For anyone who would like the enemy to be able to hear you, place the script on your enemy.

EnemySoundListener.cs

///////////////////////////////////////////////////////////////////////////////
// 
// This code is licensed under MIT license.
// 
// Copyright © 2026 Bil Simser, https://www.simstools.com
//
// Permission is hereby granted, free of charge, to any person obtaining a copy 
// of this software and associated documentation files (the "Software"), to 
// deal in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is 
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in 
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
///////////////////////////////////////////////////////////////////////////////

using UnityEngine;
using UnityEngine.Events;

///////////////////////////////////////////////////////////////////////////////
///
/// For anyone who would like the enemy to be able to hear you, place the script on your enemy. 
/// soundSources is your player prefab (hero player), and other things that produce sounds. 
/// OnSoundHeardEvent specifies what should happen when the enemy hears you. 
///
///////////////////////////////////////////////////////////////////////////////
public class EnemySoundListener : MonoBehaviour
{
    [SerializeField] private GameObject[] soundSources;
    [SerializeField] private float hearingDistance = 10f;
    [SerializeField] private float hearingAngle = 90f;
    [SerializeField] private UnityEvent onSoundHeard;

    private AudioSource[] soundSourceAudios;

    private void Start()
    {
        soundSourceAudios = new AudioSource[soundSources.Length];
        for (int i = 0; i < soundSources.Length; i++)
        {
            soundSourceAudios[i] = soundSources[i].GetComponent<AudioSource>();
        }
    }

    private void Update()
    {
        if (CanHearSound())
        {
            Debug.Log("Heard sound!");
            onSoundHeard.Invoke();
        }
    }

    private bool CanHearSound()
    {
        if (soundSources == null || soundSources.Length == 0)
        {
            return false; // No sound sources assigned, cannot hear anything
        }

        foreach (var soundSourceAudio in soundSourceAudios)
        {
            if (soundSourceAudio == null)
            {
                continue; // Skip null audio sources
            }

            if (!soundSourceAudio.isPlaying)
            {
                continue; // Sound source audio is not playing
            }

            Vector3 directionToSoundSource = soundSourceAudio.transform.position - transform.position;
            float angleToSoundSource = Vector3.Angle(transform.forward, directionToSoundSource);
            if (directionToSoundSource.magnitude <= hearingDistance && angleToSoundSource <= hearingAngle / 2f)
            {
                // Sound source is within hearing distance and angle
                return true;
            }
        }

        return false;
    }
}