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A better solution is to use a laptop.
I have a laptop (actually its my wife's) but its so much easier and faster to just use my HTPC... plus the HDMI is already connected to my AVR. The 10-footer is all I need to reach the furthest listening positions. I purchased this 15-footer with repeater for an entirely different purpose (to extend a USB lan card for better reception) but as long as I have it here why not compare the two and see if it would be a workable solution for others?
 

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I have a laptop (actually its my wife's) but its so much easier and faster to just use my HTPC... plus the HDMI is already connected to my AVR. The 10-footer is all I need to reach the furthest listening positions. I purchased this 15-footer with repeater for an entirely different purpose (to extend a USB lan card for better reception) but as long as I have it here why not compare the two and see if it would be a workable solution for others?
No reason not to and by all means, show us some results.
 

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UMIK-1 and CM-140 side-by-side

I wonder if some of you more seasoned hands might chime in to comment... I'm a brand-new user to REW, with a brand-new UCA202 (dangling off an older XP SP3 laptop), a brand-new UMIK-1 (700-0410), and a brand-new CM-140 ('verified' model bought from Cross-Spectrum Labs).

Reading through various posts, and seeing some users expressing reservations about the UMIK-1 I was curious to see what results would come from running the same sweep through the same speaker at the same settings through the two mics... in this case, run sweeps with the UMIK-1 then with the CM-140 while touching nothing other than the connection to the laptop.

The two mics were placed one atop the other on a tripod about two meters away from the loudspeaker... a nothing-special old bookshelf chosen strictly for convenience (it was sitting there on the bench). Tip-to-tip, the mics were perhaps an inch apart. The CM-140 was connected via the UCA202 inputs, while the UMIK-1 was connected directly to the laptop via USB. The "off test" mic was physically disconnected in all cases. The 700-0410 cal file was used, then cleared before running the CM-140.

Two sweeps with the UMIK-1 (with cal file) then one CM-140, as above, from 58Hz to 14kHz with -nothing- altered other than the mic being used:


Other than the obvious liabilities of the speaker under test, am I comparing these two mics appropriately? The CM-140 shows as the green trace, difference is most noticeable (appx 3dB) at ~8kHz.

FWIW it was interesting to note that with the miniDSP cal file cleared, a sweep with the UMIK-1 is practically indistinguishable from the CM-140:


Just to repeat, there was absolutely nothing "optimized" nor "lab conditions" of any sort employed... on the contrary, this particular room has a lousy noise floor (multiple desktops and a switch running, all with fans) so the CM-140 is reading 64.something C scale 'slow' just sitting there on the tripod.

In the eyes of an REW/audio-testing newb, there appears to be fair correlation between the UMIK-1 and the CM-140 under the circumstances... enough, any way to recall the old Chinese proverb that "man with two clocks never know what time it is".

Does this answer anyone's concerns, or simply raise more questions? ...as noted at the outset, I've got about a half-hour total experience with all of the above so pls don't shoot the messenger :blink:

BTW "thanks!" to both miniDSP and Cross-Spectrum Labs for great service... the UMIK-1 was ordered on Saturday, 2/16 and delivered Thursday 2/21; the CM-140 order was placed on Monday, 2/25 and arrived here Thursday 2/28.

Ed

edit: - oddly, I can see two images above during "preview" but not once saved... will get to the bottom of it.

For those interested, the first photo is http://ironcreek.net/~ed/justcrap/mic comparo.jpg and the second http://ironcreek.net/~ed/justcrap/mic comparo2.jpg

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Welcome to the shack ejh2854!

Thanks for the info which will surely be of help to the more experienced. Hm, so both mics are either correct or both incorrect without using the UMIK-1 cal file. My UMIK-1 has not arrived just yet. I ordered mine on Monday 2/18. I think it's hit or miss on shipping time.
 

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Re: UMIK-1 and CM-140 side-by-side

I wonder if some of you more seasoned hands might chime in to comment... I'm a brand-new user to REW, with a brand-new UCA202 (dangling off an older XP SP3 laptop), a brand-new UMIK-1 (700-0410), and a brand-new CM-140 ('verified' model bought from Cross-Spectrum Labs).

Reading through various posts, and seeing some users expressing reservations about the UMIK-1 I was curious to see what results would come from running the same sweep through the same speaker at the same settings through the two mics... in this case, run sweeps with the UMIK-1 then with the CM-140 while touching nothing other than the connection to the laptop.

