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Old 17th April 2013, 03:21 PM   #1
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Join Date: Sep 2011

I use Holmimpulse to make my time time alignment of my drivers. But today I bought a ECM8000 with an USB interface Tbone micplug. My probleme now is when I do 2 ou 3 measurements of the same driver , the offset is always different. The offset mooves at each measurement. When I use my old mic pluged to the RCA input of my PCI sound card, evething is fine, each measurement has the same offset.

Could someone can help me ?

Sorry for my bad english..................
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Old 17th April 2013, 03:56 PM   #2
tomchr is offline tomchr  Canada
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I'm not sure what you mean by offset. Is the offset in the frequency domain (i.e. SPL measures differently from measurement to measurement) or in the time domain (the pulse response doesn't line up with the previous measurement)?

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Old 17th April 2013, 06:55 PM   #3
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I should have spend more time in english leasson when I was young,,,,,,,,

Yes the probleme is that the time domain,,, the pulse response slide at each measurement,,,,

Have a look on the curves, I write the same offset value on the 3 curves. Of course it's the same driver without moving anything.

When I use my other mic that is pluged to the soundcard, the 3 curves are totally superposed with the same offset value.
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Old 21st April 2013, 10:32 AM   #4
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So nobody uses an usb microphone interface ? here is my interface :

the t.bone MicPlug USB - Thomann UK
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Old 22nd April 2013, 11:12 AM   #5
dkxdn is offline dkxdn  Denmark
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I use a XTZ mic amplifier and that works
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Old 22nd April 2013, 03:29 PM   #6
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So with your XTZ, for exemple if you make 3 times the same measure with homlimpulse of the same driver, the curves are absolutely superposed with the same offset value ?
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Old 22nd April 2013, 03:49 PM   #7
tomtom is offline tomtom  Slovakia
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I had this problem when i was using different sound card for playback and different for recording. Do you use same device?
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Old 22nd April 2013, 04:46 PM   #8
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I've got 2 soundboard, a PCI soundblaster and a Behringer UCA222. They work well if I use a mic with a mic amplifier connected the the input of the card. But if I use the USB mic interface, it doesn't work, the varves never line up.
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