Spectral decay measures the rate at which spectral energy decreases over time within an analysis window. It is computed as the time constant of an exponential fit to the energy envelope of successive frequency bins, or equivalently as the difference between early and late spectral energy summed across frames. Parameters include the analysis frame size, window function, frequency bin resolution, and decay fitting method. Persisted through standardized audio analysis algorithms and widely implemented in libraries such as Librosa, Essentia, and MATLAB Signal Processing Toolbox. [formal: decadentia-spectralis | substrate: mind | horizon: a moment | explicit: yes | epoch: 0.01]
Accepted ontology entry
spectral-decay
Spectral decay measures the rate at which spectral energy decreases over time within an analysis window. It is computed as the time constant of an exponential fit to the energy envelope of successive frequency bins, or equivalently as the…
Definition
Why it is in scope
A mathematical audio feature that measures the rate at which spectral energy decreases over time within a frame or analysis window. Human-made, used for attack detection, percussive sound classification, and instrument identification. Persisted through algorithms, teaching, and standard audio processing libraries.
Names and aliases
- spectral-decayen · CANONICAL
Relations from this entry
- cmsqglbgv00763e32jisx8hz3INSTANCE_OF →
Spectral decay IS a specific kind of spectral feature — it characterizes the temporal evolution of a signal's spectral energy distribution. A competent speaker calls it 'a spectral feature.' The removal test is irrelevant for INSTANCE_OF; the kind-hierarchy test passes: spectral decay is a member of the class of spectral features, which are numerical descriptors extracted from a signal's spectrum.
- cmsq4obya07m0jlssh92wv3v0DEPENDS_ON →
Spectral decay operates on spectral energy values extracted from a spectral representation. Remove spectral representation and spectral decay has no input data to operate on — the feature cannot be computed. Present-tense constitutive dependency, not historical association.
- cmsop0xz702e7jlssmzq3gk17DEPENDS_ON →
Spectral decay measures the rate at which spectral energy decreases over time. It operates on spectral data — remove the concept of spectrum and there is no spectral energy to measure, no spectral domain in which decay is defined. The removal test passes: no spectrum concept = spectral decay is undefinable.
- cmspcwtqk04tkjlsslitlqy58DEPENDS_ON →
Spectral decay measures the rate at which spectral energy decreases over time. It operates on the power spectrum — remove power spectrum and there is no spectral energy measure on which decay can be computed. The removal test passes.
Relations to this entry
No accepted relations in this direction.
Record identity
- Created
- Aug 14, 2026, 4:48 AM UTC
- Content hash
- 8377f84b9bee12a9fb014ab5c9632b929afe74874a97b48806681301f5307e9f