One very interesting aspect of Rahman is his preference for untrained voices. Rahman says “a defect in the singing adds a human touch.”Rahman uses many different voices in a film, irrespective of whether they suit the character or not just for variety. He thinks otherwise things would get monotonous. He says, “There was a time when the album of an Indian film would have only two voices. Today different singers sing for the same character. The times have changed. The attention span of the average listener has decreased and his geographical purview has broadened. The listeners no longer think in terms of perfect or imperfect. They want different voices, standards be damned.”

Rahman is well known for experimenting in the music. He introduced several new, relatively unknown and professionally untrained voices into the mainstream playback. He has shown an extraordinary flair for experimenting with untrained voices. Singers, who have worked with him, have repeatedly said that Rahman’s open approach during recording sessions has spurred them on to giving their best.

Suresh Peters, Nabron Ghosh, Shahul Hameed, GV Prakash, Noel James, Yugendran, Blaaze, Aslam Musthafa, Sukhwindara Singh, Srinivas, Shankar Mahadevan, Soorjo Bhattacharya, Devan, Harini, Anupama, Sunitha Sarathy, Madhushree, Sujatha Trivedi, Reena Bharadwaj, Mahalakshmi Iyer, Richa Sharma, Poonam Bhatia, Shoma Banarjee, Dominique, Minmini, Shubha, Febi, Hema Sardesai are just few of the singers who have thrived after the advent of Rahman.

Singers like Hariharan, Asha Bhonsle, Sujatha, Unnimenon have had successful comebacks in the industry after working with Rahman. Unnikrishnan, Bombay Jayshree and Nithyashree Mahadevan who are successful Carnatic classical vocalists also have been introduced into film playback by Rahman.Another attention-grabbing characteristic of Rahman is his wide use of singers from different languages. He used singers like Udit Narayan, Sukhwindara Singh, Madhushree and many other North Indian singers in Tamil; and in addition to this, he also used Tamil singers in Hindi. This was done on experimental basis, and greatly appreciated by his fans too.

He experiments not only with his singer’s voices, but also with different kinds of sounds in music. His songs expose very different kinds of sound, which makes one easily identify his songs among other music director’s songs. His experiments with untried and unusual sounds are noticed since his very first venture, ‘Roja’. The music of his film ‘Kadhalan’ was totally experimental, which had very exceptional, outstanding and brilliant compositions like ‘Mukkala Muqabala’, ‘Oorvasi Oorvasi’, ‘Gopala Gopala’, ‘Ennavalae Ennavalae’, and ‘Pettai Rap’. All these songs had something fresh and innovative in them. This album was appreciated worldwide by even non-Tamilians.

Speaking about experiments with sounds, Rahman tells, “Experimenting with different sounds in music is a real joy. Yes, people accept experiments, but musicians should know the limits of experimenting too. Even experimenting has its boundaries. People cannot take in experimentation in every other composition. So as a musician, I think that it is good enough to wait until people are ready to digest new kind of compositions, and when they are, then take the compositions out from bag.”