Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 297 - AVS Forum
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post #8881 of 12288 Old 02-21-2014, 12:11 PM
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Originally Posted by 3ll3d00d View Post

For sub + mains integration work it doesn't really matter as the differences occur at high frequencies.

Not to mention that if you have a 0 cal file, measure, then measure at 90, compare. You can make your own correction curve.
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post #8882 of 12288 Old 02-21-2014, 12:30 PM
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Originally Posted by 3ll3d00d View Post

For sub + mains integration work it doesn't really matter as the differences occur at high frequencies.

That's good, so my efforts today weren't entirely in vain (sounds good anyway and all I changed after Audyssey was to raise the crossovers anyway, so nothing irreversible).

I've just moved my noisy Beringer NU6000DSP sub amp outside of the room into an understairs cupboard, so no more fan noise in quiet scenes, so I'm ready for a weekend of films now, with everything running spot on. cool.gif

Zooming: Been there, done that, bought the lens...
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post #8883 of 12288 Old 02-21-2014, 01:19 PM
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Originally Posted by jim19611961 View Post

Not to mention that if you have a 0 cal file, measure, then measure at 90, compare. You can make your own correction curve.

No, because in a room sound is arriving from multiple directions and not just one.

Markus

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post #8884 of 12288 Old 02-21-2014, 01:21 PM
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Originally Posted by toofast68 View Post

Funny you asked that...I have an email into them...waiting response...just hoping there was a "faster answer".

http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/4920_20#post_23808303

Well, looks like I was off about 10 pages! biggrin.gif

Do you remember if those measurements were L+R+Subs? I'm guessing they were since that was our convention for full range sweeps back then. I wonder how much of the HF roll off can be attributed to interference vs the cal file for the USB mics (since we know what the EMM-6 looks like from what Markus posted)?
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post #8885 of 12288 Old 02-21-2014, 01:25 PM
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Originally Posted by markus767 View Post

No, because in a room sound is arriving from multiple directions and not just one.

How many directions do you think the sound is coming from when the cal files are done?

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post #8886 of 12288 Old 02-21-2014, 01:27 PM
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Depends which angle should be calibrated. Common angles are 0°, 45° and 90°.

Markus

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post #8887 of 12288 Old 02-21-2014, 01:36 PM
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Originally Posted by markus767 View Post

^
Either from 0° or 90°.

If your close enough to the source (but not too close), the room reflections will be insignificant. The correction curve will not be absolutely precise, but ballpark is enough for most things.

Taking your curves for instance, knowing to add 1db at 5K, 2db at 10K, and 6db at 15k would be enough in most cases.




Just knowing those three data points gets you pretty close.

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post #8888 of 12288 Old 02-21-2014, 01:41 PM
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Originally Posted by jim19611961 View Post

If your close enough to the source (but not too close), the room reflections will be insignificant. The correction curve will not be absolutely precise, but ballpark is enough for most things.

Taking your curves for instance, knowing to add 1db at 4K, 2db at 10K, and 6db at 15k would be enough in most cases.

Did you try it? I'd think you'll run into problems.

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post #8889 of 12288 Old 02-21-2014, 01:42 PM
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Originally Posted by markus767 View Post

Did you try it? I'd think you'll run into problems.

See Edit

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post #8890 of 12288 Old 02-21-2014, 01:45 PM
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In the near field you'll get all sorts of weird effects at high frequencies. You'll probably get better results in the far field.

Markus

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post #8891 of 12288 Old 02-21-2014, 01:47 PM
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I can't believe I am reading that it's OK to wing the 90° calibration from folks that are sticklers for accuracy when doing measurements. {pinches self}
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post #8892 of 12288 Old 02-21-2014, 01:47 PM
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Quote:
Originally Posted by markus767 View Post

^
In the near field you'll get all sorts of weird effects at high frequencies. You'll probably get better results in the far field.

In either case, if you have a mic that only has one cal file, making a simple 3 or 4 data point correction to it gets you much closer.

edit: Perhaps looking at both would be useful. Maybe an average of several?

