public void setVolume(float volume) {
        if (volume < 0 || volume > 1)
            throw new IllegalArgumentException("Volume must be between 0 and 1");

        this.volume = volume;
        this.updateNeeded = true;
    }
Sets the gain of the High-Pass filter.

@param volume The gain value (0.0 to 1.0).
jme3-core/src/main/java/com/jme3/audio/HighPassFilter.java