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Concept module

Pitch, Frequency, and Loudness / Intensity

Keep one compact sound bench while separating pitch from frequency, loudness from amplitude and an amplitude-squared intensity cue, and probe delay from the source sound itself.

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Starter track

Step 2 of 50 / 5 complete

Sound and Acoustics

Earlier steps still set up Pitch, Frequency, and Loudness / Intensity.

1. Sound Waves and Longitudinal Motion2. Pitch, Frequency, and Loudness / Intensity3. Beats4. Doppler Effect+1 more steps

Previous step: Sound Waves and Longitudinal Motion.

Also in Waves.

Start from track beginning

Why it behaves this way

Explanation

Pitch and loudness should not be treated as the same sound property. In this bounded sound bench, pitch follows frequency: higher frequency means more cycles each second and a shorter period. Loudness follows amplitude and the strength of the energy-transfer cue, so a larger amplitude can sound louder without changing pitch.

The medium speed stays fixed so the page can separate the ideas cleanly. Raising frequency makes the compression pattern repeat faster and sit closer together, while raising amplitude makes the parcel motion larger and raises the amplitude-squared intensity cue.

Key ideas

01Pitch tracks frequency, not amplitude.

02Loudness or intensity tracks amplitude and a stronger energy-transfer cue.

03A sound can be higher pitch without being louder, or louder without being higher pitch.

Frozen walkthrough

Step through the frozen example

Frozen walkthrough

These checks read the same sound bench the stage and graphs use, so the algebra stays tied to one live wave.

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Frozen valuesUsing frozen parameters

For the current sound wave with $v_{w a v e} = 2.4 m/s$ and $f = 1.1 Hz$ , what wavelength and period go with that pitch?

v_{w a v e}

Wave speed

2.4 m/s

f

Frequency

1.1 Hz

λ

Wavelength

2.18 m

T

Period

0.91 s

1. Use the sound timing relations

Use

λ = \frac{v _{w a v e}}{f}

and

T = \frac{1}{f}

2. Substitute the live values

λ = \frac{2}{.} 41.1 = 2.18 m

and

T = \frac{1}{1} .1 = 0.91 s

3. Interpret the pitch cue

A frequency of 1.1 Hz means the source repeats 1.1 cycles each second, so pitch is set by timing while the spacing becomes 2.18 m.

Current pitch timing

λ = 2.18 m, T = 0.91 s

The frequency sits in a middle range here, so the pitch cue is moderate and the cycle timing is neither especially slow nor especially fast.

Common misconception

A taller sound wave must have a higher pitch because the wave looks bigger.

Amplitude changes how strong the motion is, not how many cycles happen each second.

Frequency changes pitch. Amplitude changes the bounded loudness / intensity cue.

Mini challenge

You want the same pitch but a louder sound. What single change should you make?

Make a prediction before you reveal the next step.

Decide whether to raise amplitude, raise frequency, or move the probe farther downstream.

Check your reasoning against the live bench.

Raise amplitude.

Keeping pitch the same means keeping frequency fixed. Raising amplitude increases the loudness / intensity cue without changing pitch.

Quick test

Misconception check

Question 1 of 3

Use the live sound bench, not memory alone. These checks separate pitch, amplitude, and the bounded loudness cue.

Which change raises pitch without changing the loudness cue?

Use the live bench to test the result before moving on.

Accessibility

The simulation shows a horizontal sound tube with a source piston, parcel markers, a movable probe, and a colored compression ribbon. Optional overlays mark motion direction, compression spacing, and a bounded energy-transfer cue.

Changing frequency changes how quickly the sound repeats and how closely the compression pattern is spaced. Changing amplitude changes the parcel swing size and the linked intensity cue.

Graph summary

The first graph compares source and probe displacement over time so pitch stays tied to frequency and period.

The second graph compares the probe shift with the local compression cue.

The third graph shows the bounded intensity cue as a function of amplitude.

Keep this idea moving

Open the next concept, route, or track only when you want the current model to widen into a larger branch.

Hear superpositionOscillations

Pitch, Frequency, and Loudness / Intensity

Sound and Acoustics

Explanation

Step through the frozen example

For the current sound wave with vwave​=2.4m/s and f=1.1Hz, what wavelength and period go with that pitch?

Which change raises pitch without changing the loudness cue?

Keep this idea moving

Beats

Doppler Effect

Wave Interference

For the current sound wave with $v_{w a v e} = 2.4 m/s$ and $f = 1.1 Hz$ , what wavelength and period go with that pitch?