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Two-period Leq
Combine sound levels measured over two consecutive periods using their time and sound energy.
First period level (dB SPL): -20–160; Second period level (dB SPL): -20–160; First period time share (%): 0–100
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Two-period Leq
First period level (dB SPL): 100 Second period level (dB SPL): 90 First period time share (%): 50
- Equivalent level Leq (dB SPL)
- 97.403627
- First period energy share (%)
- 90.909091
With w = first time share / 100, Leq = 10 log10(w × 10^(L1/10) + (1 − w) × 10^(L2/10)). First energy share = 100 × w × 10^(L1/10) / total energy. Each input must be a constant level or that period’s Leq, measured with matching calibration, reference and frequency weighting. The two non-overlapping periods must cover the whole duration; their actual durations cancel in the ratio. A 0% period contributes no energy. This is an energy mean across time, not an arithmetic dB mean or simultaneous-source sum. Energy share is not perceived loudness share. Only A-weighted inputs produce LAeq. No exposure dose, legal compliance or safe listening time is calculated.
Methodology
How it works
With w = first time share / 100, Leq = 10 log10(w × 10^(L1/10) + (1 − w) × 10^(L2/10)). First energy share = 100 × w × 10^(L1/10) / total energy. Each input must be a constant level or that period’s Leq, measured with matching calibration, reference and frequency weighting. The two non-overlapping periods must cover the whole duration; their actual durations cancel in the ratio. A 0% period contributes no energy. This is an energy mean across time, not an arithmetic dB mean or simultaneous-source sum. Energy share is not perceived loudness share. Only A-weighted inputs produce LAeq. No exposure dose, legal compliance or safe listening time is calculated.
Method and assumptions documented by Techrider.live
2026-11-07
Frequently asked questions
Can I enter two momentary meter readings?
Only if each level represents its entire period. For changing sound, use the measured Leq of each period with the same frequency weighting; isolated peaks cannot represent the energy over a period.