Wwise Fundamentals

Drag the right side control point down to the bottom.

The result is that regardless of the player’s health, 200 dB of volume will be subtracted from the heartbeat's normal playback level. In most cases, subtracting anymore than 80 dB of volume prevents a sound from being heard, so it’s safe to say that the heartbeat won’t be heard at all.

Double-click the curve at around 50 to create a new control point.

Click the far-left control point, then type 0 into the Y: coordinate, and press Enter.

Now the heartbeat’s volume won’t begin to increase until the player’s health falls below 50.

You can zoom in on sections of the curve using the plus and minus symbols in the lower-right corner of the graph. The icon in between the plus and minus symbols resets the graph view to display the entire curve. You can also use Z+click-drag to zoom in; or use Ctrl+mouse wheel to zoom in and out vertically and Ctrl+Shift+mouse wheel to zoom in and out horizontally. See the Keyboard Shortcuts and Commands available from the Wwise Project menu.

To get a really smooth transition, you could create a lot more control points, but instead, you'll take advantage of the built-in curves.

Right-click the curve anywhere to the right of the control point you just moved and select Exponential (Base 3).

This curve rapidly increases the volume once the health falls below 50 and makes only a gradual increase in the heartbeat’s volume as the player’s health gets closer to 0.

It’s very difficult to know exactly how to set the curve without auditioning how it will sound.

In the Transport Control, play the Heartbeat object. Then in the RTPC tab, drag the PlayerHealth parameter cursor left and right to hear the effect on the sound.

Besides increasing the overall volume of the heartbeat, another way to gradually make the player aware of the heartbeat is to open a low-pass filter. A low-pass filter only lets sounds below a set frequency pass through, which can make it sound muffled. This would be a great way for the player to start to hear the heartbeat. Gradually opening the low- pass filter will make the heartbeat sound more pronounced and obvious. Since Wwise lets you map a single Game Parameter to multiple properties, you’ll add a low-pass filter curve in addition to the volume curve you just created.

Click the next available [>>] selector to map a second property, the Voice LPF, to the PlayerHealth Game Parameter.

You now see two lines. Red lines indicate a volume curve, while blue represents a filter curve.

The Low-pass filter property value can range from 0-100. Think of it as a percentage that indicates what percentage of frequencies will be filtered away, starting at the top of the frequency spectrum. In other words, a value of 20 means the top 20 percent of the audible frequency spectrum will be filtered off making the sound seem not quite as bright or clear. Since the default value is 0, it means that currently there is no change to the audio, and all of the frequencies in the sound can be heard.

	Refer to Associating Low-pass and High-pass Filter Values with their Corresponding Cutoff Frequencies for further details.

Like the volume curve you created, you’ll start with all of the frequencies being filtered away and then, once you get below a certain point, you'll gradually open the filter until all of the frequencies can be heard.

Raise the control point at the right end of the curve to the top. Then double-click the curve near the 60 value to create a new control point. Raise this new control point to the top.

Listen to the heartbeat while you slowly drag the PlayerHealth parameter from the left side of the graph to the right side. Notice the heartbeat is initially loud and clear and becomes softer and more muffled as you approach the center of the graph. From the center to the right, the heartbeat is inaudible.