Auralisation
Train Noise Expert allows the calculation of audio files for auralisation at various receiver locations. Auralisations can be made for ‘standstill’ or under train pass-by conditions.
Auralisation calculations are performed for each situation by selecting in the menu ‘Project’ > ‘Run auralisation calculation’. The results of an external noise calculation must first be loaded. Train Noise Expert will prepare the calculation input files for each situation. The calculation procedure will then be called for each situation in turn.
The progress of the calculation is shown in the run log. Please note that complex models could take a few minutes per situation to calculate.
Once the calculations have completed, the audio files will be available for listening via additional controls on the receivers in the results view:
Auralisation controls in the results view
Calculation flowchart
The auralisation calculation procedure is performed for each receiver in accordance with the following diagram:
or use supplied narrowband base spectrum| B1[Base FFT spectrum] A2[Geometry from model] --> B2[Calculate Doppler shifting for each time chunk] B1 --> C[Doppler shifted FFT spectrum in time chunks] B2 --> C C --> D[Apply spectrum envelope from results
for each 1/3 oct band] D --> E[Final FFT in time chunks] A1 --> D E --> |Convert FFT chunks to WAV data|F[Final source waveform] end F --> |Sum all source waveforms|G[Total waveform at receiver] G -->|Apply normalisation|H(WAV file of total sound at receiver)
Note that the default auralisation process assumes that sounds are composed of random noise in 1⁄3 octave bands. Whilst this works well for many noise sources, the results may be less realistic for sources with a significant tonal content. For tonal sources, a narrowband data file can be supplied for a more accurate base spectrum.