The Perceived Harmonics Experiment invites visitors to explore how a single pure tone may be experienced during focused listening. While only one fundamental frequency is intentionally generated, some listeners may perceive additional tones, subtle pulsations, shifts in pitch, or changes in spatial awareness.
This interactive experiment is designed as an exercise in careful observation rather than expectation. Visitors are encouraged to listen at a comfortable level, note what they actually perceive, and compare any secondary tone with the harmonic relationships of the original frequency.
The purpose is not to assume the source of these perceptions, but to create a structured environment in which auditory experience can be observed, compared, and better understood.
The sequence is simple:
Experience - Observe - Record - Reflect - Export
Perceived Harmonics Experiment
Listening Beyond the Fundamental
Set a Comfortable Listening Level
111 Hz pure sine tone
Select Play Sound Check to hear the tone. Adjust your device and the control below until the tone is clearly audible and comfortable. Louder is not better.
Focused Listening
111 Hz pure sine tone
Choose a listening period. When you are ready, select Start Listening. Listen without searching for a result; simply observe whether the tone remains singular or whether another auditory perception appears.
The Continue button becomes available only after a timed listening session finishes naturally or is manually stopped after it begins.
What Did You Perceive?
Report the experience without interpreting its cause.
Select every description that applies to your listening session. If the tone remained singular, choose Single tone only. Otherwise, choose one or more observations that best match what you noticed.
Approximate the Secondary Tone
Match what you remember hearing without interpreting the result.
The fundamental used in your listening session was 111 Hz. Move the slider toward the approximate pitch you perceived. Moving the slider alone produces no sound.
Use a comfortable level established during the Sound Check. The comparison tone uses the same experiment volume setting.
Compare the Mathematical Relationship
Your pitch estimate compared with the 111 Hz fundamental.
Relationship
Complete Pitch Matching to calculate the nearest simple mathematical relationship.
Interpretation Note
This comparison evaluates the frequency you selected against simple harmonic or reciprocal ratios of 111 Hz. A close match does not establish that an additional physical frequency was present in the original sound; it describes the mathematical relationship of your reported perceptual estimate.
Test What You Heard
Compare the original 111 Hz fundamental with your remembered secondary tone.
The two tones below are played separately and only when you choose them. First replay the original 111 Hz tone, then replay your selected comparison tone. Use the same comfortable volume established during the Sound Check.
Does the comparison resemble the secondary tone you perceived?
This is a subjective verification step. It does not change your original observation or the mathematical analysis.
Review Your Experience
Preserve what you observed before assigning meaning to it.
Session Complete
Your observations remain within this browser session unless you choose to download them. Nothing is transmitted or stored externally by this particle.
PDF is intended as a readable personal session record. CSV preserves the same observations in a standardized format for comparison or research use.