AudioSource.spread

Description

Sets the spread angle (in degrees) of a 3d stereo or multichannel sound in speaker space.

0 = all sound channels are located at the same speaker location and is 'mono'. 360 = all subchannels are located at the opposite speaker location to the speaker location that it should be according to 3D position. Default = 0.

using UnityEngine;

public class Example : MonoBehaviour
{
    // when any AudioSource goes trough this transform, it will set it as 'mono'
    // and will restore the value to 3D effect after exiting
    // Make sure the audio source has a collider.
    void OnTriggerEnter(Collider other)
    {
        AudioSource audio = other.GetComponent<AudioSource>();

        if (audio)
        {
            audio.spread = 0;
        }
    }

    void OnTriggerExit(Collider other)
    {
        AudioSource audio = other.GetComponent<AudioSource>();

        if (audio)
        {
            audio.spread = 360;
        }
    }
}