TRUE OR FALSE
  • Most modern loudspeakers are based on a concept that has nothing to do with creating sound.
  • The bass reflex loudspeaker design uses a sealed enclosure to create low frequencies from a small loudspeaker cabinet.
  • Loudspeakers haven't changed significantly since 1925.
  • If you have an amplifier and speaker system delivering 100 dB to a listener, then add a second identical amplifier/speaker system, the listener will only hear 103 dB — not 200 dB.

 

ANSWERS

1. TRUE. In 1874, Ernest Siemens filed a U.S. patent for a “magneto-electric apparatus” for “obtaining the mechanical movement of an electrical coil from electrical currents transmitted through it.” Three years later, he attached a parchment cone to the moving coil, and patented the moving coil transducer, which was then able to create audible sound.

2. FALSE. A bass reflex design uses a ported or vented box, which uses some of the energy generated by the rearward motion of the loudspeaker cone to create a limited band of low-frequency energy through a tuned port (or vent). The size of the enclosure and the air mass escaping through the port defines the low-frequency content produced by it.

3. FALSE. The concept by which loudspeakers function is fundamentally the same since the days of Siemens (electro-magnetic motor structure and moving diaphragm), but there have been ongoing dramatic improvements and variations since then. Most modern improvements are based on materials and construction techniques that reduce distortion and enhance frequency response, power handling, and efficiency.

4. TRUE. The reason is that decibels are a non-linear representation of the summation of powers based on the way we hear. The watts will double, but the decibels won't.