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Room measuring with ECM8000
Old 17th May 2012 | Show parent
  #31
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Jens Eklund's Avatar
 

Quote:
Originally Posted by Mctwins View Post
I can come and do some measurements for you, if you wan't. In one of your controlrooms that is.
You don´t even care to figure out what type of mic you’re using or how to use it properly, so why would anyone want to hire you?

I´m done talking to you, It´s just no use in trying. I guess you where serious about this:
GIK or Realtraps?
Old 17th May 2012 | Show parent
  #32
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Quote:
Originally Posted by onceagain View Post
Mctwins, are any of your measurements posted on here? I would like to view them if possible, out of interest.
Sorry, I missed this post.

Take a look here

My room
Old 17th May 2012 | Show parent
  #33
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Mctwins's Avatar
 

Quote:
Originally Posted by Jens Eklund View Post
You don´t even care to figure out what type of mic you’re using or how to use it properly, so why would anyone want to hire you?

I´m done talking to you, It´s just no use in trying. I guess you where serious about this:
GIK or Realtraps?
Sorry, I can't view this thread.
I'll do it for free for you if you are interested.
Old 17th May 2012 | Show parent
  #34
Gear Nut
 

Nice looking room, but only for listening?! Different strokes i guess

I'd like to see the response graph without the 1/3 octave smoothing.
Old 17th May 2012 | Show parent
  #35
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Quote:
Originally Posted by Mctwins View Post
Sorry, I can't view this thread.
I'll do it for free for you if you are interested.

What part of:
Quote:
Originally Posted by Jens Eklund View Post
I´m done talking to you
did you not understand?
Old 17th May 2012 | Show parent
  #36
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Quote:
Originally Posted by onceagain View Post
I'd like to see the response graph without the 1/3 octave smoothing.
https://www.gearslutz.com/board/7887830-post32.html

Old 17th May 2012 | Show parent
  #37
Gear Guru
Answer the OP

Aaron, I'm afraid the quality of the answer is directly related to it's length.

I fully concur with Jens summary https://www.gearslutz.com/board/7268743-post93.html

Some nuances.

FR and other response vary radically over fairly small distances.
To get a sense of what is happening with the sweet spot you need several measurements.
Dirac Live uses 9, Rod has mentioned using 40 or so.
To shake the old nose habit I suggest starting with a least two positions.
Where the ears will be.
If you want to detect the speaker response primarily, point a Direct Field Mic at the tweeter or acoustic middle of the speaker.
Mic half a head to the left, pointing directly at Left speaker, similar for Right.
You can use the software to combine L+R measures or you can do it organically...
While the Mic is in each spot, it is easy to hit that Mono switch, drive both speakers to get a real L+R reading.
View these Left (L+R) and Right (L+R) 20-300H only. They will have horrible comb filtering at HF, which the ear does not.


If you are trying to identify reflections, I would point the mic in the direction of interest.

The Diffuse Field mics are not common. Mics in US standard SLM's are Diffuse Field, but we have found serious problems trying to use them for measurement.
The advice to point the mic upwards is fairly irrelevant (unless you want to ignore the HF from both speakers equally and focus on ceiling reflections)

Many of the guides still suggest it. That and driving two speakers.
It leads to perpetual motion confusion.

More simply put. With a normal Direct Field Mic, point it at what you want to hear. DOH!

DD
Old 17th May 2012 | Show parent
  #38
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Quote:
Originally Posted by Jens Eklund View Post
Still, where is your measurements?
Old 17th May 2012 | Show parent
  #39
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Rod Gervais's Avatar
 

Quote:
Originally Posted by Mctwins View Post
The EMC8000 mic is allready calibrated, JUST MEASURE, for crying out loud.
A statement like that does not help your cause here......

Microphones are not "calibrated" by the manufacturer, they are manufactured and then tested to determine what anomalies exist - the person who purchases the mic is then provided with a "calibration" (data) file they can input into the software they are using in order to correct for the inaccuracies of the microphone in question.

Quite often a mic can be purchased without the file - if the buyer is willing to pay a little more the mic is then measured and the sale includes the calibration file.

Not only is an EMC8000 not "calibrated", calibration files for that mic do not appear to available from the manufacturer. I have checked their website as well as sources to purchase the mic from - and do not see any reference to calibration files.

This is (of course) not surprising with a $50 microphone....

You can not make a claim as to how flat it is or is not - you have no way of knowing anything other than the claims by the manufacturer. There are those who claim the mics are flat and those who claim they are no where near flat ....... although those who claim they are not flat are probably more knowledgeable than those who claim they are.

This is a quote from a Musician's Friend review from someone who purchased one of these mics:

Quote:
They're noisy enough to be useless for anything other than high SPL frequency response measurements. That is if the specs they published online weren't different than what's in the documentation. The online docs show a ruler flat response from 1KHz down to 20Hz. In actuality, they're flat only down to about 200Hz and the response drops like a rock below that. They also show only a +2dB rise above 2KHz but in actuality, it's closer to +6dB. This makes the mics worthless even for measurement purposes. Behringer lied like a dog on this one. I didn't expect anything great, but these are a total waste of money.
This is not to say that they are not reasonably adequate for home use - although certainly not for pro use.

