Who is the Self that we meditate on?

Is it the Self by which we see, hear, smell, taste and through which we speak?
Is Self the mind by which we perceive, understand, know, remember, will, desire and love?
These are but servants of the true Self who is pure awareness.

This Self is everything in everything.

People who realize this eternal Self, called Brahman, live in joy and go beyond death.

Aitareya Upanishad