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Show Device Aids Electric Organ to Atece Use Of Its Own Echo CHICAGO. A device no larger than a golf bag, which makes it possible for the electric organ to create and utilize its own echo, provides a modern substitute for the reverberation provided by the stone walls and high vaulted ceil- , ings of large cathedrals. Official name of the unique device de-vice is the Hammond reverberation reverbera-tion control. And its sole function, according to engineers, is produc tion of the echoes which alone assure as-sure full organ performance. Explaining the use of reverberation reverbera-tion control, organ experts point out that echo is present in varying degree in all music and 'in most sound, being that part of sound which reaches the listener's ear by reflection from neighboring surfaces, sur-faces, rather than by straight air line. Because early churches mainly main-ly were large and solidly constructed, con-structed, most people ' naturally learned to prefer organ music with considerable echo, they add. Need of the echo-maker became acute when some churches built their acoustics especially for speech a situation that is not the best for musical reception. It also provides the only way in which real organ music can be secured out-of-doors, since the absence of walls would otherwise mean the absence of reverberation re-verberation and even the largest organ would sound thin and shrill. The reverberation unit takes the place of nature's own echo by picking pick-ing up a part of each tone signal Irom the organ console and carrying carry-ing it through a mechanism that delays each sound. The delayed signals sig-nals are amplified and sent on to join the original unaltered electrical impulses or signals. What the ear then hears Is the original music as played by the organist followed quickly by its echo or reverberation, just as in a building part of the music reaches the listener directly and part of it Is reflected from walls and ceiling and reaches the ear later than the original music. The length of the reverberation time Is also controlled by the unit, this being an important factor In producing a natural-sounding echo. Some churches have a reverbera-tio reverbera-tio as low as three seconds and other large churches run up to 11 seconds. |