Shepard Tone Reference

Return the construction and perceptual limitation of the Shepard-tone pitch-class illusion.

Description

Shepard tones use octave-spaced components and amplitude weighting to emphasize pitch class while obscuring register.

Shepard tones use octave-spaced components and amplitude weighting to emphasize pitch class while obscuring register. Apparent endless motion is a perceptual effect.^[1]

Return the construction and perceptual limitation of the Shepard-tone pitch-class illusion.

When to use Shepard Tone Reference

Use this tool to return the construction and perceptual limitation of the Shepard-tone pitch-class illusion.

Choose a supported reference topic, run an input-free reference with an empty object, or prepare the measured values and caller-supplied test records requested. Keep acoustic metrics, frequency, units and test conditions consistent.

How to use Shepard Tone Reference and understand its results

Choose a supported reference topic, run an input-free reference with an empty object, or prepare the measured values and caller-supplied test records requested. Keep acoustic metrics, frequency, units and test conditions consistent.
Enter topic using the field table and calculation rules, then run the tool.
Read source, statement, topic. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
topic	Reference topic to return.	string; one of "construction", "endless-scale", "caution"	Required

Choose an exact topic enum from the input table and run the lookup. The implementation selects a fixed local entry and returns source, statement and the selected topic. Matching is case-sensitive without trimming or free-text search.

result=stored entry for selected topic

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
source	Source used for the reference statement.	string
statement	Narrow reference statement for the selected topic.	string
topic	Selected reference topic.	string; one of "construction", "endless-scale", "caution"

json

{
  "input": {
    "topic": "construction"
  },
  "output": {
    "source": "Roger Shepard, 1964",
    "statement": "A Shepard tone combines octave-spaced components under a fixed spectral envelope so pitch class is emphasized while absolute register is ambiguous.",
    "topic": "construction"
  }
}

Limitations and assumptions

No waveform is synthesized and no physically unbounded frequency is generated. The source is a stored bibliographic label, not a fetched document; statements are not refreshed at runtime.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Speech-to-Song Reference: Return the repetition-based speech-to-song illusion and its limitations. For a complementary task, use Octave Illusion Reference: Return the two-channel pattern and localization cautions of Deutsch’s octave illusion.

References

Shepard Tone Reference — tool.io

Similar or alternative tools

Speech-to-Song Reference
Return the repetition-based speech-to-song illusion and its limitations.
Octave Illusion Reference
Return the two-channel pattern and localization cautions of Deutsch’s octave illusion.