Meditation can lead to vivid sensory impressions as your subconscious mind relaxes and begins to explore and express itself. If you are highly imaginative, the sounds might be mental projections that feel real. When in a trance-like state, your mind can generate auditory perceptions that feel external, even though they originate internally. This is similar to what happens in hypnagogia, which is the Alpha and Theta state between wakefulness and sleep.
The Alpha state (8-12 Hz) is a transitional phase between sleep and wakefulness. This is the most common meditative state where the mind becomes relaxed and calm while still being awake. The brain waves become somewhat slower, and your senses become more heightened. The Theta state (4-8 Hz) dominate when the mind is in a deeply relaxed or in a meditative state, which often is linked with creativity, vivid imagery, and access to the subconscious and the astral plane, and deep psychic experiences.
This happened to me as well when I was new to meditation and trance states. Over time, this phase will pass, and you may develop the ability to discern whether it is contact from spiritual entities or presences on the astral plane, or simply your mind echoing thoughts or impressions. It's important to remember that our minds are complex and often amplify certain sensations or impressions, which can feel especially vivid when our senses are heightened during deep meditative states.