| 摘要 |
<p>The cavities of the two earphones are interconnected by two tubes (3, 4) of different lengths, the longer of which is preferably of labyrinth or spiral form. The longer tube may have two diaphragms which provide a central length of tube, which is filled with a gas in which the velocity of sound is lower than in air, e.g. carbon dioxide. The ends of the tubes may terminate in the cavities, or the ends of one or both tuber may terminate in the cushions of the earphones or extend through the cushions. The sound quality at each earphone is modified by a delayed resonance or echo effect received via the tubes from the other earphone.</p> |
