this isn't an actual spell, but it might help, it has helped me before. direct you energy around you and outside your body, but still close. Focus on the energy around you, senses such as hearing or sight may be improved to a point where you can see and hear spirits,
A spell will not immediately give a person a strong ability such as this. The list of psychic abilities are things many people can practice. Some people notice one without trying, and practice it because they've noticed it. But some people exercise something deliberately, having not previously experienced it.
Some of it comes down to belief, but it all dtarts with meditation. A quiet mind will better hear the silent ripples.
That all said, you may find a spell or ritual meant to target that aspect. Like I said, though, you will not automatically have a strong ability. It will still take practice.
To be fair though spells are nothing more than meditations with a purpose. So by that logic a meditation to improve an aspect of psycho-awareness could be called a spell.
While I have no direct experience in clairaudience, or necromancy of any sort, I imagine the first step would be to simply meditate on what it is you are trying to accomplish in the first place. Getting to understand things from an experience perspective can be much better than learning by following instructions. Read up on some necromancy spells, get an idea of what goes into communing with the dead and once you feel like youve gathered enough info, experiment.
You don't need a spell for this. You need practice.
Meditate regularly.
Work on opening your chakras.
Practice cleansing yourself.
Practice cleansing your room.
Practice cleansing objects.
Practice charging yourself, your room, and your objects.
Keep in mind some people never become clairaudient. Get the basics down, and then go from there.