Long-term environmental noise monitoring with day/evening/night analysis
Current LAeq
dB(A)
Running Lden
Exceeded 10% of the time
Median level
Background noise floor
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Environmental noise is a major public health concern, with the World Health Organization (WHO) identifying it as the second largest environmental cause of health problems after air pollution. Long-term exposure to elevated noise levels increases the risk of cardiovascular disease, sleep disturbance, cognitive impairment in children, and chronic annoyance. Effective environmental noise management begins with accurate, standardized measurement, and that is exactly what the Lden metric provides.
Lden (day-evening-night weighted sound level) is the primary metric specified by the European Environmental Noise Directive (2002/49/EC) for assessing long-term noise exposure. It divides the 24-hour cycle into three periods: day (07:00–19:00, 12 hours), evening (19:00–23:00, 4 hours), and night (23:00–07:00, 8 hours). A 5 dB penalty is applied to the evening period and a 10 dB penalty to the night period, reflecting the greater sensitivity to noise during rest and quiet hours. SonaVyx calculates Lden in real time as: Lden = 10·log10((12·10^(Lday/10) + 4·10^((Levening+5)/10) + 8·10^((Lnight+10)/10)) / 24).
In the United States, the EPA and FAA use Ldn (day-night average sound level), which combines a 15-hour daytime period (07:00–22:00) and a 9-hour nighttime period (22:00–07:00) with a 10 dB night penalty. Unlike Lden, there is no separate evening penalty. SonaVyx supports both EU and US period definitions, selectable with a single toggle. The HUD/FAA threshold of 65 dB Ldn is widely used for land-use compatibility around airports.
The WHO Guidelines for Environmental Noise (2018) strongly recommend that outdoor Lden should not exceed 53 dB for road traffic, railway, and aircraft noise. For nighttime, the recommendation is that outdoor Lnight should not exceed 45 dB. SonaVyx compares your measurements against these thresholds in real time, providing immediate feedback on whether the noise environment meets WHO recommendations.
ISO 1996 (Parts 1 and 2) is the international standard for describing, measuring, and assessing environmental noise. Part 1 defines basic quantities including LAeq (A-weighted equivalent continuous sound level), statistical levels (LN), and rating levels with adjustments for tonality, impulsiveness, and time of day. Part 2 specifies measurement methods for outdoor and indoor environments. SonaVyx implements the core measurements specified in ISO 1996, including LAeq integration, statistical percentiles, and event detection.
Environmental noise monitoring with SonaVyx is valuable for multiple use cases: pre-construction baseline surveys to establish existing ambient levels, construction site monitoring to demonstrate regulatory compliance, traffic noise assessment along residential streets, venue and event noise management, and personal research to understand the acoustic quality of your living environment. While professional noise surveys require Class 1 instrumentation per IEC 61672, SonaVyx provides a free screening tool for preliminary assessment and awareness.
Lden (used in Europe per Directive 2002/49/EC) has three periods: day (12h), evening (4h, +5 dB penalty), and night (8h, +10 dB penalty). Ldn (used in the US by EPA/FAA) has two periods: day (15h) and night (9h, +10 dB penalty) with no separate evening penalty. Ldn is typically 1–2 dB lower than Lden for the same noise environment.
A true Lden requires a full 24-hour measurement covering all three periods. However, shorter measurements of individual periods can provide useful LAeq values. For regulatory noise mapping, the European Directive requires long-term averages typically computed over a calendar year from representative measurement campaigns.
These are statistical noise levels. L10 is exceeded 10% of the time and represents intrusive noise events (like passing vehicles). L50 is the median level. L90 is exceeded 90% of the time and represents the residual background noise. The UK uses LA90 as the background noise indicator (BS 4142), while traffic noise indices in many countries reference LA10,18h.
The WHO 2018 guidelines recommend Lden below 53 dB based on systematic evidence linking higher levels to increased risk of ischaemic heart disease. Above 53 dB Lden, the relative risk of cardiovascular effects increases by approximately 8% per 10 dB. Night noise above 45 dB Lnight is linked to sleep disturbance and adverse metabolic effects.
Yes. SonaVyx accumulates data continuously and uploads measurements in batches. Ensure your device stays awake (disable sleep/screen timeout) and keep the browser tab active. For extended monitoring, connect your device to a power source. Note that some browsers may throttle background tabs; keeping the SonaVyx tab in the foreground ensures consistent capture.
SonaVyx compares each 1-second LAeq sample against a running 30-second average. When the current level exceeds the average by more than the sensitivity threshold (adjustable from 3–20 dB), an event is logged with its type (spike, impact, or sustained), peak level, and duration. Lower sensitivity settings will catch more subtle events; higher settings focus on significant exceedances.