Comments on IR-measurement - Home Theater Forum and Systems - HomeTheaterShack.com

 
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post #1 of 4 Old 06-04-11, 10:23 AM Thread Starter
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Jonas hansen
 
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Comments on IR-measurement

I am trying to setup a HF-driver with compression driver/horn and a LF enclosure with a single 15". (JBL ScreenArray speakers). I am really confused about what I'm getting. I have measured the HF/LF individually, and get the measurement below:



I would say that the drivers are out of phase? I have tried a simple "speaker pop test" with an iPhone app (dont know how accurate this is) and it says that both drivers are in phase..

Comments are appreciated!

EDIT: Forgot to mention... I am measuring from the listening position.. Is this wrong? (The results are the same in the LP and in front of the spaekers though)

Last edited by Jonas_h; 06-04-11 at 10:28 AM.
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post #2 of 4 Old 06-04-11, 12:46 PM
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Re: Comments on IR-measurement

They do look to have opposite phases from that plot, but best measuring fairly close to the drive units to reduce the room influences and get a clearer picture.
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post #3 of 4 Old 06-04-11, 02:04 PM
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Re: Comments on IR-measurement

Hi Jonas and John,

Given the time scale we can seen at the bottom of the graph, can't we think that there is only a small delay (maybe a difference of distance between each speaker and the mic) ?

From my point of view, I would read 0.75 ms of delay that is to say 25 cm further for the red speaker (a little bit less of 1 foot).
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post #4 of 4 Old 06-04-11, 02:30 PM
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Re: Comments on IR-measurement

The question over polarity comes from the opposite signs of the peaks, the blue curve having a positive peak but the red curve negative.
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