Acoustics and Loudspeakers Trivia Quiz

Answer: True

Within this range, the human ear is the most sensitive to 1000 Hz and 5000 Hz. Our hearing range decreases as we age, even if we take care of our hearing, because the "hairs" in the cochlea (inner ear) wear out over time. Fletcher and Munson were the first people to measure people's range of hearing.

Answer: False

At 140 dB we reach our threshold of pain; so that's why when we go to a rock concert, the music physically hurts if you are relatively close to the speakers. Sound at 90 dB or more can cause progressive hearing loss. As a frame of comparison, usual talking is 70 dB, a chainsaw is 110 dB, a rock concert is 140 dB and a rocket engine is 180 dB.

Answer: Magnet, voice coil, spider, cone, pad ring, basket

A magnetic field is generated around the voice coil by applying voltage which causes it to vibrate in an up and down motion. When a positive voltage is applied to the positive side of the voice coil the speaker will move outward. If that field is opposite of the magnet it will pull the cone down.

The higher the voltage, the more the cone will move. So if you turn up the volume too much on your speaker it will lock the cone, or overheat, and destroy the speaker.

Answer: Ultrasonic

Frequencies above 20,000 Hz are too high to be heard by humans but some animals, such as dogs, can hear above the human range. Ultrasonic sensors are sometimes used in vehicles to sense if fingers are in the way of a closing sliding door on SUV's. Frequencies below 20 Hz are too low to be heard by humans. Since children hear better than adults, they can hear more subtle sounds like the humming of florescent lights.

Answer: Woofers, subwoofers, tweeters

Drivers look like cones or horns and have surfaces which move back and forth to make the sound. If you remove the front screen from your speaker, you will see the driver. Tweeters handle the treble frequency range above 2,000 Hz, midrange speakers handle 200 Hz to 2,000 Hz and subwoofers handle the bass range below 200 Hz. The combination of these speakers gives a full, rich sound.

Answer: True

Lower speed vibrations produce low frequency sound and high speed vibrations produce higher frequency sounds. Low frequency sound is harder to stop so it can travel a much further distance. That's why when you hear a rock concert from a distance you hear the boom of the bass sound but not the higher frequency sound.

Answer: True

Ringing in the ears or tinnitus comes from damage to the microscopic endings of the hearing nerve in the cochlea (inner ear). Over time the hairs in the inner ear wear down and break off causing permanent hearing loss.

Answer: True

Sound exerts pressure on the ear, and exposure to a loud sound such as an explosion creates pressure intense enough to permanently damage the ear and can cause complete and permanent hearing loss.

Answer: Paper, cloth, polypropylene, aluminum

The unfortunate effect of using paper is that time, dampness, pests and abuse take their toll and damage the material. A very lightweight material needs to be used for the cone so that the speaker does not have to "drive" as hard to vibrate the voice coil/spider assembly.

Heavier materials cause the speaker to work harder to produce sound which results in heat. Recently, new materials have been tested that are less environmentally sensitive such as Mylar, laminated polyester, butyl rubber, and even neoglass (woven glass-fiber material).

Answer: It keeps the shape of the speaker and is a heat sink

The basket of the speaker is in a shape similar to a bowl which allows maximum air flow so that the speaker does not over-heat. It is rigid and helps keeps all the elements of the speaker in place.