Recognising an efficient music producer in Kolkata, or anywhere else for that matter, involves evaluating several factors. Here are some key indicators to consider:

1. Quality of Work: An efficient music producer will consistently produce high-quality music that meets industry standards. Listen to their previous productions to gauge their level of professionalism, creativity, and technical skill.

2. Portfolio: A strong portfolio showcases the producer's versatility, experience, and ability to work across different genres. Look for a diverse range of projects that demonstrate their expertise.

3. Industry Reputation: Check for reviews, recommendations, and testimonials from artists, record labels, or other professionals in the music industry. A good reputation is often a reliable indicator of an efficient producer.

4. Technical Skills: A proficient music producer should have a solid understanding of music theory, sound engineering, and production techniques. They should be adept at using various digital audio workstations (DAWs) and production software.

5. Communication and Collaboration: Effective communication is essential for a smooth workflow between the producer and the artists. Look for someone  responsive, collaborative, and able to understand and execute the artist's vision.

6. Creativity and Innovation: An efficient music producer should bring fresh ideas to the table and be willing to experiment with new sounds and techniques. Look for producers who are innovative and can elevate the artist's music to new heights.

7. Network and Connections: A well-connected producer often has access to valuable resources such as session musicians, recording studios, and industry contacts. They can help artists connect with other professionals and opportunities within the music industry.

8. Work Ethic and Professionalism: A reliable producer will be organized, punctual, and dedicated to delivering projects on time and within budget. They should also be professional in their dealings with clients and collaborators.

By considering these factors, you can better identify an efficient music producer in Kolkata or any other location. Additionally, personal recommendations and word-of-mouth referrals from fellow artists or industry insiders can also be valuable sources of information.