Voice Clarity Enhancement

I need a skilled audio forensics expert to improve the quality of some voice recordings. The recordings currently suffer from background noise, low volume, and mumbling.

Key requirements include:
- Reducing background noise
- Increasing volume levels
- Clarifying mumbled speech

Ideal skills and experience:
- Proficiency in audio editing software
- Experience with audio restoration techniques
- Attention to detail and a good ear for audio quality

Please provide samples of previous work.