Dayton OmniMic Precision Measurement System - Page 16 - AVS | Home Theater Discussions And Reviews
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Old 01-26-2011, 12:05 PM
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Quote:
Originally Posted by Gooddoc View Post

The vast majority of all my measurements only require repeatable accuracy, not absolute accuracy. I mostly make comparative measurements to evaluate relative changes. So absolute accuracy is not exceedingly important to me. It needs to be close for sure - I don't want to be 5 or 10 dB off - but what's a couple dB between friends?

That is the problem with most mics. Without a proper calibration file the mic could be -/+ 10dB. Ethan Winer did a great test once with many popular mics showing how inaccurate they are without individual calibrations. The RadioShack SPL meters are notoruous for being inaccurate.

You could be EQing something down -3dB when its not really a peak at all.

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Old 01-26-2011, 12:06 PM
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Quote:
Originally Posted by Warpdrv View Post

There is no reason one can't just take a screen shot, "snip" program in win vista or win 7 and post up a jpg here on the forum..

Unless Penn means something else...

I just wanted to see what is in the files this program will save.

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Old 01-26-2011, 12:09 PM
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Mr. Waslo

How about adding EQing/Biquad export features for MiniDSP?? That would be a cool addition.

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Old 01-26-2011, 06:02 PM
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Folks,

Remember I'm supposed to be lettlng PE/Dayton handle the support and questions about this, rather than fumble around on the net behind their backs.... but I'll take a shot at some recent related questions since I've already set my foot in about the new rev. But please get with PE on these if you need more, they can coordinate things.

Penn, t6902wf: Not likely it will ever output coefficients or programming for other companyies' EQ boxes. But it does output easily readable FRD files (just plain old ASCII text of lists of Hz and dBs) that maybe some clever DIY person can write some software to crunch on. Use good sense though, don't let it try to EQ out of resonse suckouts.

There's no straight way to get a cal file out of OmniMic, it isn't really intended for use other than with its own software. The EQing done internally is done at several levels. No EQ is automatically applied to the mic's audio stream as it would be seen by another audio program. Though at low frequencies (for instance with REW to do bass EQ in a room) things should be pretty flat and well behaved, the big variations are up in the kHz.

Screen graphics resolution higher? This is technical software, you know, not Photoshop

You don't need to take screen shots to make a file of a single plot, use the "snapshot" icon to save to a file (in bmp or even in wmf files if you want something infinitely scalable). Or to save as ASCII FRD data, plain old "Save" file. (You don't save to the OmniMic directory, normally, just save to whatever folder is handy on your hard disk or thumb drive).

Quote:


>Multple FRs? Overlaying capabilities, sumations (sum measurements, tweeter + woofer)? Group Delay, waterfalls, Phase issues? Distortion? EQing recommendations? Gating?

Yes on waterfalls (two kinds, done LIVE, I'm really surprised no one has commented on those here yet), phase, harmonic distortion (also live!), gating, RT60.
No on summing (for now), EQ recommendations beyond just the graphs, group delay (though you can add/subtract fixed delays).

Below 5Hz isn't very likely, sorry. That's getting down to where the capsules would be way hard to verify or calibrate. OM graphs go only down to 12Hz.

Math: currently functional (in new version that PE should have up in a few days): normalization (change in response from a reference), filtering (apply a response to a response), evaluation if a curve lies between two others. And the ability to offset individual curves that are being displayed from files.

Thanks for the attention! (and sorry, Karl, if I'm interfering)

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Old 01-26-2011, 06:21 PM
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Quote:
Originally Posted by penngray View Post

That is the problem with most mics. Without a proper calibration file the mic could be -/+ 10dB.

Are you saying you don't trust the OmniMic calibration file?

Bill, what is the accuracy of a measured response?

Noah
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Old 01-26-2011, 06:28 PM
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Quote:
Originally Posted by bwaslo View Post

Remember I'm supposed to be lettlng PE/Dayton handle the support and questions about this, rather than fumble around on the net behind their backs...

I agree operational questions should be directed to PE, but aren't they just going to turn around and ask you the technical/upgrade questions?

Quote:
Originally Posted by bwaslo View Post

Math:... filtering (apply a response to a response)...

Not sure what this means; applying a response to a measured response?

Where does the first one come from?

It would be great if various filter functions as EQ devices could be tried to get a desired target response.

Noah
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Old 01-27-2011, 06:36 AM
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Quote:
Originally Posted by noah katz View Post

Are you saying you don't trust the OmniMic calibration file?

Bill, what is the accuracy of a measured response?

Depends on how they create the calibration data for each mic.

To assume accuracy is simply a bad assumption that has been proven wrong with every mic ever created. Even the Dayton EMM-6 had some issues even though each mic is said to have a unique cal file is not a trust issue its simply a practical understanding of the products and the process.