The two mics were placed one atop the other on a tripod about two meters away from the loudspeaker... a nothing-special old bookshelf chosen strictly for convenience (it was sitting there on the bench). Tip-to-tip, the mics were perhaps an inch apart. The CM-140 was connected via the UCA202 inputs, while the UMIK-1 was connected directly to the laptop via USB. The "off test" mic was physically disconnected in all cases. The 700-0410 cal file was used, then cleared before running the CM-140.

Two sweeps with the UMIK-1 (with cal file) then one CM-140, as above, from 58Hz to 14kHz with -nothing- altered other than the mic being used:


Other than the obvious liabilities of the speaker under test, am I comparing these two mics appropriately? The CM-140 shows as the green trace, difference is most noticeable (appx 3dB) at ~8kHz.

FWIW it was interesting to note that with the miniDSP cal file cleared, a sweep with the UMIK-1 is practically indistinguishable from the CM-140:


Just to repeat, there was absolutely nothing "optimized" nor "lab conditions" of any sort employed... on the contrary, this particular room has a lousy noise floor (multiple desktops and a switch running, all with fans) so the CM-140 is reading 64.something C scale 'slow' just sitting there on the tripod.

In the eyes of an REW/audio-testing newb, there appears to be fair correlation between the UMIK-1 and the CM-140 under the circumstances... enough, any way to recall the old Chinese proverb that "man with two clocks never know what time it is".

Does this answer anyone's concerns, or simply raise more questions? ...as noted at the outset, I've got about a half-hour total experience with all of the above so pls don't shoot the messenger :blink:

BTW "thanks!" to both miniDSP and Cross-Spectrum Labs for great service... the UMIK-1 was ordered on Saturday, 2/16 and delivered Thursday 2/21; the CM-140 order was placed on Monday, 2/25 and arrived here Thursday 2/28.

Ed

edit: - oddly, I can see two images above during "preview" but not once saved... will get to the bottom of it.

For those interested, the first photo is http://ironcreek.net/~ed/justcrap/mic comparo.jpg and the second http://ironcreek.net/~ed/justcrap/mic comparo2.jpg

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Thanks for posting that. What about below 58hz?
 

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No reason not to and by all means, show us some results.
Okay so here it is... I actually re-ran this comparison 5 times to be sure the results were repeatable. I used my UMIK in a mic holder at the end of an rigid boom on a mic stand with the 4 foot USB that comes with the UMIK attached to first a 10-foot USB extension cable (no repeater), save the measurement then I close REW swap with the 15-foot USB extension with repeater while moving nothing else and using the same USB port, open REW, measured and saved, then compared the two. Below is a capture of a typical comparison where MAGENTA is with the 10-foot extension without repeater and the TEAL is the 15-footer with repeater. As you can see the traces are nearly identical... So there is a very tiny and barely measureable difference (probably due to the added delay of the repeater and added 5-foot length possibly) but that difference is never going to be audibly noticable. So, anyone contemplating the use of a long USB extension with repeater (AKA booster circuit) draw your own conclusions...
 

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Apparently all the online calibration files for the first batch of UMIKs has now been replaced with the same format as used for the second batch... also now ending before 20Hz.
 

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Problem solved!
Easy way.
It sounds more like a step backwards to me - especially as many of us wanted the extension to 15Hz and the ~5Hz cal file looked even better. I'd not have bought if it had only been to 20Hz at the time.

So does this mean the original files (I'm in that batch) are "not right"/can't be trusted? :dontknow:
 

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It sounds more like a step backwards to me...
Sure it its.
I was just being sarcastic. :)

Well:

1- Or the hardware isn't capable of being calibrated below 20Hz and so the first batch had a "non realistic" calibration data in that range;

2- Or the hardware is capable of being calibrated below 20Hz and someone "forgot" to calibrate the second batch below that frequency.

Looking at the specs in the UMIK-1 webpage it shows:
"Frequency response 20Hz-20kHz +/-0.5dB with calibration file loaded"

On the box of my UMIK-1 says:
"Frequency response 18Hz ~ 20kHz"

So maybe the most probably option is number 1 I guess.
 

