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-   -   CSD measurements in open area ? (http://www.diyaudio.com/forums/equipment-tools/229609-csd-measurements-open-area.html)

Bazukaz 8th February 2013 03:43 PM

CSD measurements in open area ?
 
Hello,

Frequency response measurements look to be more or less acceptable in regular rooms loaded with stuff and using gated signals of course.
However CSD plots seem to be very sensitive to reflections and close positioning of microphone does not help much(because it's a planar speaker).
How far is it needed to be from buildings/forests etc? I understand ground reflection cannot be eliminated but maybe a place with tall grass can help as well as lifting the speaker off the ground?
Any experience with this?

Regards,
Lukas.

tvrgeek 9th February 2013 05:57 PM

Instead of a 30 foot pole, have you tried using the single boundary method as D
'Apolitto suggests for response measurements? You only need a large paved area. Set the mic on the pavement. Then remember you are doing 2 pi not 4 pi measurements. It was mentioned as half a joke, but the other idea is to bury the driver on a small baffle in the ground, and hang the mic a meter or so above it. Again 2 pi. No baffle step, and no close reflections. It should work quite well.

Bazukaz 13th February 2013 02:48 PM

Quote:

Originally Posted by tvrgeek (Post 3362868)
Instead of a 30 foot pole, have you tried using the single boundary method as D
'Apolitto suggests for response measurements? You only need a large paved area. Set the mic on the pavement. Then remember you are doing 2 pi not 4 pi measurements. It was mentioned as half a joke, but the other idea is to bury the driver on a small baffle in the ground, and hang the mic a meter or so above it. Again 2 pi. No baffle step, and no close reflections. It should work quite well.

Hi,

This is quite interesting. The problem I am trying to measure electrostatic speaker which is a dipole so doing that is not possible as the back cannot be covered. Neither a near field measurement can be done like for monopole speakers(Where is that "near field" when a speaker is 0.3x1.5m :) )
The only idea that comes to my mind is to take a car, 12->230V converter and try to find some large open field while placing the speaker 1-2 meters above the ground.

Regards,
Lukas


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