Rod
Old 17th May 2012 | Show parent
  #40
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Quote:
Originally Posted by Mctwins View Post
Still, where is your measurements?
https://www.gearslutz.com/board/7888037-post35.html

GIK or Realtraps?
Old 17th May 2012 | Show parent
  #41
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Mctwins's Avatar
 

Quote:
Originally Posted by Jens Eklund View Post
i don't understand why you are showing my measurements all the time, just show your own measurements from your own room.
Old 17th May 2012 | Show parent
  #42
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Quote:
Originally Posted by onceagain View Post
Nice looking room, but only for listening?! Different strokes i guess

I'd like to see the response graph without the 1/3 octave smoothing.
Look at the thread GIK and Realtrap, there is unsmoothed.
Old 17th May 2012 | Show parent
  #43
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Jens Eklund's Avatar
 

Quote:
Originally Posted by Mctwins View Post
i don't understand why you are showing my measurements all the time, just show your own measurements from your own room.
https://www.gearslutz.com/board/7888037-post35.html
Old 17th May 2012 | Show parent
  #44
Gear Guru
SuperCALifragilistic

Calibration is not mandatory, nor even necessary, nor even useful, for the vast majority of measurement work.
Mic variations of single figure dB's are tiny compared to room variations which can be double digit.
Even more so the Sound Card Cal. Single decimal variations.

I encourage anyone writing manuals or primers on measurement to shift Cal to the Power User section at the end. You don't need Cal until you know what it is.

Unless we want to keep newbies eternally confounded?

DD
Old 17th May 2012 | Show parent
  #45
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Rod Gervais's Avatar
 

Quote:
Originally Posted by Mctwins View Post
Look at the thread GIK and Realtrap, there is unsmoothed.
The more you apply smoothing the less anomalies you see in the results......

In other words - less smoothing presents a greater amount of detail.

You have greater detail with 1/10th smoothing than you do with 1/3 smoothing - and the greatest detail with no smoothing..........

Why not post your test results with no smoothing so we can see what it looks like in that form?

Rod
Old 17th May 2012 | Show parent
  #46
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Rod Gervais's Avatar
 

Quote:
Originally Posted by DanDan View Post
Calibration is not mandatory, nor even necessary, nor even useful, for the vast majority of measurement work.
Mic variations of single figure dB's are tiny compared to room variations which can be double digit.
Even more so the Sound Card Cal. Single decimal variations.

I encourage anyone writing manuals or primers on measurement to shift Cal to the Power User section at the end. You don't need Cal until you know what it is.

Unless we want to keep newbies eternally confounded?

DD
Dan,

I was not presenting a position either pro or con regarding mic calibration - I was simply replying to the post made by Mctwins where he stated:

Quote:
The EMC8000 mic is allready calibrated
That is certainly not the case - and it clearly indicates a lack of understanding on his part.

Rod
Old 17th May 2012 | Show parent
  #47
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Jens Eklund's Avatar
 

Quote:
Originally Posted by DanDan View Post
Calibration is not mandatory, nor even necessary, nor even useful, for the vast majority of measurement work.
Mic variations of single figure dB's are tiny compared to room variations which can be double digit.
Even more so the Sound Card Cal. Single decimal variations.

I encourage anyone writing manuals or primers on measurement to shift Cal to the Power User section at the end. You don't need Cal until you know what it is.

Unless we want to keep newbies eternally confounded?

DD

Then you also need to tell beginners to simply ignore the frequency range above about 3-8 kHz (depending on the size of capsule) if the user does not fully understand the different types of mics/calibrations and how to use them.

This is probably the easiest way of keeping acoustic measurements easy for beginners. How often do you have a FR related problem above 3-8 kHz anyway …
Old 17th May 2012 | Show parent
  #48
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Quote:
Originally Posted by Rod Gervais View Post
Dan,

I was not presenting a position either pro or con regarding mic calibration - I was simply replying to the post made by Mctwins where he stated:



That is certainly not the case - and it clearly indicates a lack of understanding on his part.

Rod
I don´t use the EMC8000, but I thought maybe the package contained some cal files (or downloadable from Behringer) in order to be able to use it in both free field and diffuse field (and no, I did not think that every single EMC mic came with a unique cal file, not at this price point)?

If not, what kind of field does it measure "flat" in, do you know?
Old 17th May 2012 | Show parent
  #49
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Mctwins's Avatar
 

Quote:
Originally Posted by Rod Gervais View Post
The more you apply smoothing the less anomalies you see in the results......

In other words - less smoothing presents a greater amount of detail.

You have greater detail with 1/10th smoothing than you do with 1/3 smoothing - and the greatest detail with no smoothing..........

Why not post your test results with no smoothing so we can see what it looks like in that form?

Rod
According to ARTA, the last graph of those three I posted, is DFT unsmoothed.
If you don't belive me, it's time for you guys to contact the founder of ARTA, Ivo Mateljan.

