High Efficiency Speaker Asylum

Posted by Tre' (P) on October 03, 2011 at 17:30:42

In Reply to: RE: Some people… posted by Iron Knee on October 03, 2011 at 17:15:20

Are you saying that you measure a 6db loss of SPLs for every doubling of distance from you speakers in you listening room?

I find that hard to believe and my ears tell me different. At least with my speakers in my room.

If the microphone, on the Bruel & Kjaer decibel meter, is very directional
that may account for some of what you measure. It might be made for free field use.

"Free-field microphone
• Compensates for the disturbance it causes
• Normally to be used pointed at source (0° incidence)
• If used in reverberant (diffuse)-field, will underestimate SPL
❖ Pressure microphone
• Does not compensate for the disturbance it causes
• Responds uniformly to the actual SPL"

Here's a bit more from Paul,

"I assume you don't listen in an anechoic chamber. In that case, the inverse square law (-6dB per doubling of distance) only applies in the near field; past a certain distance (called the "critical distance") the sound level is dominated by the reverberant field and is independent of location. The critical distance varies depending on room volume and absorption, but for average listening rooms it is about 1 meter. "

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

Edits: 10/03/11   10/03/11