Grinnell College Musical Instrument Collection


3 items

continuo organ

This continuo organ is a keyboard-operated edge aerophone consisting of many vertically-mounted end-blown duct flutes the blowing ends of which are situated inside a wind chest that is fed by a motorized pump. Made in 2001 by the American firm of Bennett-Giuttari (Rehoboth, MA), the organ pictured and described here is based on instruments made by the 17th century German organ builder Nikolaus Manderscheidt. While there is solo literature appropriate for this sort of organ, its primary use is as an accompanying instrument for both vocal and instrumental soloists and ensembles (see Baroque Trio Sonata). Such continuo organs are being made today to provide professional and student early music ensembles with an instrument appropriate for period performance of Baroque music. Choral societies and churches also purchase such instruments as a less costly alternative to a full sized pipe organ. While large pipe organs are found in cathedrals and churches, and in some concert halls, throughout the world, the global distribution of smaller and more specialized continuo organs such as this one is less clear; in all likelihood, continuo organs are more likely to be encountered today in Europe and the Americas than elsewhere in the world. Description This small organ has a single keyboard manual with fifty-one keys covering, chromatically, a range of four octaves and a whole step. Inside the box case of the instrument (which functions as a resonating chamber) are located one-hundred-fifty-three single-pitch cylindrical bore pipes of the duct flute type, all of them quadrangular wood pipes of varying lengths and designs, grouped into three sets, called ranks, each with 51-pipes of similar design (see the detail photo for a view of the interior of the sound chest). On the right side is located the Gedeckt rank, which is a type of stopped pipe. To its left is a second rank, this one consisting of half-stopped pipes (a metal tube penetrates through the plug that stops the pipe) called Rhorflöte. The final Holtzprincipal rank is only partially visible at the left side of the photo. Its lower-pitched pipes are fully stopped while the rest are half-stopped. A stopped pipe produces a pitch an octave lower than an open pipe of comparable length. The foot of each pipe fits into a hole on the top of a large rectangular slider chest, which controls which ranks of pipes are available to be sounded. The slider chest rests on top of an equally large, two-layer pallet box. The bottom layer of the pallet box is a large reservoir filled with pressurized air delivered from the pump. The upper layer of the pallet box consists of 53 long and narrow chambers called grooves. Above each groove is located the foot end of the pipe in each rank that is operated by a single key on the keyboard. To get pressurized air from the general reservoir into a specific groove, a spring-loaded pallet valve located between the reservoir and the groove must be opened. This is accomplished by depressing the desired keyboard key, which through a number of mechanical linkages opens the pallet valve for a particular groove. Player - Instrument Interface and Sound Production The performer stands or sits on a high stool facing the keyboard (the performer’s back would be to the camera in the photo on this page). Because the air pressure necessary to sound the pipes is produced by an electric-powered pump, the organ must be plugged into an electrical outlet and the performer must press a button to start the pump. Three sliding metal stop bars are located to the right of the keyboard with which the performer selects the individual rank or combination or ranks to be sounded. These stop bars are mechanically linked to sliders in the slider box. This organ's ranks are labeled: 8-foot Gedeckt (because these are stopped pipes, the eight-foot pipe producing C2 is actually 4 feet in length) with a range from C2 - D6; 4-foot Rhorflote (2-foot stopped pipe producing C3) with a range from C3 - D7; and 2-foot Holtzprincipal with a range from C4 - D8. Using all the fingers and thumbs of both hands to press selected keys, the performer can produce monophonic melodies, polyphonic melodies, block or arpeggiated chords, or harmonized melodies. A selected note sounds only as long as its key is depressed, and its intensity is constant throughout its sounding. The volume of sound produced by this instrument is determined 1) by the number of ranks in operation (the more, the louder) and 2) by the position of the sliding doors on the side panels of the sound chest (the more open they are, the louder the volume). Origins/History/Evolution Small, single manual organs without pedals such as the continuo organ discussed here were in vogue during the 17th century in Europe where they could be used for the accompaniment of entertainments such as chamber operas and chamber music in aristocratic households. Much of the consulted literature on the organ focused on large instruments built into cathedrals for liturgical use, providing less information about the development of smaller, moveable organs. The Baroque era continuo or positive organ on which the instrument pictured here is based was already the product of hundreds of years of development, but the details of this history are overshadowed by the attention paid to the evolution of the much more impressive organs built in cathedrals.