AFMG Network Forum

grodriguez · Member

First of all, I have not used the coverage cones often in the past. However, I was just doing a comparison between coverage shown from a cluster while editing the room (using the 3dB coverage cones at 1kHz) and coverage shown while mapping (direct SPL at 1kHz). There is a significant difference, with the coverage area smaller in the mapped view. Why is there a difference? Again, I have not used the coverage cones often in the past. And what are users primarily using the coverage cones for...basic loudspeaker aiming?

Thank you.

ChrisH · Member

Hi

In answer to your question, I believe there may be two reasons you might need to consider:

The 3dB coverage is based on the polar response of the speaker model, i.e. the -3dB points, then the cone is extrapolated from that. The cone does not take into account the increased loss in SPL with distance to the audience area that will occur off axis from the speaker compared with on-axis. Obviously these variations can be far greater if the speaker is at an angle to the audience area, rather than facing straight down towards it.

Also remember that the coverage cones only project onto faces, so the actual coverage map of direct SPL on an audience area above a face will show more variation than the 3dB coverage area shown on a face below it. To overcome this you can temporarily copy the face to the same height as the audience area and look at the coverage cone on that face.

regards
Chris