Because of my interest in analog synthesizer technology, and the fact that I am an jazz organ player, specifically, a Hammond organ player, I thought it would be fitting to do a report explaining the technology used in the original Hammond organs (quite possibly the world’s first synthesizers), and explain how their immense popularity in the 50’s and 60’s helped shape the technology of the earliest synthesizers, and the needs of early keyboard players in general.
The Hammond B-3
There were many varieties of the Hammond organ, some designed for home use, some designed for church use, and some designed for live gigs and studio recording. But the most popular variety, and the one still commonly in use today (if you can find one that isn’t too beat up) is the Hammond B-3. This organ has two 61 note keyboards, (manuals), sometimes called the swell (top) and the great (bottom), a variety of built-in special effects, (including "percussion" effects, several different chorus and vibrato effects, and adjustable attack and decay effects), 9 preset keys for both manuals, (the inversely white and black keys on the bottom octave of each manual), two sets of nine stops (drawbars) for each manual, a full two octave set of foot pedals with two pedal drawbars built in to the console, a volume pedal (expression pedal) built into the base, a solid walnut body with 4 legs and base, a built-in stool, and it weighed in at over 400 pounds.
Also, it needed to be run through a separate speaker called a Leslie (which I will explain later), which also came in many varieties and sizes, but which was usually around six feet tall and weighed almost as much as the organ. To get a B-3 to a gig, you would probably need a truck or a van to transport it, a dolly or three to four guys to carry it, and then a prayer that you didn’t have to carry it up too many flights of stairs.
Why, you must be wondering, would any sane musician want to take this piece of furniture with them out to a gig? If you have ever heard a good B-3, you would understand. A Hammond B-3 can all at once sound like a carnival, a big band, a horn section, a small jazz combo, a funk group, a percussion section, a flute, and/or countless other things. How does one instrument manage to do all this? The answer begins in the drawbars.
The Drawbars
You’ve heard the expression, "Pulling out all the stops?" The drawbars on the organ are these very stops. The organist can "voice" each stop as he plays. Meaning, any one of the nine drawbars that go into the makeup of an organ sound can be individually altered, either while playing, or permanently preset into one of the 9 preset keys. (The other three are for setting or clearing the presets.) Each drawbar has eight degrees to which it can be literally "drawn" or pulled, out of the console of the organ, the eighth being the loudest, and all the way in being silence.
The nine drawbars represent the nine most important harmonics, going in order of left to right, the sub-octave, the fifth, the unison or fundamental octave, the 8th, the 12th, the 15th, the 17th, the 19th, and the 22nd. All of these except the 17th are either roots or fifths. The 17th is a third. The colors on the drawbars themselves are also related to their harmonic pitch. The white and brown drawbars are called the consonants, all the roots and the lower fifths, and the black drawbars are called the dissonants, the higher fifths and the third. Using this basic harmonic series, almost any instrumental tone may be imitated or mimicked.
Also, the inventor of the Hammond organ, Laurens Hammond, who invented the B-3 around 1937-39, and who later unveiled it at the 1939 AES show here in New York City at the RCA building, used some of his father’s techniques, who happened to be a designer of pipe organs, in the development of his new organ. The drawbars are all labeled to represent pipe pitches, represented by length, ranging in order of largest to smallest, from left to right. These "lengths" are, 16', 8', 5 1/3', 4', 2 2/3', 2', 1 3/5', 1 1/3', and 1', being the smallest. By the way, the two drawbars for the pedals are called the Super-Octave and the Sub-Octave, and their respective "lengths" are 16' and 8'.
Just like the fundamentals for creating sound waves lies in harmonics, (much like what we have learned in this class,) such is the way with the drawbars and their harmonic series. For instance, in terms of sound waves and frequency, the 1st harmonic by itself creates a sine wave, or a flute/recorder-type sound. The odd harmonics create a square wave, or a clarinet-like sound. The odd harmonics "squared" create a triangle wave, or a string-like sound. And all harmonics together create a sawtooth wave, or an oboe-like sound. Drawbar settings use the same kind of premise; various levels and volumes of harmonics are used to create sounds.
There are literally millions of tone qualities and endless shades of dynamic level available on the Hammond organ. Figure 1, (see back pages), or drawbar setting (00 6200 000) is an example of a flute tone. Figure 2 (00 4345 554) is an example of a violin tone. Figure 3 (00 6876 540) is an example of a trumpet-like tone, and Figure 4 (54 5444 222) is an example of a diapason, or a typically organ-like tone quality. There are also the typical jazz settings (not included in the appendix,) such as 88 8000 000, the most common, used by jazz players 90% of the time, 88 8400 080, for a bit more of a whistle during solos, 80 0000 088, for a high-end chordal voice setting, or the full blown 88 8888 888, the largest sound possible on the organ, which is used usually for loud chord solos, or huge crescendos or climaxes. That particular setting truly defines the phrase "pulling out all the stops", and it means exactly what it says; the works. Of course, there are a multitude of other possibilities, and every player out there has his or her own particular setting, or 'sound'. But how exactly do the drawbars do what they do? The answer to that lies in the tone generator.
The Tone Generator
The tone generator, except for the Pedal Solo Unit, which controls the sound generated by the pedals, is composed of 91 tone wheels, located inside the console. Each tone wheel generates magnetically one of the pitches of the fundamentals (the first harmonic) or the overtones, (all harmonics above the fundamental) of the many "stops". By the way, musical pitches on the organ range from 32.692 Hz in the bass to 5919.85 Hz in the treble, a span of seven and a half octaves.
The frequencies of the Solo Unit for the pedals range from 16 to 3136 cycles per second. The expression pedal has a range over 48 decibels in power. (The B-3 is a loud instrument.) Anyhow, on the outer rim of each tone wheel, which are only about the size of silver dollars, are a series of "hills and valleys" which disturb the electromagnetic field in a near-by magnet and the circuitry with which it is connected. These wheels turn on their axles at a carefully controlled speed. The disturbances are in the nature of sine waves, and are timed as the musical pitches themselves.
These disturbances, which are really just fluctuations of electrons in tubes and wires, are extremely weak and have to be amplified millions of times before they are strong enough to move the cones in the external speakers, which, in turn, must move all of the tons of air in a room before the sound actually gets to you, the listener. The waves, while they are still in the electrical form, pass through an amazing set of filters, mixers, and other devices that process the final result, but to the player, it is so much more less complicated than all of that......
See the complete history on http://www.theatreorgans.com/grounds/docs/history.html
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