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Hammond Percussion

(Excerpted from the OriginalHammondLeslieFaq.)

Hammond Percussion is the name that Hammond gave to a patented circuit that changed the attack characteristic of a note. It does this by adding an additional tone, the Percussion signal, to the note that is depressed. The envelope of the Percussion signal is controlled to have a specific decay characteristic. The frequency of the Percussion signal is selectable to be either the 2nd or 3rd harmonic of the depressed note. The audible effect of this is that there is a chirp or ping at the attack of the note.

In modern keyboard parlance the Hammond Percussion would be called "single triggered". The Percussion envelope amplifier is triggered only when a note is depressed from an all-keys-up state. After it has been triggered and as long as any upper manual keys remain depressed, no Percussion effect will be heard when additional notes are depressed. Thus to hear the percussion effect for every note of a run requires a technique that fully releases the currently pressed key prior to depressing the next one in the run.

When Percussion is enabled, one of the harmonic BusBar contacts from each key is used to trigger the Percussion amplifier. This removes one Drawbar harmonic from the palette available to shape the sound. The stock setup removes the harmonic available at the 9th Drawbar. Some players, however, prefer to have the top-most Drawbar available at all times, even when Percussion is enabled. See PercussionModifications.

On the ConsoleOrgans equipped with percussion, it is enabled only on the upper manual, and only while using the "B" Preset. See also FourUp.

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