As you can see, we need at least two voices. Person 1 recite 1th voice, and person 2 recite 2nd voice. It is not yet exactly 'jazzed', because there is not real sincopa, which is a 'trade mark' of jazz, but we have some more complex rhythm and metric form. 

When lot of people recite, then they use various pitches of voices, and because of that, sometimes, or very often, we can hear something as bells or similar. This phenomena comes from something called harmonics, or aliquotes. Those are tones (some kind of sub-tones) already existing in some tone. (So one tone is never just 'one'.) Depending from shape of room, space where they are performed, they can sounds different. It also depends from shape of bodies of people who are reciting, and theirs registers of voices. 

Sometimes, when and if, members are musical, daimoku, or gongyo, can sound extremely beautiful (from musical standpoint), because they instinctively puts their voices in harmony and make an entire accord (sometimes very complex).