ECM8000 microphone measuring techniques and usage discussion - Page 7 - Home Theater Forum and Systems - HomeTheaterShack.com
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post #61 of 170 Old 01-27-09, 12:00 PM
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Re: MobilePre ECM8000 oddities

Quote:
from zero, or from first impulse received?
In the IR window popup (after the measurement is complete), I set 1msec in the Left Pre-Window and 5msec in the Right Post-Window, and then Apply to the measurement.

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post #62 of 170 Old 01-27-09, 03:28 PM
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re: ECM8000 microphone measuring techniques and usage discussion

The one from the DBX RTA-M usable thread http://www.hometheatershack.com/foru...ion-curve.html

Here is a screenshot:

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post #63 of 170 Old 01-27-09, 05:37 PM Thread Starter
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Re: MobilePre ECM8000 oddities

Okay, my results:
Red = Maggie, Vertical Mic
Green = Maggie, Horizontal Mic
Orange = Adire, Vertical Mic
Blue = Adire, Horizontal Mic

Attachment 11936

Gates were 6 ms, "Split" ECM8k cal file, 12" from tweeter on axis. 1/2 octave smoothing. Shifted to line up like curves.

You can see the trademark split between horizontal and vertical orientation of the mic in both sets of curves.

However, most notably, the Adire HE10.1 does not show the fall-off that the Magnepans show. Very interesting. I stared with a bad assumption and look where it got me

So at least now I have renewed confidence in the mic and soundcard, but less in the Magnepans
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post #64 of 170 Old 01-27-09, 05:45 PM Thread Starter
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Re: MobilePre ECM8000 oddities

So, it looks like the New ECM cal file, horizontal orientation is the best for direct measurements.

Behringer insists that vertical is better for diffuse field measurements like pink noise and such, but since 90% of my measurements are drivers and speakers directly, I will stick with horizontal.
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post #65 of 170 Old 01-27-09, 06:05 PM
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Re: MobilePre ECM8000 oddities

Yeah, I think we can assume the ECM and the cal file are fine.

The Maggies still go fairly high, and unless your hearing is really top notch, I doubt you'd be disappointed in the sound.

The Adire measures quite good for sure....

Maybe we should be listening to music instead of swept tones.....

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post #66 of 170 Old 01-27-09, 06:21 PM Thread Starter
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Re: MobilePre ECM8000 oddities

Bruce, to me that is music!
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post #67 of 170 Old 01-27-09, 06:56 PM
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Re: MobilePre ECM8000 oddities

Bruce & Anthony -

A big thanks for helping me troubleshoot, and for all of the effort you two have put into this series of experiements. I'm still waiting for my DBX mic and cal files to come back from Cross-Spectrum and I will post my results when I get those. In the meantime, I think I'll do another run with the ECM and split cal file.

Bruce, can I ask a favor? Would you please retest at 3 feet (horizontal mic) to see if that induces some roll-off in your Proacs? And would you also measure on the midrange axis as well? You're Proac's use a tweeter that is similar to mine and I want to see if distance affects the HF response and also what sort effect being off-axis has.

Thanks,

- Tim
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post #68 of 170 Old 01-27-09, 07:29 PM
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re: ECM8000 microphone measuring techniques and usage discussion

Robbo -

I have the DBX mic, and I just had it calibrated. I don't think that cal file listed in the link you provided is all that accurate. It only shows about a 1.5dB rise in the treble response of the mic, when it is really more like 5dB.

- Tim
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post #69 of 170 Old 01-27-09, 08:12 PM
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re: ECM8000 microphone measuring techniques and usage discussion

Hi Tim,

The close mic scan of my raven 3.2 is fairly flat from 1k to 25k. (As per it's measured graph that came with it)
I can repost just the 1k to 25k graph if you like.
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post #70 of 170 Old 01-27-09, 10:29 PM
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Re: MobilePre ECM8000 oddities

Looking a little deeper at your guys' graphs vs. mine, both of you are showing a difference of roughly 6dB at 20KHz in your horizontal vs. vertical mic positions. This difference coincides with the differences shown in the FR plot of the ECM mic. My measurements show a difference of 12dB at 20KHz. What's up with that?


Last edited by hifisponge; 07-19-09 at 03:25 AM.
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