Findings Concerning Speakerphone Privacy

The call was placed on speaker at 2:15pm.

The motive: the person needed both hands for something else. Or they wanted to show the other person something on screen. Or the ear gets warm after a long call.

When the call went to speaker, the voice dropped.

The Forensic Finding

The voice dropped because speaking into a phone held at ear level feels private. The mouth is close to the microphone. The voice is directed at the phone. Other people in the space are aware of the call but are not receiving it at full clarity.

When the phone is placed in front of the speaker and the voice drops, the person is instinctively matching the privacy level of the ear-held call. The dropped voice communicates: this is still a conversation between two people.

The speaker is broadcasting the dropped voice to everyone in the room.

The Arithmetic

Normal conversation volume: approximately 60 decibels. Voice level during speaker call: approximately 48 decibels. Speaker output at the adjacent location: approximately 55 decibels.

The person's lowered voice, filtered through the phone's microphone and amplified by the speaker, reaches the adjacent person at roughly the same level as a normal conversation. The adjacent person receives the call clearly.

The person on the call also receives a clearly lowered voice, which may prompt them to ask "can you speak up?"

The Outcome

The call was audible to three people in the room. All three received information about: a project status, a name, and an opinion about someone's approach that was not meant for them.

The voice was lowered throughout. This was noted.