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Dayton OmniMic Precision Measurement System - Page 63

post #1861 of 2086
Quote:
Originally Posted by Phillips751 View Post

Quote:
Originally Posted by mfrey0118 View Post

Question, does it matter where i point the tip of the mic while measuring at listening positions for overall home theater EQ?


Pointed at the speakers, with a slight lift.

Don't people recommend pointing it straight up and leaving it there for measuring all speakers?

post #1862 of 2086
Quote:
Originally Posted by primetimeguy View Post

Don't people recommend pointing it straight up and leaving it there for measuring all speakers?

Straight up.

Yep, that's what I do, .... unless I'm performing near-field work.
post #1863 of 2086
Quote:
Originally Posted by Phillips751 View Post

Tried to use the main maths function (Offset) to find the differemce between two frequency resposne graphs, but it doesn;t seem to be working.
Can someone please describe the procedure to do this?
Thanks in advance

Offset just offsets the main curve up or down. The function you want is normalize.
post #1864 of 2086
Quote:
Originally Posted by FOH View Post

Straight up.
Yep, that's what I do, .... unless I'm performing near-field work.
I do straight down since I can't get the mic in the right position where my head ends up with the mic pointing forward or up without getting microphonic effects via the stand or cable.
post #1865 of 2086
Just a heads up that this is the DOTD at PE today for $199.00 with a free mic stand!!
Edited by Mazeroth - 12/21/12 at 7:54pm
post #1866 of 2086
Quote:
Originally Posted by Mazeroth View Post

Just a heads up that this is the DOTD at PE today for $199.99!

Wow! Seriously, thanks for the heads up!!! Ordered...finally. smile.gif
post #1867 of 2086
Ok i was told to point at the source due to high frequencies

Maybe Bill can kick in here.
post #1868 of 2086
Quote:
Originally Posted by Phillips751 View Post

Ok i was told to point at the source due to high frequencies

Maybe Bill can kick in here.

If I recall correctly Bill had previously confirmed in this thread that the mic should be pointed at the ceiling. It is possible though that I'm having a fifties moment this morning. smile.gif
post #1869 of 2086
Quote:
Originally Posted by rx-8 View Post

If I recall correctly Bill had previously confirmed in this thread that the mic should be pointed at the ceiling. It is possible though that I'm having a fifties moment this morning. smile.gif
The mic is omni-directional. The typical positioning is at a 90 degree angle to the source, whether that's with the mic vertical, horizontal or anywhere in between doesn't matter.
post #1870 of 2086
Should I be using 1/6th smoothing or 1/12? I hope 1/6th is more like what our ears hear, because I have a dip at 100hz that is 6 db lower using 1/12 smoothing than it is using 1/6th smoothing.

thanks
post #1871 of 2086
I use at least 1/12 when I'm measuring to optimize my system. I've read evidence that nulls are audible at greater than a 1/6 resolution. Ethan Weiner has some good reads on his site on the topic.
post #1872 of 2086
You know, you can easily see for yourself the difference between where the mic is pointed...

1) Measure one speaker with the mic pointing upwards (but still only a few feet from the speaker). Set the windowing (red part) in the lower impulse response plot so it ends just before the first big reflection (click there, its usually about 3 to 5 msec after the main impulse action). Probably use third octave or so smoothing. Save the file ("File".."Save Curve").
2) Point the mic right at the speaker, go into the "Main Math" menu, choose "Normalize" and select the file you just saved.

voila, the difference in response appears in the graph of what the mic sees.

There will be some difference in the plots above 10kHz or so.... the capsule diameter is very small (6mm) but still finite -- it works pretty much the same as Baffle Step except with a mic instead of a speaker.
post #1873 of 2086
I'm planning on buying the OmniMic V2 tomorrow (12/26). How long does it take to receive it? I'm in Georgia.

