What makes the sound?
We hear sounds our entire life, whether they’re from nature or man made. Sounds like birds chirping, dogs barking, a baby crying or a car going by are just some examples. When we go to the movie theater, we also hear sounds, but they’re not real or are they?
Sound reproduction has come a long way. Analog is where it all started. The Victrola for example, converted vibrations from a needle playing on a record sending them to a diaphragm, which in turn pushed them to a cone amplifying the sound. Later vacuum tubes would be used to electronically amplify the sound and put it through a speaker. In today’s world, everything is now digital. It’s virtually perfect, but it still goes through a speaker. So how does a speaker actually work?
It’s quite a bit more sophisticated than the days of the Victrola. It all starts with an electronic signal sent from an amplifier via wires to the speaker. The signal first enters the voice coil, which is simply a coil of copper wire that is suspended inside a permanent magnet located on the back of the speaker. The voice coil is attached to the speaker cone, which is suspended within a frame. The signal from the amplifier causes the voice coil to move in and out, which in turn causes the speaker cone to move in and out pushing air and creating pressure (sound) waves that reach our ears as the sounds we hear.
Today’s speakers use a variety of modern materials. Speaker frames can be stamped steel, die-cast aluminum or plastic. Speaker cones can be made of paper, plastic, aluminum, titanium or even carbon fiber. The enclosures that hold speakers have become smaller and more efficient and may be made of wood or durable plastic. Computerized acoustic modeling has optimized speaker design, enabling speakers to perform at a much higher level. The advent of Class D digital amplifiers in combination with speaker technology, have made sound reproduction virtually perfect. So, that sound you just heard could very well be real. Here’s a great video on how speakers make sound. Have an awesome day.