Preferences

The Preferences window, opened from the toolbar button or Tools → Preferences, provides access to options for data display and calculation. It has the tabs Graphics, Graphics sizes, Advanced, Parabolic equation, Normal modes, Ray tracer, Misc., Exporting and Sound levels display. The solver tabs are described on the Advanced Solver Options page.

Graphics

• Max bathymetry graphics data (pixels): Limits the amount of bathymetry data sent to the graphics card. For large bathymetry data sets, graphics display may become slow; lowering this value reduces the graphics load while the full bathymetry data is still used for calculations.
• Smooth results colours: Blends the colour scale between levels instead of drawing discrete bands.
• Cross-section options: Show full water depth in cross-section, Show land in cross-section and Truncate land in cross-section control what the cross-section view includes.
• Hide probes on image export: By default, probes are not included in exported images. Uncheck this to include them.
• Draw not surveyed area: By default, dBSea draws unsurveyed (no-data) areas of the bathymetry in a separate colour. Uncheck this to leave them transparent.
• Levels display: Three ways of displaying calculated levels:
  1. Max from all depths projected to surface: The maximum sound level at each x and y location across all depths is displayed at the water surface.
  2. Single depth: Data from one depth layer is displayed at that depth. The layer is chosen with Display solution depth # and the + / - buttons, which are also available on the Probes page.
  3. All depths: All depth layers are drawn.

Graphics sizes

• Vertical graphical scaling: Controlled by the Depth scaling and Land height scaling sliders. Redrawing the graphics after adjusting these sliders may take some time.
• Other sliders: Results opacity, Source size, Probe size, Moving source line width, Results contours line width and Results contours darkening.

Misc.

• Units: You can switch between metric and imperial units.
• Project name: You can enter a name for the project.

Exporting

• Export settings: Choose whether to include a logo image and a text caption in exported image files. Delimiter to use in CSV export sets the field delimiter for text exports of levels: comma (default), semicolon, tab or space. ESRI ASCII exports always use a space, and the probe page’s clipboard copies always use a comma.

Sound levels display

• Level type for display: For frequency-domain scenarios the options are Sound pressure level dB SPL (Leq), Sound exposure level dB SELcum @ T0 = 1s (LE) and Max sound pressure level dB SPL 1s; for time-series scenarios they are Sound exposure level dB SELcum, Peak sound pressure level dBpeak (Lp) and Peak to peak sound pressure level dB SPLpkpk. SPL and SELcum can be switched freely after a solve; changing to or from Max sound pressure level, or between the time-series types, requires a re-solve. The SELcum and peak types are the ones used for assessments against the criteria in the Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (NOAA, 2016 and later updates).
• Assessment period for results (s): Used for converting between level types (e.g., from input sound sources given as SL to output levels as dB SELcum). Setting it also sets the assessment period of every source. It is disabled when a scenario contains a moving source, because the assessment period is then the duration of the longest source motion. Continuous sound sources are active throughout the assessment period, unless modified by the Count and Duty % parameters.