Thanks!
post #1874 of 2086
Quote:
Originally Posted by bwaslo View Post

You know, you can easily see for yourself the difference between where the mic is pointed...
1) Measure one speaker with the mic pointing upwards (but still only a few feet from the speaker). Set the windowing (red part) in the lower impulse response plot so it ends just before the first big reflection (click there, its usually about 3 to 5 msec after the main impulse action). Probably use third octave or so smoothing. Save the file ("File".."Save Curve").
2) Point the mic right at the speaker, go into the "Main Math" menu, choose "Normalize" and select the file you just saved.
voila, the difference in response appears in the graph of what the mic sees.
There will be some difference in the plots above 10kHz or so.... the capsule diameter is very small (6mm) but still finite -- it works pretty much the same as Baffle Step except with a mic instead of a speaker.

Well yes, but the question is, which way most accurately measures the room response (pointing strait up or pointing strait ahead).

Sure one can see the difference, but which is more true? Which setup is the mic designed for?
post #1875 of 2086
Quote:
Originally Posted by carp View Post

Should I be using 1/6th smoothing or 1/12? I hope 1/6th is more like what our ears hear, because I have a dip at 100hz that is 6 db lower using 1/12 smoothing than it is using 1/6th smoothing.
thanks
Use whatever your EQ is capable of doing. If you're using a parametric that allows you to set Q to 1/12 octave then use it, but if you have a 1/3 octave EQ there's no point in running more than 1/6 octave smoothing
Quote:
. Well yes, but the question is, which way most accurately measures the room response (pointing strait up or pointing strait ahead).
Neither. You can move the mic position a half inch and get a different result, and the same applies to your listening position, so there's no point in trying to get it 'perfect', because there is no perfect.
post #1876 of 2086
Quote:
Originally Posted by carp View Post

Should I be using 1/6th smoothing or 1/12? I hope 1/6th is more like what our ears hear, because I have a dip at 100hz that is 6 db lower using 1/12 smoothing than it is using 1/6th smoothing.
thanks

Personally I recommend 1/24th. You want to see what the room is really doing, 1/6 in particular masks many features and gives a inaccurate picture of what is really going on. When you smooth the peaks and nulls, you simply just dont see them as they really are.
Edited by jim19611961 - 12/28/12 at 11:01am
post #1877 of 2086
But a fair bit of research (see Toole) indicates that the narrow high-Q peaks are much less audible than the wide low-Q ones of same amplitude. There's not a lot of point in measuring what doesn't much matter, at least for EQ purposes. If the peaks and nulls are from reflection then ETC is more relevant.
post #1878 of 2086
Quote:
Originally Posted by bwaslo View Post

But a fair bit of research (see Toole) indicates that the narrow high-Q peaks are much less audible than the wide low-Q ones of same amplitude. There's not a lot of point in measuring what doesn't much matter, at least for EQ purposes. If the peaks and nulls are from reflection then ETC is more relevant.

My point is you wont know the true amplitude of the peak/null with 1/6 or 1/3 octave smoothing and perhaps not with 1/12 either.

I will add though that most serious room peaks and nulls are caused by reflections and by room modes. Most of the time, the speaker itself is not the culprit.
post #1879 of 2086
Quote:
Originally Posted by bwaslo View Post

There's not a lot of point in measuring what doesn't much matter,
Or that which you can't fix. Oddly though often the same guys who claim to be able to hear things that can't be measured will drive themselves nuts over things that can be measured but aren't very well heard, if at all.
post #1880 of 2086
TRUTH, master yoda. You really do have a high level of midiclorians
post #1881 of 2086
Quote:
Originally Posted by beastaudio View Post

TRUTH, master yoda. You really do have a high level of midiclorians
I prefer a high level of Scotch. wink.gif
post #1882 of 2086
Quote:
Originally Posted by Bill Fitzmaurice View Post

