Calibration Drift Screen
Calculate absolute before-versus-after sound-calibrator drift and compare it with an explicit acceptance limit.
Description
Before-and-after calibrator readings can reveal drift during a sound measurement session.
Before-and-after calibrator readings can reveal drift during a sound measurement session. An explicit acceptance allowance determines the screen.1
The returned values include Absolute calibration drift, Within caller limit. The How section below explains the calculation, input rules and interpretation.
When to use Calibration Drift Screen
Use Calibration Drift Screen when you need to evaluate the supplied records under the calculation and evidence rules below. No calibrator accuracy, microphone correction, measurement uncertainty or protocol-specific limit is supplied.
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 Calibration Drift 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 afterLevelDecibels, beforeLevelDecibels, maximumDriftDecibels using the field table and calculation rules, then run the tool.
- Read driftDecibels, withinCallerLimit. 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 |
|---|---|---|---|
| afterLevelDecibels | After-check level (dB) | number | Required |
| beforeLevelDecibels | Before-check level (dB) | number | Required |
| maximumDriftDecibels | Maximum accepted drift (dB) | number; minimum: 0 | Required |
Enter finite before/after decibel readings and finite nonnegative drift limit. Return finite absolute drift and the inclusive acceptance flag.
drift=abs(after−before); acceptable=drift≤maximumDrift Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| driftDecibels | Absolute calibration drift (dB) | number; minimum: 0 |
| withinCallerLimit | Within caller limit | boolean |
{
"input": {
"afterLevelDecibels": 94.3,
"beforeLevelDecibels": 94,
"maximumDriftDecibels": 0.5
},
"output": {
"driftDecibels": 0.29999999999999716,
"withinCallerLimit": true
}
}Limitations and assumptions
No calibrator accuracy, microphone correction, measurement uncertainty or protocol-specific limit is supplied.
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 Microphone Placement Reference: Microphone height and distance from façades or other reflecting surfaces must follow the stated measurement standard and assessment objective. This reference explains the selected concept and the evidence needed to interpret it. For a complementary task, use Classroom Background-Noise Screen: Background noise in an unoccupied furnished classroom affects listening conditions. A measurement should be compared with an explicitly chosen applicable design limit.
References
-
Calibration Drift Screen — tool.io
Similar or alternative tools
- Microphone Placement Reference
Microphone height and distance from façades or other reflecting surfaces must follow the stated measurement standard and assessment objective. This reference explains the selected concept and the evidence needed to interpret it.
- Classroom Background-Noise Screen
Background noise in an unoccupied furnished classroom affects listening conditions. A measurement should be compared with an explicitly chosen applicable design limit.