When the recording is played, can the speakers be heard?
The first issue in audibility, is whether all of the participants can be heard. This is not the same as whether the words are intelligible. If the words spoken by one or more of the participants can be heard, those words are audible. Words that are not capable of being heard because the speaker is too far away from the recording device, or because the person speaks too softly, are not audible. Words that cannot be heard are marked as I/A (inaudible) in the transcript.
Who interprets the words, terms and phrases used by the Conversants?
Often, the State will have an informant or a cooperating defendant who will help the State break the code used in the conversations. In the context of an audibility hearing, this is typically not an issue, although it can become one if the interpretation of the code being used will aid in deciding whether the code is audible. As an example, the words spoken by a conversant appear to be a nonsensical series of words, that appear to be slang or slurred words. If the application of the interpretation provided by the State will provide a framework to make the words 'audible', or otherwise recognizable, then the code becomes relevant to the audibility determination. What the interpretation is, is itself not relevant to this determination, but would become relevant if the focus shifted to relevancy.
Should the Defendant be Present?
Absolutely. The defense of these types of cases requires the lawyer to completely understand the relationship of the words, terms and phrases spoken during the conversation. Having the defendant whose communications were seized listen can allow the defense to preview the State's case with the client, to determine whether the apparent conclusions being asserted by the State are accurate. A possible danger occurs if the defendant tries to vocalize their objections to the communications. If the defendant is not careful, they can let the State know of a defective conclusion, which allows the State an opportunity to re-evaluate their conclusions, and refine the prosecution theory as to the relevance of the conversation.