Audio Recordings are admissible as document in Indian Courts, if they fulfill certain conditions as laid down by Apex Court in Ram Singh V Col. Ram Singh AIR 1986 SC 3
a) the voice of the speaker must be duly identified by the maker of the record or by others who recognize his voice. Where the maker has denied the voice it will require very strict proof to determine whether or not it was really the voice of the speaker.
b) The accuracy of the tape recorded statement has to be proved by the maker of the record by satisfactory evidence direct or circumstantial.
c) Every possibility of tempering with or erasure of a part of a tape recorded statement must be ruled out otherwise it may render the said statement out of context and, therefore, inadmissible.
d) The statement must be relevant according to the rules of Evidence Act.
e) The recorded cassette must be carefully sealed and kept in safe or official custody.
f) The voice of the speaker should be clearly audible and not lost or distorted by other sounds or disturbance.
However, with the advancement of technology now the recordings can be on electronic media, in which case Affidavit u/s 65B be required and few other things need to be taken care in case it is recorded during phone conversations, which can be discussed, if the question has more clarity