Chapter 07: Acoustic Fundamentals

Sound is defined as:

In transverse waves, the displacement of particles is _____ to the direction of the propagation of the wave.

In longitudinal waves, the displacement of particles is _____ to the direction of the propagation of the wave.

Sound waves are _____ waves.

Sound is also a _____ wave.

For sound to occur, a force must act against _____.

Therefore, sound cannot travel or propagate in a _____.

A sound wave is also defined as a _____ wave.

The three media through which sound can travel are: (check all that apply)

The highest points on this traveling wave are points of _____. (check all that apply)

Sound travels through air at the rate of _____ meters per second (_____ miles per hour).

Sound travels through water at the rate of _____ meters per second (_____ miles per hour).

Sound travels through steel at the rate of _____ meters per second (_____ miles per hour).

Does the fact that sound travels at approximately 770 miles per hour mean that each sound will travel that far?

The distance a sound travels, regardless of the medium it travels through, depends upon its original _____ along with the medium it travels through.

Since the velocity of sound is approximately the same for all wavelengths, frequency is often used to better describe the effects of the different wavelengths. The equation for the relationship between wavelength and frequency is:

The human hearing spectrum is limited, just as the human vision spectrum. The lowest an average person can hear is _____ cycles per second (Hertz).

The human hearing spectrum is limited, just as the human vision spectrum. The highest an average person can hear is _____ cycles per second (Hertz).

Wavelength is defined as:

Frequency is defined as:

The amplitude of a sound describes how much energy the sound has.

Ampltiude and frequency are not independent of each other.

When you softly strike the Middle C key on the piano, you create a sound with a frequency of 256 Hz. When you strike the same key as hard as you can, you have changed the _____.

All letters in the alphabet can be spoken in words with the same amplitude. It’s best to try voicing them all to make sure you get the right answer to this question.

You will see the term ‘compression amplitude’ in the hearing care field because:

The normal hearing organ can detect the sound which moves particles in the air a distance of _____ of a centimeter.

This sound has an intensity of 1 times 10 to the minus 16th Watts per centimeter squared.

This is a mathematical calculation that forms the basis for:

The threshold of hearing is established as _____ decibels.

The term loudness means the same to everyone with normal hearing.

A guitar note may be high pitched to me and _____ pitched to you. Who is right?

As a hearing instrument specialist, you will be giving tests that have subjective and objective components. Objective components are _____ and _____.

Frequency is:

If I strike the Soprano C on the piano, it is measured at about 1024 Hertz and at an amplitude depending on how hard I strike it. Right? Yes. So, you can call it a low, soft, medium loud, fat key, but it’s still _____.

Yet, as you are asked to describe the pitch, you are asked to describe it according to how you perceive it. That makes it _____.

So, frequency is objective and pitch, subjective.

Dynamo, dynamite, dynamic, all refer to the Greek root – Dunamis (Δύναμις). This word means:

The unit of force is the dyne.

Decibels in dynes = decibels [dB] Sound Pressure Level (SPL).

0.0002 dynes per centimeter squared is _____.

50 dB SPL + 50 dB SPL = _____.

For every increase in intensity of 10 dB, the average increase in loudness increases by about _____.

Perceptions of persons with hearing loss may be due to:

This is why you need to be _____ when dealing with subjective explanations.

Threshold are _____ specific.

The term ‘dB in Hearing Level [dB HL]’ is used in hearing testing because the human ear is ‘frequency specific’ sensitive and will naturall amplify sounds within the speech spectrum [1000 to 5000 Hz].

The audiometer is calibrated for differential SPL levels.