Intrigued by the dreamy eyes of the Ustad (master), Mrs. Annie Besant had once inquired of one of Ustad Abdul Karim Khan's disciples whether the Ustad was addicted to any drug. The answer came, "It is the intoxication of music that you see in his eyes, he does not touch alcohol or any such thing."

It is also said that at one of his concerts at Calcutta, listeners were awe-struck at one time when they saw Khan Saheb sitting between the tambouras (drone string instruments), his mounth open but were not able to hear his voice at all. Soon they realized that his tuneful voice had blended indistinguishably with the drones. He had cultivated this special voice production technique through years of early morning mandra-sadhana (practice of lower notes) for several hours and he kept this up even when he was at the top of his fame. This unparalleled control over his voice enabled him to produce the long unbroken unique meends (glides) which allowed him to enrich his music with the tantkari-ang of the Been (Veena) and Sarangi. His unique voice culture also allowed him to maintain the same volume, weight and color of voice in the lower, middle and upper octaves. This coupled with the soul-wrenching emotional element of his music gave his music the divine quality. Whatever he rendered, whether a Khayal, Thumri, Hori or Bhajan, the rendition was always of deeply inward nature. It was probably the Ustad Badal Khan of Calcutta, one of the seniormost musicians of his time, who had remarked, "Abdul Karim's voice has reached its ultimate in tunefulness. If at any time it is not in tune with your instruments or the harmonium, it is your instrument which is at fault; his voice is flawlessly tuneful." Another senior musician of his time had remarked, "he is blessed with unique effect through his voice by the Pir (holy man) whom he worships."