I prefer a high level of Scotch. wink.gif

Scooped the pops a nice bottle of 18 yr Glenlivet for the holidays. There isn't much left tongue.gif
post #1883 of 2086
Wow! Received my Omnimic from PE yesterday and so far I am extremely pleased. I've only had about 30 minutes to play with it so far and I'm hooked big time, the real time in-room response is indispensable. I can see instantly where I need correction, in my case I have only two dips at 500Hz and 1200Hz.
post #1884 of 2086
It was almost exactly a year ago I got mine and felt the same way about it. Happy measuring smile.gif
post #1885 of 2086
I sent my mic in from v.1 and got it back with numbers on it but nothing that matches the 6 digit code that the software requires. Anyone (Jonathan?) that has done this how did you input the calibration file? I am retired now and have time to learn this.
post #1886 of 2086
^^
You will need to download the calibration file from here:

http://www.daytonaudio.com/index.php/test-measurement/omnimic-v2-precision-measurement-system.html

Also, you will need to upgrade the OM software to Version 2 at least...


**EDIT** Here is the link for Version 4 or you can e-mail Dayton Audio/Parts Express for a copy:
Quote:
Originally Posted by bwaslo View Post

Pre-official-download of the new version of Omnimic software. I'll be doing a short talk on this at the MWAF next Saturday.
http://www.libinst.com/Omnimic/OmniMicInstall.exe
--
Features in this version:
  • Automatic (or manual) equalization parameter export to MiniDSP, can work on average responses at multiple seating positions.
  • Built-in Z-Axis offset calculator for determining depth differences between tweeters and midranges, allows accurate crossover design.
  • text notes can be added onto Snapshot files for publishing online
  • Speech Transmission Index (STI) and RASTI calculated in the Energy Time Curve display.
  • Dual tone sine/square wave generator for computer soundcard
  • Zooming, smoothing, and multiple curves in the ETC plot.
  • Can download microphone calibration files directly from the web.
  • Longer time lengths supported in waterfalls and Wavelet spectrograms for room analysis
  • 690msec WAV file export for impulse responses
  • Phase display in Added Curves
  • Easy curve splicing (such as joining tweeter and woofer curves) for display
  • New math function for main curve: vector sum with data from saved FRD files, with delay adjustment
  • Compatible with V1 or V2 hardware

Edited by laugsbach - 1/4/13 at 1:28pm
post #1887 of 2086
Quote:
Originally Posted by laugsbach View Post

^^
You will need to download the calibration file from here:
http://www.daytonaudio.com/index.php/test-measurement/omnimic-v2-precision-measurement-system.html
Also, you will need to upgrade the OM software to Version 2 at least...
**EDIT** Here is the link for Version 4 or you can e-mail Dayton Audio/Parts Express for a copy:

I hope the 5.1 DVD or preferably 7.1 BluRay comes out in the next month or so. At least on the Audyssey thread, there's a mini-revolution toward using REW for post-calibration assessment, in large part due to the new ability to utilize USB mics, pick individual channels to test via ASIO4ALL & HDMI, and to use one measurement to generate multiple types of graphs.

OM may be easier to use and possibly more stable, if I compare my OmniMic experience to what I'm reading on other threads, though.
Edited by sdrucker - 1/4/13 at 2:47pm
post #1888 of 2086
Quote:
Originally Posted by laugsbach View Post

^^
You will need to download the calibration file from here:
http://www.daytonaudio.com/index.php/test-measurement/omnimic-v2-precision-measurement-system.html
Also, you will need to upgrade the OM software to Version 2 at least...
**EDIT** Here is the link for Version 4 or you can e-mail Dayton Audio/Parts Express for a copy:

It is not showing my serial number as valid and mine is version 1. I have written parts express.
post #1889 of 2086
I have a Version 1 OM that I sent back to PE as well and my serial number is listed as valid on my link above....strange!

I don't think it will help, but you could try the web s/n lookup feature in OM Version 4...
post #1890 of 2086
Quote:
Originally Posted by sdrucker View Post

I hope the 5.1 DVD or preferably 7.1 BluRay comes out in the next month or so.

AMEN to that! smile.gif

I hope PE is reading all the posts over at HTS about REW software with the USB mics...
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