You do realize that anyone with and accurate mic has either sent it off to be calibrated or has purchased a mic that came with unique calibration data.

Until 3rd parties confirm the Mic's accuracy its just not good business to assume anything. Its not a bad thing, its just standard stuff.

Not only the mic but the soundcard that is tied into the mic. We test our soundcards through loop back tests and there are issues with sound cards that need to be corrected in measurement software. This does all that? Its done for every product before its package? From my business POV, that is very, very costly to do so I still suspect generic cal data is used and the calibrated differences are minor but can still matter.

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Old 01-27-2011, 06:39 AM
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Quote:
Originally Posted by bwaslo View Post

Folks,

Remember I'm supposed to be lettlng PE/Dayton handle the support and questions about this, rather than fumble around on the net behind their backs.... but I'll take a shot at some recent related questions since I've already set my foot in about the new rev. But please get with PE on these if you need more, they can coordinate things.

Penn, t6902wf: Not likely it will ever output coefficients or programming for other companyies' EQ boxes. But it does output easily readable FRD files (just plain old ASCII text of lists of Hz and dBs) that maybe some clever DIY person can write some software to crunch on. Use good sense though, don't let it try to EQ out of resonse suckouts.

There's no straight way to get a cal file out of OmniMic, it isn't really intended for use other than with its own software. The EQing done internally is done at several levels. No EQ is automatically applied to the mic's audio stream as it would be seen by another audio program. Though at low frequencies (for instance with REW to do bass EQ in a room) things should be pretty flat and well behaved, the big variations are up in the kHz.

Screen graphics resolution higher? This is technical software, you know, not Photoshop

You don't need to take screen shots to make a file of a single plot, use the "snapshot" icon to save to a file (in bmp or even in wmf files if you want something infinitely scalable). Or to save as ASCII FRD data, plain old "Save" file. (You don't save to the OmniMic directory, normally, just save to whatever folder is handy on your hard disk or thumb drive).


Yes on waterfalls (two kinds, done LIVE, I'm really surprised no one has commented on those here yet), phase, harmonic distortion (also live!), gating, RT60.
No on summing (for now), EQ recommendations beyond just the graphs, group delay (though you can add/subtract fixed delays).

Below 5Hz isn't very likely, sorry. That's getting down to where the capsules would be way hard to verify or calibrate. OM graphs go only down to 12Hz.

Math: currently functional (in new version that PE should have up in a few days): normalization (change in response from a reference), filtering (apply a response to a response), evaluation if a curve lies between two others. And the ability to offset individual curves that are being displayed from files.

Thanks for the attention! (and sorry, Karl, if I'm interfering)

Thank you very much!!

Im also surprised none of the users have posted all those great plots that exist.

Maybe Dayton/PE should have a Rep checking in on this discussion?

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Old 01-27-2011, 08:12 AM - Thread Starter
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There is also a couple of threads over at the PE Forum, but from scanning through the threads - it seems to me that even on a Dedicated PE forum, they don't have much interest in responding to anyone over there either Bill....

Quote:


Remember I'm supposed to be lettlng PE/Dayton handle the support and questions about this, rather than fumble around on the net behind their backs.... but I'll take a shot at some recent related questions since I've already set my foot in about the new rev. But please get with PE on these if you need more, they can coordinate things.

One would think that fielding phone calls from every tom dick and harry on this product is not the most effective way of handling support in this day and age.... I highly doubt the sales people that field phone calls at PE are going to be able to answer some of the serious technical questions that go on with the forums...

Is it not possible for someone with the Technical background with this product to be able to help out on the forum at all ? I'm not suggesting that it be here - but why not even their own forum....?
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Old 01-27-2011, 10:24 AM
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Penn,

Were you able to do anything with those frd files?

James
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Old 01-27-2011, 04:07 PM
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Goodoc have you tried loading the frd file from the omnibus software into REW.

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Old 01-28-2011, 07:04 AM
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I am pretty sure a frequency response file can be generated in Omni mic that can be opened in REW but I would like to confirm it. My Mini DSP shipped and I want to have the omni mic in house before it gets here if I am going to get one.

Can someone e-mail me a omni mic .frd file so I can test it.
PM me for an email address.

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Old 01-28-2011, 07:11 AM
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Quote:
Originally Posted by exojam View Post

Penn,

Were you able to do anything with those frd files?

James

I have them in Email. Thanks!!

I was not home until yesterday and I have too many things going on today...Like Golf

Can anyone with the Omni package run some waterfall measurements and post the pics?

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Old 01-28-2011, 07:16 AM
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I am hoping to get some more measurements tonight so I will try to get some waterfalls. I need to measure again since I changed my room around. I also want to re-run Audessy and compare graphs with it on and off.

