Echo delay in ms. 10 to 5000. Default = 500.

	// Set the delay on the chorus filter to the max working value.
	@script RequireComponent(AudioSource)
	@script RequireComponent(AudioEchoFilter)
	function Start() {
		GetComponent(AudioEchoFilter).delay = 5000;
	}

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(AudioSource))]
[RequireComponent(typeof(AudioEchoFilter))]
public class Example : MonoBehaviour {
    void Start() {
        GetComponent<AudioEchoFilter>().delay = 5000;
    }
}

import UnityEngine
import System.Collections

[RequireComponent(typeof(AudioSource))]
[RequireComponent(typeof(AudioEchoFilter))]
public class Example(MonoBehaviour):

	def Start() as void:
		GetComponent[of AudioEchoFilter]().delay = 5000