Fraction<br>
 (C)/(D)
 |-
@@ Line 402: / Line 400: @@
 The supplemental note B establishes an additional prime factor. We find the matching pattern of partials for this sus4-chord (1442:1925:2160) farther up in the harmonic series, where this chord spans the boundary between the 11<sup>th</sup> and the 12<sup>th</sup> octave.
-==== Example 3: [...WILL BE CONTINUED] ====
+==== Example 3:  Mapping all of the tonegenerator's pitchclasses ====
+The full set of the Hammond Organ’s intervals resides surprisingly far up in the Harmonic Series:
+* The '''44th''' '''octave starts''' at partial #(2<sup>43</sup>), just below the set of partials determined by the Hammond Organ’s tonegenerator
+* The '''45th''' '''octave''' starts '''right within the derived set of partials''' and starts at partial #(2<sup>44</sup>)
+<u>Table 4</u>: The full set of intervals' position in the Harmonic Series
+{| class="wikitable"
+! rowspan="3" style="text-align: center;" | <br><br><br>
+Pitch<br>
+Class
+! colspan="2" style="text-align: center;" |
+HAMMOND<br>
+Gear Ratio<br>
+(canceled)
+! colspan="16" style="text-align: center;" |
+Prime <br>
+Factorization
+! style="text-align: center;" |
+Ascending<br>
+Partial Numbers of<br>
+an Overtone Scale
+! style="text-align: center;" |
+Partial Found<br>
+in Octave #
+|-
+| style="text-align: center;" | (C)
+| style="text-align: center;" | (D)
+| colspan="16" rowspan="2" style="text-align: center; background-color:#cbcefb;" |
+... of Column (D)<br><br><br><br>
+| rowspan="2" style="text-align: center;" |
+Recalculated<br>
+Numerator =<br>
+Partial #<br>
+P=LCM *(C)/(D)
+| rowspan="2" style="text-align: center;" |
+Counted from<br>
+/1:<br>
+Octave# =<br>
++(ln(P)/ln(2))
+|-
+| colspan="2" style="text-align: center;" |Fraction<br>
+(C)/(D)
+|-
+| style="text-align: center;" | C
+| style="text-align: right; background-color:#ffffff;" | 85
+| style="font-weight:bold; background-color:#ffffff;" | 104
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 13
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 15,003,356,791,500
+| style="text-align: center;" | 44.8
+|-
+| style="text-align: center;" | C#
+| style="text-align: right; background-color:#ffffff;" | 71
+| style="font-weight:bold; background-color:#ffffff;" | 82
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 41
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 15,894,517,438,800
+| style="text-align: center;" | 44.9
+|-
+| style="text-align: center;" | D
+| style="text-align: right; background-color:#ffffff;" | 67
+| style="font-weight:bold; background-color:#ffffff;" | 73
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 73
+| style="text-align: center;" | 16,848,249,818,400
+| style="text-align: center;" | 44.9
+|-
+| style="text-align: center;" | D#
+| style="text-align: right; background-color:#ffffff;" | 35
+| style="font-weight:bold; background-color:#ffffff;" | 36
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 3
+| style="text-align: center; background-color:#cbcefb;" | 3
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 17,847,130,301,000
+| style="text-align: center;" | 45.0
+|-
+| style="text-align: center;" | E
+| style="text-align: right; background-color:#ffffff;" | 103
+| style="font-weight:bold; background-color:#ffffff;" | 100
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 5
+| style="text-align: center; background-color:#cbcefb;" | 5
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 18,907,759,758,888
+| style="text-align: center;" | 45.1
+|-
+| style="text-align: center;" | F
+| style="text-align: right; background-color:#ffffff;" | 12
+| style="font-weight:bold; background-color:#ffffff;" | 11
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 11
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 20,025,870,883,200
+| style="text-align: center;" | 45.2
+|-
+| style="text-align: center;" | F#
+| style="text-align: right; background-color:#ffffff;" | 37
+| style="font-weight:bold; background-color:#ffffff;" | 32
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 21,225,337,107,975
+| style="text-align: center;" | 45.3
+|-
+| style="text-align: center;" | G
+| style="text-align: right; background-color:#ffffff;" | 49
+| style="font-weight:bold; background-color:#ffffff;" | 40
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 5
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 22,487,384,179,260
+| style="text-align: center;" | 45.4
+|-
+| style="text-align: center;" | G#
