Page 237 - Electromechanical Devices and Components Illustrated Sourcebook

Chapter 11 Acoustic Devices 199

Horn Loaded
Tweeter Grill Points Head Loop

Wooden Cabinet
Cast Aluminum
Cabinet Height
Adjustment
Midrange
Grill Points Earpiece
Tweeter
1/4" Phone
Woofer Plug
Woofer
Cable

Figure 11-24 Headphones
Figure 11-21 Two- and Three-Driver Loudspeaker Cabinets

an adjustable head loop, as shown in Figure 11-24. Headphones
are particularly applicable in applications that have very low
signal strength and in environments that have high ambient
Capacitor
Inductor noise.

Microphones
Audio Signal Input Woofer Tweeter
Much like loudspeakers, but to a lesser extent, microphones
also play an important part in our lives. The most noteworthy
applications are our telephones. However, the sound repro-
duced by loudspeakers is almost entirely dependent on micro-
Figure 11-22 Two-Way Passive Crossover Schematic phones. Without them, music couldn’t be recorded, newscasters
couldn’t do their jobs, walkie-talkies would be of no value, and
sporting events would be a lot more difficult to follow.
Figure 11-25 shows a sectional view of a basic carbon
microphone. This is one of the oldest microphone designs still
Stereo sound reproduction systems are designed to provide
a spatial sense or depth to the listing experience. This is
accomplished by using a two-channel reproduction system, as
shown in Figure 11-23. Careful attention must be paid to the
placement of the speakers and the acoustics of the room to
properly reproduce a stereo signal.
Another common application for loudspeakers is head- Schematic Symbol
phones. In this case, one or two small drivers are mounted on

Terminals

Left Right Diaphragm
Speaker Speaker
Granulated
Carbon
Mouthpiece Moving
Plate

Stereo
Amplifier Cup
Flexible Wire

Listening
Position Terminal
Figure 11-23 Stereo Sound Reproduction System Figure 11-25 Carbon Microphone