Figure A


Speaker orientation can be an important factor in classrooms and meeting rooms in particular. As indicated in Figure A, there is a difference of about 10 decibels (dBA) in speech levels between the front and back of the speaker. This amounts to about 1-1/2 decibels per 30 degrees of rotation from the head on direction of the speech signal.

The average sound level of a male speaker is about 64-65 decibels at a distance of 3 feet from the speaker. The average speech level of a female speaker is about 2-4 decibels lower at a 3-foot distance from the speaker.