unity - Timing a sound effect

Why does this not work? I'm trying to get the sound effect before the visual, but I don't hear it until I move away from the location. This is part of a routine that is called from Update on the Player. Thanks in advance for any hints.

    if (carriedObject.name == "HandTorch") {
        float d =findNearest (o.transform);
        if (d < 0.5f) {
            ASource.clip = woosh;
            ASource.Play ();
            float duration = woosh.length;
            StartCoroutine (WaitForSound (duration));
            o.transform.Find("Flame").gameObject.SetActive(true);
            o.transform.Find ("MyTorch").gameObject.SetActive (true);

        }
    }
}

public IEnumerator WaitForSound(float duration)
{
    yield return new WaitForSeconds(duration);
}