# cutoffFrequency

> Cutoff frequency in hertz for the low-pass filter.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.3/script-reference/unityengine.md)
* **Assembly:** UnityEngine.AudioModule

```csharp
public float cutoffFrequency { get; set; }
```

### Remarks

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 [\_lowpassResonanceQ](/engine/6000.3/script-reference/unityengine/audiolowpassfilter/lowpassresonanceq.md) 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](/engine/6000.3/script-reference/unityengine/audiolowpassfilter/customcutoffcurve.md).

### Examples

```csharp
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);
    }
}
```