AudioLowPassFilter.cutoffFrequency

Description

Cutoff frequency in hertz for the low-pass filter.

The cutoff frequency is usually defined by the point on the smooth curve where attenuation hits -3 dB (~0.71) and is also the center frequency where high values of AudioLowPassFilter.lowpassResonanceQ causes a boost. Frequencies at and below this value are gradually much less affected by the filter. A lower cutoff frequency attenuates more high-frequency content. A higher cutoff frequency attenuates less high-frequency content.

The value ranges from 10.0 to 22000.0. The default is 5000.0. Values outside this range are clamped.

Setting this property replaces any custom cutoff curve with a single constant cutoff frequency. To change the cutoff frequency based on distance, use AudioLowPassFilter.customCutoffCurve.

using UnityEngine;

[RequireComponent(typeof(AudioSource))]
[RequireComponent(typeof(AudioLowPassFilter))]
public class LowPassCutoffExample : MonoBehaviour
{
    const float lowCutoffHz = 800f;
    const float highCutoffHz = 22000f;

    AudioLowPassFilter lowPass;

    void Awake()
    {
        lowPass = GetComponent<AudioLowPassFilter>();
    }

    void Update()
    {
        // Mathf.Sin(Time.time) ranges from -1 to 1. Add 1 to get 0 to 2, then multiply by 0.5
        // to get an interpolation factor t in the range 0 to 1 that changes smoothly over time.
        float t = (Mathf.Sin(Time.time) + 1f) * 0.5f;
        lowPass.cutoffFrequency = Mathf.Lerp(lowCutoffHz, highCutoffHz, t);
    }
}