Long-term recordings comprise many hours of raw data. For the preliminary check, i.e. the question of whether and where a full analysis is required, we use a tool we developed ourselves. Its scope and its limits are described below.
Mika Wihanto
July 2026
A remote measurement over several days produces recordings many hours long. At the outset, the real question is not “how high is the rating level” but: Is there anything in this recording at all that justifies a full analysis? And if so: where?
We developed our own tool for exactly this step.
Load the file, narrow down the measurement section, run the calculation, and finally export what goes into the report.
Raw signal and level history over the whole file. The measurement section is set with sliders or by entering seconds, so conspicuous passages can be targeted directly.
One-third-octave spectra as LTerz,eq and LTerz,Fmax, plus the level histories LAF, LCF and LZF with parameter bars.
One-third-octave levels against the hearing threshold and the reference values for day and night, with the 95 % tolerance. This is the actual preliminary check.
Running one-third-octave display during the measurement, useful for checking on site whether setup and level range are right before recording for days.
The tool accompanies a long-term measurement from recording to report. Even during the measurement, the live view shows level and one-third-octave spectrum, so setup and level range can be checked on site. Afterwards, it visualises the level history of the entire recording, narrows down conspicuous sections and compares their one-third-octave spectra with the hearing threshold and the reference values according to DIN 45680. The checklist guides through the individual steps, and the export provides graphics as SVG and a report marked as a preliminary check as PDF and HTML.
The program does not do the expert work for us; it only shows where a closer look is worthwhile. Reviewing the recordings, comparing them with the noise log, dealing with extraneous noise and assessing according to the regulations remain careful expert work and take their time.
Commercial analysis software covers this range of functions and usually goes beyond it. However, it is designed for the already narrowed-down measurement data set, not for finding it.
There is also a technical reason: anyone who implements the calculation chain themselves, i.e. A- and C-weighting, FAST time weighting, one-third-octave filtering and energy averaging, sees exactly where the results are sensitive to the choice of parameters and boundary conditions.
An interactive demonstration of the interface with synthetic data can be found on the Remote Measurement page in the section “Our own analysis software”. It reproduces the workflow but does not calculate with real recordings.