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post #8893 of 12288 Old 02-21-2014, 01:48 PM
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Originally Posted by pepar View Post

I can't believe I am reading that it's OK to wing the 90° calibration from folks that are sticklers for accuracy when doing measurements. {pinches self}

To the contrary. I am saying making a correction curve that is a little bit off is better than turning around a mic and being way off. And below 1K or so, it doesnt seem to matter. So the new curve only needs adjustment above that point.

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post #8894 of 12288 Old 02-21-2014, 02:28 PM
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Originally Posted by jim19611961 View Post

To the contrary. I am saying making a correction curve that is a little bit off is better than turning around a mic and being way off. And below 1K or so, it doesnt seem to matter. So the new curve only needs adjustment above that point.

Got it. But just to be clear, Plan A should be to have (and use) 0° and 90° calibrations, right? smile.gif
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post #8895 of 12288 Old 02-21-2014, 02:28 PM
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Originally Posted by pepar View Post

Got it. But just to be clear, Plan A should be to have 0° and 90° calibrations, right?

Of course. But if you only have one...

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post #8896 of 12288 Old 02-21-2014, 02:30 PM
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Originally Posted by jim19611961 View Post

Of course. But if you only have one...

If not, then your Plan B will suffice ...
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post #8897 of 12288 Old 02-21-2014, 02:30 PM
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Originally Posted by jim19611961 View Post

Of course. But if you only have one...

...then point the f... mic in the direction the calibration file is made for.

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post #8898 of 12288 Old 02-21-2014, 02:34 PM
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Originally Posted by markus767 View Post

...then point the f... mic in the direction the calibration file is made for.

Which is obviously fine for measuring a speaker response for instance. Agreed. But when looking at sliced ETC's (for instance) whereby high frequency content can occur from any direction, a 0 cal mic turned to 90 with a curve may show things better.

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post #8899 of 12288 Old 02-21-2014, 02:50 PM
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Originally Posted by jim19611961 View Post

Which is obviously fine for measuring a speaker response for instance. Agreed. But when looking at sliced ETC's (for instance) whereby high frequency content can occur from any direction, a 0 cal mic turned to 90 with a curve may show things better.

Maybe, maybe not. Who knows?
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post #8900 of 12288 Old 02-21-2014, 02:57 PM
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Originally Posted by markus767 View Post

Maybe, maybe not. Who knows?

Just did an experiment. I took my 0 cal mic and put it about 18" in front of the tweeter. I turned off the opposit channel. I ran a 10K warble tone with the mic pointed 0 degrees. Then at 90 degrees (making sure the point was still directly in front of the tweeter at the same distance), and at 180 degrees.



(3db for each horizontal division)

Green = 0 degrees
Red = 90 degrees
Orange = 180 degrees

Its seems the reading drops 3db at 90 and almost 6db at 180. With a 90 mic, this would not be the case. And I would put forward that a 0 mic placed at 90 with a curve would do better than this.

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post #8901 of 12288 Old 02-21-2014, 06:13 PM
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Originally Posted by toofast68 View Post

Wow so confusing confused.gif

I have the UMM mic from Parts Express, how do I know if the calibration is for what direction....do I point ceiling or toward the front wall ?

This is what my file looks like:

"Sens Factor =-18.294dB, SERNO: 1381227"
 

If there is only one file it is most likely for 0 degrees, I.E.horizontal and pointing at the speaker. If you can, try returning it, and buy a calibrated one with 0, 45 and 90 degree files.

Don't forget to load the file before you start the measurement process.
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post #8902 of 12288 Old 02-21-2014, 06:55 PM
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Originally Posted by Digione View Post


If there is only one file it is most likely for 0 degrees, I.E.horizontal and pointing at the speaker. If you can, try returning it, and buy a calibrated one with 0, 45 and 90 degree files.

Don't forget to load the file before you start the measurement process.


Yep, since found out I goofed...I thought I ordered from cross spectrum, but I clicked on the wrong link from their site and ended up buying from Parts Express - I tried to return and they told me to pound salt.  Lost a customer for life they did as well as everyone else that I talk to...too bad companies no longer do the right thing.

