Tutorial · About 10 minutes

Your First Prediction

We'll run one complete prediction together — from a blank map to reading a convergence zone. Follow along in the app; every step says what you'll see. By the end you'll understand the whole flow, and every other feature is a variation on it.

Before you start. Nothing here needs a subscription or a connection — the free, offline engine runs this whole tutorial. We'll use a deep-water spot in the North Pacific (20° N, 150° W) as a worked example because it shows convergence zones nicely, but any deep location works.
§01

Place your source

  1. Open the map
    Launch MuirWave and open the Underwater Acoustics page. The movable cursor you see is the Probe — MuirWave's default. It scouts conditions; it doesn't run a prediction on its own (more on the Probe vs Source split).
  2. Switch to an acoustic scenario
    Tap the acoustic-scenario button ("place a source and receiver"). This drops your acoustic Source — the thing making noise — and a receiver onto the map.
  3. Position the Source
    Drag the Source to our example position, roughly 20° N, 150° W — open ocean, well away from the coast. As you settle it, MuirWave pulls the seabed depth, sediment and sound-speed profile for that spot; the bottom-right readout shows the water depth beneath you.
The Underwater Acoustics page: the chart, the Probe panel reading conditions at the cursor, and the panel rail down the right side.
Figure 1. The Underwater Acoustics page. The Probe panel (left) reads conditions under the cursor — seafloor type, wind, ambient noise, depth; the panel rail runs down the right; the bottom-right shows the seabed depth and its data sources. (Here the Probe sits in deep water; you'll drop a Source next.)
§02

Describe your source

  1. Set the frequency
    Use the frequency slider to choose your source's frequency — try 1 kHz to start. The slider is a smooth log scale from 10 Hz to 50 kHz, so you can set any value, not just fixed steps.
  2. Set the depths
    Set the source depth — how deep the source sits (say 50 m) — and the receiver depth you're listening at. Depth strongly affects which ray paths form.
  3. Set the source level
    Set how loud the source is (its source level). This is the "how loud it starts" term of the sonar equation.
MuirWave assumes no defaults. It waits until you've actually set the frequency, both depths and the source level — it marks which inputs are still needed — and only then runs the prediction. That's why the results appear the moment your scenario is complete, not before.
§03

Read the ray paths

  1. Open the Ray Path plot
    The Ray Path view draws how sound leaves your source and curves through the water — a cross-section from the source outward.
  2. Spot the convergence zone
    Follow the rays: they spread, thin out into a shadow zone, then refocus into a convergence zone (CZ) where sound is loud again. MuirWave marks the first CZ and its range.
  3. Try the field view
    Switch the plot to FIELD (or BOTH) to see the same information as a continuous picture of where sound reaches. New to this? See Concepts → rays & convergence zones.
The Ray Path plot: the sound-speed profile on the left, and a fan of rays leaving the source that bend downward, thin out into a shadow zone, then refocus range after range at convergence zones — with caustic markers along the seabed.
Figure 2. The Ray Path plot (RAYS mode). The sound-speed profile sits on the left; the ray fan leaves the source, bends down and thins into a shadow zone, then refocuses at each convergence zone — the gold caustic markers along the bottom flag where rays refocus. Here the water is deep enough that CZs recur every ~8 nm.
§04

Read the answer

  1. Check Depth Excess
    In the Profile panel, the Depth Excess readout tells you whether the water is deep enough for reliable CZ propagation — and colours itself green / yellow / grey accordingly (what the colours mean). In our deep-water example it should be healthy.
  2. Read detection / transmission loss
    The readouts show how the sound weakens with range and how far it stays detectable. This is the sonar equation resolved for your scenario.
  3. Change one thing & watch
    Drag the frequency up to 10 kHz and watch the prediction change — higher frequencies are absorbed faster, so ranges shrink. This live feedback is the fastest way to build intuition.
That's a complete prediction. You placed a source, described it, and read how its sound travels and how far it carries — all offline, from public-domain ocean data.
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Where to go next

NEXT

Estimate impact ranges

Turn your prediction into an assessment — how far the source could affect marine life, against regulatory thresholds.

Open the recipe ›
UNDERSTAND

The concepts, explained

Why sound bends, what transmission loss really is, and where convergence zones come from — in plain language.

Read the concepts ›
DO MORE

All the how-to recipes

Regional packs, working offline, the methodology export, changing units, and unlocking Live & Pro.

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