Hearing an echo in a dream means that you are going through an emotional struggle or have something weighing on your heart. But if you have multiple copies of the same person appearing in your dream, it means that you have been very close to someone who has passed away and that this person is still with you somewhere deep down.
An echo in a dream could represent something frightening or traumatic that happened during the day. It could also represent something similar or repeating in your waking life, like an event happening over and over again.
The sound of an echo in your dream may also imply that you have a lot to say and that the world needs to hear what you have to say.