Audio enhncement can give back more life like sound to audio tracks.   Dynamic expansion and impact restoration make music more live like   performance. Most recordings inherently been compressed for technical   reasons. Sometimes audio bandwith is limited especially in the bass   range. Ther is a lot of inherent energy in the bass range. So most   recording engineers limit the amount bass in the recording.

          There processes that can enhance musical experience in a recording.   Dynamic expansion and impact restoration is a analog process that can   give a more more life like sound. Equalization can restore the more bass   enegy back into the audio track. Equalization is is done digital audio   domain.