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Old 27th January 2014, 07:46 PM   #1
JAV is offline JAV  Denmark
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Default Measuring problems

Hi guys.

I've some problems with my new mic/Behringer 8000 with Clio 10FW.
I've measured three tweeters (R29, D30 and SB29). The pattern/peaks are the same every time.

Here of the SB29 - mls and sinusoidal.

What causes this ? Any thoughts ?
Thx.

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Old 27th January 2014, 08:04 PM   #2
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I'm not familiar with Clio, I'm wondering whether you are getting feedback. Also strange that there is such a big difference between swept sine and MLS (they should be almost identical).

Check your sound card settings and make sure that what you are recording is not being sent back out to the speakers (often a tick box called something like "record without monitoring").

You could try downloading holmimpulse and see whether you are getting similar issues, this will give you an idea as to whether it is a hardware or software issue.

Tony.
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Old 28th January 2014, 05:26 PM   #3
JAV is offline JAV  Denmark
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Hi Tony.

Thanks for your feedback. I've tried different soundcard/Clio-mic settings in the software with no succes.
I do not understand the big differents between the measurements.

Whatever is measured in the sinusoidal mode, does obviously occurre in the MLS to.
But i've no clue what causes it.

Any respons is most appriciated. I've written to audiomatic and awaiting some feedback from them.
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Old 29th January 2014, 12:58 AM   #4
RNMarsh is online now RNMarsh  United States
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How were the tweeters mounted for measurement?

-RM
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Old 29th January 2014, 04:15 AM   #5
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Both results are ghastly. S/N ratio based on LF content is non existent.

What are you driving tweeter with?

Have you verified that microphone isn't defective?

What are you using for preamp?

Is phantom power even turned on?
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Old 29th January 2014, 06:45 AM   #6
VaNarn is offline VaNarn  Australia
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The phantom power from the Clio system is 8.2 V which suits the Clio Mic-01 or 02 microphones.The Behringer needs a 15 V or higher D.C. supply and most likely needs the addition of a suitable preamp to work with the measuring system.
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Old 29th January 2014, 02:37 PM   #7
JAV is offline JAV  Denmark
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Thanks for your respons, guys.

Marsh -> He is pic with the D30 mounted in the speaker:

Click the image to open in full size.

Barley -> What do you mean by "driving the tweeter with" ? No, i've not yet verified if the mic is defekt. I'm not using an amp - as far as i understand, i can just use the internal amp with Clio 10FW. So Output-> XLR/crcocodile is directly connected to the tweeter. In the manual it says, it's no need to use the 12V input, when i'm using firewire 6pin/6pin cable.

VaNarn -> Oh my.. what kind of supply, would work with the mic and my Clio ? Bare with me :-)
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Old 29th January 2014, 03:02 PM   #8
Sonce is offline Sonce  Macedonia
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Quote:
Originally Posted by JAV View Post
I'm not using an amp - as far as i understand, i can just use the internal amp with Clio 10FW.
No, Clio 10FW do not include amplifier which can drive loudspeakers directly. You must use CLIO QCbox model 5 power amplifier, or any hi-fi amplifier capable of several W output.
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Old 29th January 2014, 04:28 PM   #9
1audio is offline 1audio  United States
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Are you doing ground plane windowed measurements? The measurement window looks wrong per your plots. You are getting input from reflections and possibly ambient noise.

Getting the right supply voltage for the mike is important,especially for its sensitivity calibration. Also the preamp may misbehave if the suply is too low. Using clipleads to connect a mike signal will also capture lots of emi which you don't want.

This stuff is never as simple as it looks.
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Old 29th January 2014, 05:57 PM   #10
VaNarn is offline VaNarn  Australia
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I should have noticed that your output level window was set at 1 V.This indicates that you are driving your speakers for a frequency response level sweep using the control box without an amplifier,i.e. you have a series resistor added to the speaker impedance,forming a voltage divider.You will need an amplifier and a kit based on a LM3875 i.c. (or similar) would be suitable for this application.Also a precaution when testing tweeters ,is to open the 'settings' dialogue box,the yellow symbol with the two ticks (on the line ,to the right of the green start arrow) and alter the L.F. limit from the 10 Hz setting to say,500Hz. For phantom power an 18V supply can be made from two 9V batteries ,plus a switch ,but they and the wiring must be shielded from EMI and RFI.

Last edited by VaNarn; 29th January 2014 at 06:07 PM.
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