INFLUENCE OF THE HORN ON SOUND RECORDS
of air inclosed by the horn. The quantity and quality of
resonance depends mainly upon the volume of the inclosed
air and somewhat upon its shape. If the walls of the horn
are smooth and rigid, they produce no appreciable effect
upon the tone. But if the walls are rough or flexible, they
may absorb or rapidly dissipate the energy of vibrations of
Fig. 122. Experimental horns of various materials, sizes, and shapes.
the air of certain frequencies and thus by subtraction have
an influence upon tone quality. The horn of itself cannot
originate any component tone, and hence cannot add any¬
thing to the composition of the sound. The horn is an air
resonator and not a soundboard ; any vibrations which the
walls of the horn may have are relatively feeble and are re¬
ceived from the air which is already in vibration, while in
the case of a soundboard, the air receives its vibration from
157