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...Or the hardware isn't capable of being calibrated below 20Hz and so the first batch had a "non realistic" calibration data in that range...
I'm pretty sure it CAN be calibrated below 20Hz, the only real question is one of tolerance. I will assume the tolerance opens up as the cal freqs go lower... leading to less reliable values being generated. Personally I don't care if the tolerance in those lower freqs are +/- 2dBs, its still gotta be better than nothing. Looking at the composite graph that was created on the first batch... it goes crazy below 20Hz meaning I sure would never be able to guess what happens to my UMIKs response down there, so I'd rather have some 'ballpark' numbers than a flat 0dBs (no correction). I DON'T NEED that tight +/- .5dBs really, just get me in the ballpark down there and I'd be good with that.
 

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It sounds more like a step backwards to me - especially as many of us wanted the extension to 15Hz and the ~5Hz cal file looked even better. I'd not have bought if it had only been to 20Hz at the time.

So does this mean the original files (I'm in that batch) are "not right"/can't be trusted? :dontknow:
Haven't they changed calibration companies, and that's the reason?
 

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Haven't they changed calibration companies, and that's the reason?
My understanding is they only changed something to do with the test bed to supposedly make it more accurate... the explanation was vague. Then they said they were changing the calibration file format of the first batch to match with the second batch as apparently that can be generated from the raw data, however specifics are lacking. Perhaps some one should ask over on the manufacturer's forum for a more detailed response?
 

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My understanding is they only changed something to do with the test bed to supposedly make it more accurate... the explanation was vague. Then they said they were changing the calibration file format of the first batch to match with the second batch as apparently that can be generated from the raw data, however specifics are lacking. Perhaps some one should ask over on the manufacturer's forum for a more detailed response?

Matter of opinion, personally are you happy with the UMIK?

What held you back from buying the UMM-6?

Bit of confusion which one to buy on this site.
 

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Matter of opinion, personally are you happy with the UMIK?

What held you back from buying the UMM-6?

Bit of confusion which one to buy on this site.
Yeah, now that its gotten past the bogus calibration file and crazy sensitivity factor thing, it does seem like a good quality mic... its just that I wish they would still publish the below 20Hz stuff in the calibration files, even if they now think the data to be unreliable... I mean how bad can it be really? Its still got to be better than not knowing anything and having to go with no calibration values at all at those really low freqs.

To tell you the truth, I didn't really look very hard at the UMM-6 through Cross-Spectrum because I ASSUMED (my fault) that they would be nearly the same accuracy-wise and they both claimed to be making calibration file data available down to 5Hz... and I was really interested in getting the miniDSP for my subs, so I thought why not buy everything from the same company? Besides Cross-Spectrum mentioned something in their FAQ about the UMM-6 having a rather large noise floor compared to the EMM-6 (which I already have). The price difference never really made it into the equation at all for me... that small difference in price is just chump change really. And I guess it didn't hurt that REW had recently made the UMIK plug-n-play.

Right now the DevTeam and their supplier are looking into the below-20Hz data to see if they can suppy that data... IF they can include it into the calibration file I will be one happy camper and have no regrets for having gotten this UMIK.
 

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Right now they are looking into the sub-20Hz data... if they can include it into the calibration file I will be one happy camper.

Interesting enabling to have <20hz data without having the mic there?

How accurate would it be, maybe better not to have that <20hz data at all?
 

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Interesting enabling to have <20hz data without having the mic there?

How accurate would it be, maybe better not to have that <20hz data at all?
I believe they got all the raw data off those test rigs from 5Hz on up, just like they did for the first batch of UMIKs. They may have realized (or may be they even got some complaints? I don't know) that data that low in the freq spectrum isn't going to be reliable to the same degree as the above 20Hz stuff so they then made the decision to not publish it. I'm just guessing here since they haven't said anything specifically about what actually prompted the decision to remove that data from the calibration files other than the manufacturer believes the data to be unreliable. To me, unreliable simply means a larger tolerance factor is more appropriate but what that is no one's saying just yet. Basically anything can become reliable if the tolerance is opened wide enough.

...on that composite graphing of all the responses from second batch of UMIKs (see below) do you see how much they are varying just above 20Hz... so imagine what's going on below 20Hz. Sure they are not going to be able to hold a +/-.5dB down there but surely its got to be better than say +/-2dB... I think I'd even be thrilled with a +/-3dB.
 

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