+| style="text-align: right; background-color:#ffffff;" | 48
+| style="font-weight:bold; background-color:#ffffff;" | 37
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 37
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 23,814,549,158,400
+| style="text-align: center;" | 45.4
+|-
+| style="text-align: center; font-weight:bold;" | A
+| style="text-align: right; background-color:#ffffff;" | 11
+| style="font-weight:bold; background-color:#ffffff;" | 8
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 25,240,941,425,700
+| style="text-align: center;" | 45.5
+|-
+| style="text-align: center;" | A#
+| style="text-align: right; background-color:#ffffff;" | 67
+| style="font-weight:bold; background-color:#ffffff;" | 46
+| style="text-align: center; background-color:#cbcefb;" | 2
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 23
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 26,737,439,929,200
+| style="text-align: center;" | 45.6
+|-
+| style="text-align: center;" | B
+| style="text-align: right;" | 54
+| style="font-weight:bold;" | 35
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 5
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" | 7
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center; background-color:#cbcefb;" |
+| style="text-align: center;" | 28,322,303,106,240
+| style="text-align: center;" | 45.7
+|-
+| colspan="3" |
+Multiply --------><br>
+to find (D)'s least<br>
+common multiple<br>
+(LCM)
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 2<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 2<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 2<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 2<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 2<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 3<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 3<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 5<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 5<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 7<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 11<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 13<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 23<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 37<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 41<br><br><br><br>
+| style="text-align: center; font-weight:bold; background-color:#cbcefb;" | 73<br><br><br><br>
+| style="text-align: center; font-weight:bold;" |
+,357,048,309,600<br><br>
+(LCM)<br><br>
+| style="text-align: center;" |
+.1<br>
+Decimal printed<br>
+for orientation<br>
+only
+|}
+== Discussion ==
+No doubt - the evidence that a cluster of 12 simultaneously ringing semitones from a Hammond Organ is allocated around the 45<sup>th</sup> octave of the harmonic series is of limited practical value. The intervals' ''far-up placement'' is mainly caused by Laurens Hammond’s implementation of various prime numbers (11, 13, 23, 37, 41, 73) in different gearwheel pairings.
+* Respective high-order partials are very densely spaced (in the range of ''pico-cents)'' and intervals between successive partials up there are too narrow for musical applications by far
+* Due to its construction the tonegenerator selects only twelve from 17.6 trillion varieties in the 45<sup>th</sup> octave where…
+** the partial number associated with the LCM, which is located exactly 8/11 below pitch class A, is not addressed because there is no gear with transmission ratio 1.000
+** no pure octave above a virtual root (1/1; partial# (2<sup>44</sup>)) is playable, which would ring -624.997 cents way down from pitchclass A
+== General Applicability ==
+The method of prime factorization to find the [[Least common multiple|LCM]] can be applied to arbitrary '''intervals, chords or scales built from rational intervals''' to identify their position in the harmonic series. Simply replace the gear-ratios by just intervals of interest.
 ==References==
 <references />
+== See also… ==
+- Dismantling the tonegenarator of a scrapped H-Series Hammond Organ [8:47 min]<br>
+https://www.youtube.com/watch?v=7Qqmr6IiFLE <br>
+<nowiki>- An artist’s perception: Tony Monaco demonstrates how to apply the tonegenerator’s features of a Hammond Organ [31:10 min] </nowiki><br>https://www.youtube.com/watch?v=5CG81_Y8SvY
+* @ 4:48 min: ''“…these sounds are in there”''
+* @ 5:40 min: ''“16 foot, biggest pipes, the deepest sounds – they come from the foot”''
+[[Category:Lists of intervals]]
+[[Category:Instruments]]
+[[Category:Organ]]