The statement must be spontaneously made while the person was perceiving (i.e. contemporaneous with) the event or condition, or "immediately thereafter."
The permissible time lapse between event and statement may range from seconds to minutes, but probably not hours.
Under the Federal Rules of Evidence [FRE 803(1)],[1] a statement of present sense impression is an exception to the prohibition on use of hearsay as evidence at a trial or hearing, and is therefore admissible to prove the truth of the statement itself (i.e. to prove that it was in fact cold at the time the person was speaking, or to prove that the person was indeed traveling very fast).
The basis for this exception is the belief that the statement is likely reliable and true, as there is no time for reflection, distortion, or fabrication.
Upon proper authentication, that portion of the audio-recording containing descriptions or explanations of the shooting is admissible as present sense impression.