Audio recording devices range from tape-based recorders such as micro, mini, and standard audio cassettes and reel-to-reel tape recorders, to digital audio recorders that record on compact discs, hard drives, and media cards.

For this reason, if the original is in a digital format, any copies need to be made in a comparable digital format that uses lossless compression. Preferably, the recording method used to duplicate the original would have no compression at all.

If only the audio recording itself is received in discovery, critical information can be missed that might reside on the audio recording device itself, such as the time and date the device was set to when the recording was made.