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Hi All, new to the forum. I used the PE OmniMic for a bit (borrowed from a friend) and was going to buy one but found this instead. I was shipped yesterday. I have no idea how to use REW so I need to dig into that.

I am looking forward to hearing the answer to sdurani question.
 

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Most laptops I've seen don't have a line out but instead a headpone out. Can that be used to send the REW sweep signal to the receiver/pre-pro or is that output equalized for something like speech intelligibility? The reason I'm asking is because I had read that the line input on a computer is different from a mic input, with the difference being that the latter was equalized for speech (on-line gaming, teleconferencing, etc). Wanted to know if that was the same for line out vs headphone out because I'll be able to connect the UMIK-1 to my laptop via USB for input signal, but only have a headphone jack for output signal. (Trying to retire my M-Audio Mobilepre USB.)
The headphone out should be fine. I've never heard of a headphone out being optimized for anything. The only thing that will influence the headphone out is the quality of the sound card.
 

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No problem, enjoy the mic. If you have any problems just contact miniDSP. I had an issue and they are working with me to get it all sorted out.
 

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I use a USB mic and it works very well with my laptop sound card (which i was able to do a calibration file as well)?

To calibrate my laptops sound card (Vista OS) i had to disengage the effects, then it all worked.
The laptop had a headphone out + mic in.

Also had to change to a single sweep. (for my mic i did).

Adjust the levels in & out (mine is set to 50 mic + 60 speaker (headphone) out.
 

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I received my UMIK a couple of days ago, and whilst it works exactly as advertised with the WIndows version of REW, it seems to have a few issues with the Mac version. Which is a little disappointing as that is why I bought it.

When using it with OS X Lion and my Mac Mini, it defaults to 48K format and I had to change the sample rate to 48K in REW. However, whilst I could make a measurement, there was something drastically wrong with the FR, with a massive roll-off below 1khz.

I replicated this with my Macbook Air.

After some fiddling about, I found that if I switch the sample length in the measurement window from 256K to 128K the FR was as expected and the same as the Windows version.

However, the question is what effect reducing the sample length will have on accuracy?

That aside, the calibrated response seems to be more accurate than my uncalibrated ECM8000, especially at the top.

Fuzzmeasure seemed to be fine.

Here's a pic of the issue with a 256K sample length.
 

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The headphone out should be fine. I've never heard of a headphone out being optimized for anything. The only thing that will influence the headphone out is the quality of the sound card.
Would you recommend the headphone out over an HDMI connection?
 

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Would you recommend the headphone out over an HDMI connection?
I wouldn't expect any difference, but try both and see if there are any meaningful differences.
 

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However, the question is what effect reducing the sample length will have on accuracy?
Longer sample length gives better signal-to-noise ratio, better immunity from the effects of minor background noise. Using the multiple sweep option is another way to get the same effect.

Edit: I have no explanation for the weird frequency response with the 256K sample length, that is a head scratcher. Have you gotten the same result more then once that way?
 

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UMIK on top calibrated behringer on the bottom.

EMP-E-41B/Crown XLS2500/macbook pro soundcard

 

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- Will there ever be a way ( & are you able to create a soft-patch within future releases of REW ) to use these new USB based microphones in conjunction with, REW's option to "Use loopback as a timing reference" ?
It might be possible to use ASIO4All to make a composite ASIO device that uses another soundcard path for the loopback return, but I haven't had a chance to try that yet.
 

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Longer sample length gives better signal-to-noise ratio, better immunity from the effects of minor background noise. Using the multiple sweep option is another way to get the same effect.

Edit: I have no explanation for the weird frequency response with the 256K sample length, that is a head scratcher. Have you gotten the same result more then once that way?
Yep. With the Mac Mini over several sessions and my Macbook Air.

Going to longer samples makes it even worse as the roll- off starts at 2k.

I hope it is a REW/Umik thing that can be fixed in an update (since Fuzzmeasure is fine) but now I've worked it out at least I can work around it by doing multiple sweeps.
 

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wow awesome results Fuzz, thanks for posting that
Indeed. In spite of the issues I've mentioned, the performance of the mic seems great.

My ECM8000 is not individually calibrated, and the generic REW cal file actually makes the response worse. The Umik out of the box does not have its deficiencies and tracks my calibrated ARC mic well.

Once you add the cal file it feels even more trustworthy.

My only other beef is the short USB cable. 2m is nowhere near enough.
 

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UMIK on the top Behringer on the bottom, this time in the sub frequencies. Outlaw LFM-1 EX. I also had the sub connected to an anti-mode dual core. I'm still getting the hang of the anti-mode, but you get the idea. Pretty similar.

1m



1in



LP

 

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What would be the difference between USB mics, i use the Omnimic?
A few db, a few Hz, nothing too significant. I know I read somewhere the UMIK-1 has more information in the cal file, but don't quote me on that.
 

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As a quick update, I contacted miniDSP about getting a new box and they told me it would be easier to just send me a new mic, but that I'd have to return the one I have. I asked them a question about the return process and they haven't responded since. It's been about about a day since I sent the e-mail, hopefully they get back to me soon so we can get this over with.
 
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