James
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Old 01-28-2011, 07:55 AM
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I was able to import the FRD file Exojam was nice enough to email me.

When I opened it REW asked this question.

Apply c-weighting compensation to the data?
If the data was measured with a c-weighted SPL meter and inverse C-weighting was not applied during the measurement, select yes to reverse the effect of the meters C-weighting curve.


Does anyone know the correct response to this question?

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Old 01-28-2011, 08:15 AM
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Quote:
Originally Posted by penngray View Post

I was not home until yesterday and I have too many things going on today...Like Golf

Playing golf, ouch that hurt. The closest I can come without hopping on a plane is putting in my office and hitting balls at a golf dome.

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Old 01-28-2011, 08:19 AM
 
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There are some up at the Parts Express pages
http://www.parts-express.com/pdf/OmniMic/index.htm


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Old 01-28-2011, 11:54 AM
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Well I pulled the trigger on the Omni mic, mic stand and extended USB cable. It should hit around the same time as my minidsp.

I find PE to be odd when it comes to shipping. Sometimes it comes the next day sometimes in several days we will see.

Beyond dialing in the minidsp I am going to do a Infinite baffle in the spring for a friend, should be fun.

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Old 01-28-2011, 12:03 PM
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I just ordered one too.

Noah
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Old 01-28-2011, 12:14 PM
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Quote:
Originally Posted by noah katz View Post

I just ordered one too.

It is Friday, I think a little splash of vodka in the cool-aid is in order.

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Old 01-28-2011, 12:42 PM
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Old 01-28-2011, 01:28 PM
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Originally Posted by t6902wf View Post

I find PE to be odd when it comes to shipping. Sometimes it comes the next day sometimes in several days we will see.

Mine left Cincinnati (464 miles to my house) on the 21st. It traveled FedEx to Haggerstown, MD (63 Miles to my house) arriving on the 24th. It was handed off the same day to the Smartpost facility in Martinsburg WV a 23 mile trip. Two days later the USPS picked it up for the last 55 miles to my house.

Anyone seen my unit?
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Old 01-28-2011, 01:38 PM
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Quote:
Originally Posted by BIGmouthinDC View Post

Mine left Cincinnati (464 miles to my house) on the 21st. It traveled FedEx to Haggerstown, MD (63 Miles to my house) arriving on the 24th. It was handed off the same day to the Smartpost facility in Martinsburg WV a 23 mile trip. Two days later the USPS picked it up for the last 55 miles to my house.

Anyone seen my unit?

Great....

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Old 01-28-2011, 01:42 PM
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I don't have the unit yet but I think using a CD for test tones has benefit. If there is a problem in your signal chain it will show up. I am most concerned with content played through my Bluray player in my theater. Running the signal through it makes sense to me.

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Old 01-28-2011, 02:33 PM
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Quote:
Originally Posted by BIGmouthinDC View Post

Mine left Cincinnati (464 miles to my house) on the 21st. It traveled FedEx to Haggerstown, MD (63 Miles to my house) arriving on the 24th. It was handed off the same day to the Smartpost facility in Martinsburg WV a 23 mile trip. Two days later the USPS picked it up for the last 55 miles to my house.

Anyone seen my unit?

Where does the tracking say it is now?

James
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Old 01-28-2011, 02:36 PM
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Quote:
Originally Posted by t6902wf View Post

Goodoc have you tried loading the frd file from the omnibus software into REW.

I'm on vacation . By the time I get back it seems this will all be figured out!
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Old 01-28-2011, 04:53 PM
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Quote:
Originally Posted by t6902wf View Post

When I opened it REW asked this question.

Apply c-weighting compensation to the data?
If the data was measured with a c-weighted SPL meter and inverse C-weighting was not applied during the measurement, select yes to reverse the effect of the meters C-weighting curve.

Does anyone know the correct response to this question?

The correct answer would be no.
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Old 01-28-2011, 05:51 PM
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Well I have some measurements.

I ran the Audyssey right before making these. I have made a few changes to the room so I wanted to run some more measurements to see what I have.

If someone can tell me how to get the waterfalls to go below 200HZ that would be great because I could not seem to get them to do so.

Each measurement was taken with Audyssey and off. The screen grabs will say “aud” when it was on and “no aud” when it was off.

I can see that Audyssey did bump the db level about 10db from about 12-25HZ.

I also ran the harmonic distortion piece. This was done at the same position as every other graph. I know the “help” file says it should be a closed mic measurement but I wanted to see what it showed at the listening position and there is a big difference between when Audyssey was on and off.

The thrid graph says "suns" but should say subs.

One last thing, if a graph says "all", that means L-C-R, surround L-R and subs were all in the measurement.

James
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Old 01-28-2011, 05:52 PM
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Old 01-28-2011, 05:54 PM
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