An Introduction to Drawbars

 

 
The Drawbars are the heart and soul of the sound of your Hammond Organ. There are two sets of nine Drawbars, sometimes referred to as Tonebars, for the Upper and Lower Manuals and two Drawbars for the Pedals, located between the Upper Manual and the Information Center Display.

Pulling a Drawbar out (towards you) will increase the volume in incremental steps from 0 (no sound) to 8 (maximum volume). Pushing the Drawbar in (away from you) decreases the volume of that Drawbar.

Your Hammond Organ has two sets of nine Drawbars, one for each manual. Drawbars, often called Tonebars, are the heart and the basis of the renowned Hammond Sound and have been used since the first Hammond Organ Model A introduced in 1935.

There are approximately 253,000,000 possible sound combinations that can be produced by these Drawbars. Each Drawbar consists of sine waves of different pitches (which means tone depth). The illustration below shows how each Drawbar relates to the manual when middle "C" is pressed.

Each Drawbar is marked with a number followed by a footage mark. For example, the first white drawbar is marked "8'". This is pipe organ terminology indicating that the pipe used to produce the lowest note on the keyboard on a pipe organ is actually eight feet long. The numbers from "1" to "8" on each Drawbar represent degrees of loudness - number 1 being the softest, and number 8 being the loudest.

To take the fullest advantage of the harmonic Drawbars of the Hammond Organ, it is necessary to understand what "music" really is.

All sounds, musical or otherwise are created by sending impulses or vibrations through the air. These are "felt" in the sensitive mechanism of our ears - a process we call "hearing". While you may think that you hear a single individual sound, actually each sound, or musical note, consists of a "fundamental" or basic tone, and a number of "harmonics" or overtones - the latter being different when the same note is played on different instruments.

For instance, when you play "A" above middle "C" on any instrument - organ, piano, violin, trumpet, or any other - you are creating a vibration at the rate of 440 impulses per second, provided of course that the instrument is in proper tune. This is known as the "fundamental" of this "A". However, the harmonics or overtones which accompany this fundamental of "A" on the piano would be quite different from those you would hear if you played the same note on, say, a violin or a trumpet. This difference in harmonic structure is what distinguishes the sound of a piano from that of a violin or another instrument, and is created by a combination of differences in the materials and shape of the instrument, and the manner of playing.

Now it is apparent that if you have available a source of sound which will provide the fundamental sound of each note on the keyboard, plus a source of a large number of harmonics, you are in a position to combine these fundamentals and harmonics into musical tones similar to those of almost any instrument with which you may be familiar. And that is just what the harmonic Drawbars of the Hammond Organ do for you.

 

Drawbars are divided into 3 groups of sound as well as 3 groups of color. We will first look at the 3 sound groups.

You may think of these sound groups in terms of the three levels - The Sub being the deep pitches, the Foundation being the mid range of pitches and the Brilliance being the high pitches.

 

TRY THIS:

Make sure all Drawbars are "IN" (off) and the Cancel Touch Button is lit.

Hold down middle "C" on the Upper Manual.

Pull the first white Drawbar in the group of Drawbars for the Upper Manual, marked "8'", all the way out.

While continuing to hold middle "C" down, pull the first brown Drawbar in the group of Drawbars for the Upper Manual, marked 16', all the way out. You will now hear the sound of "C" one octave lower being added.

Now pull the second brown Drawbar in the same group out, and you will hear it add a richness to the sound of the "C" note that you are holding down.

Regardless of the size of a pipe organ or its number of stops, all of its voices are related to four basic families of tone. The four basic families - Flute, Reed, String and Diapason - can be quickly set up on the Drawbars by relating a pattern or shape to each family.

These are the generalities which apply to the tonal resources of the organ, and in themselves produce pleasant and usable effects. However, real beauty of tone is secured in two ways. The first way is to use registrations which have been devised by organists. The second way, and eventually the one that best expresses your own feeling for the music, is to create your own tonal effects, experimenting with and perfecting tones which you use to play your favorite selections.

The Hammond Organ Drawbars allow you not only to set up any tonal effect you want, but also to make many fine variations of the tone. Only with the Hammond Drawbars can you play exactly the shade of tone you want for every selection and, perhaps even more important, for every size and type of room in which you play.

With the Hammond Organ Drawbars, a touch of a finger is all that is needed to make the tone quality softer or more brilliant, richer in one harmonic or another.

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