You guys are the experts here.
Old 17th May 2012 | Show parent
  #50
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Mctwins's Avatar
 

Quote:
Originally Posted by Rod Gervais View Post
Dan,

I was not presenting a position either pro or con regarding mic calibration - I was simply replying to the post made by Mctwins where he stated:



That is certainly not the case - and it clearly indicates a lack of understanding on his part.

Rod
I have two mics, EMC8000 and dbxRTA-M, the measurements results is the same in my room for both the mics.
Old 17th May 2012 | Show parent
  #51
Gear Guru
Review

I hadn't noticed that review Rod.
Hmmm.
Here's a Behringer measured by Cross Spectrum Labs.
http://www.cross-spectrum.com/cslmic...mic_report.pdf

It's OK but hardly flat. Given Behringers dubious manufacturing standards, correct that, not dubious, distinctly bad, it would seem wise to
buy a mic with a Calibration chart. In which case one would probably buy the Cross Spectrum product rather than the Behringer.

Furthermore the response looks quite Diffuse Field to me LOL!

DD
Old 17th May 2012 | Show parent
  #52
Gear Nut
 

Excuse my ignorance on this, but do those results mean that the mic is best used pointing to the ceiling, 90 degrees from the speakers?
Old 17th May 2012 | Show parent
  #53
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Jens Eklund's Avatar
 

Quote:
Originally Posted by onceagain View Post
Excuse my ignorance on this, but do those results mean that the mic is best used pointing to the ceiling, 90 degrees from the speakers?
Yes, and ignore the response above about 10 kHz.
Old 17th May 2012 | Show parent
  #54
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Jens Eklund's Avatar
 

Quote:
Originally Posted by DanDan View Post
The Diffuse Field mics are not common.
If the Behringer is a diffuse field type, the above is far from true ...
Old 17th May 2012 | Show parent
  #55
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Glenn Kuras's Avatar
Quote:
Originally Posted by Jens Eklund View Post
Yes, and ignore the response above about 10 kHz.
I know this question comes up a lot so I will put it down for my next test in our test room. I use a Earth Works SRO2 microphone.
Old 17th May 2012 | Show parent
  #56
Gear Guru
Mess

We are dealing with bottom of the barrel product here.
The Behringer and it's cousins, cannot be trusted to be flat or to have a response that could be called Diffuse or Direct. Plus the noise level and headroom are bad.
Even at a higher quality level, the fog of confusion persists. A Neutrik mic used in a survey was called Free Field (Direct) by the maker, but had a rising response.
In the tests they pointed it upwards!

The common issue with all of these seems to be rising HF.
Pragmatically again I concur with Jens. Ignore the HF but note it is +3dB at 10K so ignore anything over 4K?

But if we are trying to generate Target/Reference curves for DRC or whatever, there is a problem.
As ever, I recommend buying a mic with a trustworthy frequency response.
Earthworks, DPA, both useful for recording work. Really useful.
For measurement only a mic with a Cal file, e.g. Dayton.
Or build one using the Panasonic capsule which seems to be remarkably flat. If you believe Panasonic...
DD
Old 17th May 2012 | Show parent
  #57
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Rod Gervais's Avatar
 

Quote:
Originally Posted by Mctwins View Post
I have two mics, EMC8000 and dbxRTA-M, the measurements results is the same in my room for both the mics.
Interesting that 2 cheap microphones, manufactured by different companies, would have exactly the same deficiencies.......

That doesn't even happen with any 2 mics manufactured in the same lot by the same company.............

Strange things do indeed happen with you twins.......

Rod
Old 17th May 2012 | Show parent
  #58
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by Rod Gervais View Post
Interesting that 2 cheap microphones, manufactured by different companies, would have exactly the same deficiencies.......

That doesn't even happen with any 2 mics manufactured in the same lot by the same company.............

Strange things do indeed happen with you twins.......

Rod
Maybe photoshop helps?
Old 17th May 2012
  #59
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Rod Gervais's Avatar
 

Hell - it is very difficult to even set up the same mic on 2 different tests and place it so precisely that you can get the same results on 2 separate occasions - I am starting to believe that McTwins must have super powers to pull things like this off.......

Perhaps he is really Batman or Superman in disguise...........

Rod
Old 17th May 2012 | Show parent
  #60
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Quote:
Originally Posted by Rod Gervais View Post
Hell - it is very difficult to even set up the same mic on 2 different tests and place it so precisely that you can get the same results on 2 separate occasions - I am starting to believe that McTwins must have super powers to pull things like this off.......

Perhaps he is really Batman or Superman in disguise...........

Rod
Rod, don't get so anal about it. If Behringer says ruler flat from 15-20K then I trust them. One can always debate if this is right or wrong. Not everybody can buy a expensive mic, but this mic is a god starting point. People don't even have the money to buy treatments and still want's a perfect room acoustics.

I have super powers in how to take care of the low end problems of a room.

I see that many don't have this super powers
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