In the Search field, search for ‘Waterfall’ and select Ambient_Water_Waterfall.

Right-click the Ambient_Water_Waterfall Blend Container and select Find in Project Explorer > Selection Channel 1.

The waterfall consists of many sounds played concurrently, and so they have all been collected inside the Ambient_Water_Waterfall Blend Container.

With Blend Containers, not only can you group multiple objects and let them play at once, but also define which of the objects should be playing within a certain range of a Game Parameter using crossfades. The Ambient_Water_Waterfall Blend Container contains two waterfall audio structures. One with a mix of various waterfall sounds and the other with a single, fairly compressed Sound SFX.

To create a gradual change from the mix of various waterfall sounds to the single one, you’ll be using Blend Tracks. Let’s now head into the Blend Track Editor and make a new track.

In the Object Tab, select the General Settings tab.

At the bottom of the Object Tab, ensure that Blend Track is selected.

In the Secondary Editor, click New Blend Track.

Name the track to 'LOD'.

To specify which of the child containers you’d like to use in the Blend Track, you need to add them in the Contents Editor.

At the bottom of the Object Tab, click Contents to switch to the Contents Editor.

In the Ambient_Water_Waterfall Contents Editor, drag both children into the LOD Blend Track.

Make sure the Waterfall_Close Blend Container is on top.

In the Blend Track Editor, select Crossfade.

Using the Selector, select the Distance_to_Player parameter, located in Game Parameters > Generic.

You now have a Distance_to_Player cursor in the Graph View, and you can use it to simulate distance by dragging right or left. Let's listen to each container before blending them.

In the Transport Control press play and drag the Distance_to_Player cursor from right to left, and vise-versa.

Notice that the sound is switched from Waterfall_Close to Waterfall_Far once you cross a value of 50 and vise-versa. While the Adventurer approaches the sound, the Waterfall_Far sound should slowly get lower, while the Waterfall_Close sound should get louder. Let’s now design the behavior described above in the Graph View.

Drag the start and end handle until the Waterfall_Far sound covers the distance 25-100.

Make sure the Waterfall_Close start and end handle, covers the distance, 0-60.

In the Transport Control press play and drag the Distance_to_Player cursor from right to left, and vise-versa.

The Waterfall_Close Blend Container will now increase in volume about halfway, but this means that at a distance of 40, 5 voices will be active at once (1x Waterfall_Far voice, along with 4x voices in Waterfall_Close). A level of detail system should gradually increase resource usage when approaching, and so let’s use the Distance_to_Player parameter to control the Voice Limit for the Ambient_Water_Waterfall.

Close the Blend Track Editor, and in the Advanced Settings tab’s Playback Limit group box, select Ignore Parent.

Select the ‘Limit sound instances to’ and make sure the list option is set to Globally.

You’re not going to set a fixed limit here, but instead use an RTPC to gradually change the limit.

In the RTPC tab, use the Y Axis Selector to select Sound Instance Limit.

Use the X Axis Selector to add the Game Parameters > Generic > Distance_to_Player parameter.

Select the leftmost control point and set the Playback Limit (y) to 4.

This will allow all Voices in the Waterfall_Close to play at once.

Select the rightmost control point and set the Playback Limit (y) to 1.