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post #8903 of 12288 Old 02-22-2014, 01:59 AM
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Originally Posted by jim19611961 View Post

Just did an experiment.

Yes, omni mice aren't omni at higher frequencies. That's what one has to keep in mind regardless of calibration files.

Markus

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post #8904 of 12288 Old 02-22-2014, 06:02 AM
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Quote:
Originally Posted by toofast68 View Post

Quote:
Originally Posted by Digione View Post

If there is only one file it is most likely for 0 degrees, I.E.horizontal and pointing at the speaker. If you can, try returning it, and buy a calibrated one with 0, 45 and 90 degree files.


Don't forget to load the file before you start the measurement process.


Yep, since found out I goofed...I thought I ordered from cross spectrum, but I clicked on the wrong link from their site and ended up buying from Parts Express - I tried to return and they told me to pound salt.  Lost a customer for life they did as well as everyone else that I talk to...too bad companies no longer do the right thing.


Parts Express did nothing wrong. It was 100% your error. You are out shipping both ways no matter what.

To do the "right thing", you need to send your microphone to cross spectrum for calibration. Lot's of people have sent their own microphones to Cross Spectrum to be calibrated. That is a simple low cost solution to correct your error!
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Originally Posted by J_Palmer_Cass View Post


Parts Express did nothing wrong. It was 100% your error. You are out shipping both ways no matter what.

To do the "right thing", you need to send your microphone to cross spectrum for calibration. Lot's of people have sent their own microphones to Cross Spectrum to be calibrated. That is a simple low cost solution to correct your error!


yeah, I agree it was my error...I was "just" outside the standard return window and if Parts Express was my company I would have did the right thing.  but nevertheless it was my fault.

 

I have an email into cross sprectrum - hopefully they will respond soon and yes I fully expect to pay for their services.

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post #8906 of 12288 Old 02-22-2014, 07:40 AM
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Originally Posted by markus767 View Post

Yes, omni mice aren't omni at higher frequencies. That's what one has to keep in mind regardless of calibration files.

They are omnidirectional on the horizontal plane when oriented at 90 degrees are they not?

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post #8907 of 12288 Old 02-22-2014, 07:51 AM
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No, omni means all directions not just the horizontal plane. Our omni mics aren't perfectly omni hence the potential problems arising from that fact can be somewhat alleviate by mic orientation.

Markus

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post #8908 of 12288 Old 02-22-2014, 08:07 AM
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Originally Posted by markus767 View Post

^
No, omni means all directions not just the horizontal plane. Our omni mics aren't perfectly omni hence the potential problems arising from that fact can be somewhat alleviate by mic orientation.

I know what omnidirectional means. The point is, you will get an even response on the horizontal plane when the mic is oriented at 90 degrees. Yes, in such a orientation, ceiling and floor reflections (for instance) will now NOT be on the horizontal plane.

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post #8909 of 12288 Old 02-22-2014, 09:44 AM
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Quick question regarding the UMM-6 mic. I have the onstage mic stand and adapter for the Audyssey mic, but that one is too small for the UNM-6. Can anyone recommend an adapter they are using? I'd like to use the mic stand from the start rather than the little tripod that comes with the mic. Once I get thus figured out I am ready to start down this rabbit hole. Thanks!

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post #8910 of 12288 Old 02-22-2014, 01:54 PM
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Quote:
Originally Posted by J_Palmer_Cass View Post

Parts Express did nothing wrong. It was 100% your error. You are out shipping both ways no matter what.

To do the "right thing", you need to send your microphone to cross spectrum for calibration. Lot's of people have sent their own microphones to Cross Spectrum to be calibrated. That is a simple low cost solution to correct your error!

Well, I wouldn't be so hard on him. IMO, it is boneheaded for Cross Spectrum to link to a competitor's website, especially when they could link to the mic's page on the MANUFACTURER'S web site. I would go so far as to email Herb and ask him if he would give him a "deal" on calibrating the mic. I probably would leave out the word "boneheaded" though. smile.gif

Jeff
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