Double-Slope Decay Screen
Compare positive early and late decay-rate magnitudes against an explicit fractional-change threshold.
Description
A decay curve with different earlier and later slopes may indicate more than one decay process.
A decay curve with different earlier and later slopes may indicate more than one decay process. This screen compares already fitted positive decay magnitudes.1
The returned values include Fractional rate change, Late-to-early rate ratio, Double-slope candidate. The How section below explains the calculation, input rules and interpretation.
When to use Double-Slope Decay Screen
Use Double-Slope Decay Screen when you need to evaluate the supplied records under the calculation and evidence rules below. No slope fitting, double-exponential model or statistical evidence of coupled decay is produced.
Choose the measured quantities, units, weighting and measurement basis before entering values. For a reference, select the exact topic. For a catalog lookup, prepare complete source-backed records; for a screen, select an applicable caller limit.
How to use Double-Slope Decay Screen and understand its results
- Choose the measured quantities, units, weighting and measurement basis before entering values. For a reference, select the exact topic. For a catalog lookup, prepare complete source-backed records; for a screen, select an applicable caller limit.
- Enter earlyDecayDecibelsPerSecond, lateDecayDecibelsPerSecond, minimumFractionalChange using the field table and calculation rules, then run the tool.
- Read fractionalRateChange, lateToEarlyRateRatio, doubleSlopeCandidate. 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 |
|---|---|---|---|
| earlyDecayDecibelsPerSecond | Early decay-rate magnitude (dB/s) | number; minimum: 0 | Required |
| lateDecayDecibelsPerSecond | Late decay-rate magnitude (dB/s) | number; minimum: 0 | Required |
| minimumFractionalChange | Minimum fractional change | number; minimum: 0 | Required |
Enter finite positive earlier/later magnitudes and a finite nonnegative fractional-change threshold. Return a positive finite ratio, absolute fractional change and inclusive flag. A zero threshold flags even identical slopes.
ratio=laterMagnitude/earlierMagnitude; change=abs(ratio−1); flagged=change≥threshold Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| fractionalRateChange | Fractional rate change | number; minimum: 0 |
| lateToEarlyRateRatio | Late-to-early rate ratio | number; minimum: 0 |
| doubleSlopeCandidate | Double-slope candidate | boolean |
{
"input": {
"earlyDecayDecibelsPerSecond": 30,
"lateDecayDecibelsPerSecond": 15,
"minimumFractionalChange": 0.25
},
"output": {
"fractionalRateChange": 0.5,
"lateToEarlyRateRatio": 0.5,
"doubleSlopeCandidate": true
}
}Limitations and assumptions
No slope fitting, double-exponential model or statistical evidence of coupled decay is produced.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing fields without a declared default, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use EDT and Late-Decay Reference: EDT is derived from the initial 0 to -10 dB decay slope and extrapolated to a 60 dB decay time; it emphasizes the early subjective decay. This reference explains the selected concept and the evidence needed to interpret it. For a complementary task, use Coupled Room Volume Screen: A coupled-room geometry screen summarizes a secondary-room share and the connection opening per combined room volume. These ratios can guide investigation before detailed acoustic modeling.
References
-
Double-Slope Decay Screen — tool.io
Similar or alternative tools
- EDT and Late-Decay Reference
EDT is derived from the initial 0 to -10 dB decay slope and extrapolated to a 60 dB decay time; it emphasizes the early subjective decay. This reference explains the selected concept and the evidence needed to interpret it.
- Coupled Room Volume Screen
A coupled-room geometry screen summarizes a secondary-room share and the connection opening per combined room volume. These ratios can guide investigation before detailed acoustic modeling.