Dayton OmniMic Precision Measurement System - Page 71 - AVS Forum
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post #2101 of 2112 Old 09-29-2014, 06:51 AM
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Originally Posted by Nabs17 View Post
Just received my Omnimic V2 system...got it setup and ran a FR for my LCR with test tracks 2,6 and 12 as recommended. I'll post the results here and ask if anything stands out to folks who are more familiar with interpreting results. A couple of things I think stand out...my LR are pretty similar but I have a couple of peaks in the center channel and a big dip at 10K.


So what stands out to you all?
Do you by chance have a receiver with Audyssey Dynamic eq and have it turned on? As another poster mentioned, you have some major bass boost going on.
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post #2102 of 2112 Old 09-29-2014, 11:24 AM
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Quote:
Originally Posted by primetimeguy View Post
Do you by chance have a receiver with Audyssey Dynamic eq and have it turned on? As another poster mentioned, you have some major bass boost going on.
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Originally Posted by jkasanic View Post
Are you using any form of EQ? Your bass looks boosted quite a bit but the general slope of your full range response looks pretty good. If you want to get more feedback on the measurements, your best bet might be to try using your OM mic with REW and post some spectrograms, waterfalls etc. in the REW thread. This isn't a knock against OM (I used to own it as well and still keep tabs on the thread for any updates) just that this thread doesn't get a lot of activity and when it does, it's mostly related to the software, test disc etc. and not evaluating in-room response. Be sure to read AustinJerry's guide before posting though. It will make taking measurements as simple as it is with OM and you'll know the guidelines for the graphs and charts which will facilitate the feedback from other members.
Thanks for the feedback. I looked at REW before but Omnimic just seemed easier....even though more expensive. I will look into the REW forum for information on reading/deciphering graph data because that's what I need.


The bass boost is man made I forgot that I had turned the gain up on my subs....so that's what is causing that. I also thought my general slope looked pretty good as well but wasn't sure.


Thanks again and I'll start reading the REW forum.

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post #2103 of 2112 Old 10-06-2014, 12:20 PM
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Taking Measurements Questions

Hi all,

I recently bought the OminiMic v2 kit, which also came with a free tripod and 5.1 DVD as part of a Parts Express promotion.

I am mostly interested in 1) finding the best possible location for my subwoofer, and 2) helping with room treatments selection and analyzing the before and after room treatments effects on frequency response and Bass Decay.

To that end, I tried to take measurements using the Bass Decay tab but I got stuck pretty quickly with some basic questions. I did go through the thread but did not find (or maybe simply did not understand) what I was looking for so apologies in advance for the stupid questions.

When I use the Bass Decay tab, it asks me to play tracks 4, 10, 6. Each track seem to be about 3 and a half minutes long.
- Am I supposed to play each entire track and in succession, or just one beep/cycle per track?
- Do I pause the graph in between tracks to take measurements?
- Does anyone have a glossary of which track correspond to what frequencies? (e.g. track xx measures 20 to 80Hz). I am mainly interested in the bass region of the frequency response and may not want/need to plot a full response.
- Is it possible to just measure a segment of the frequency response, e.g. 20hz to 200hz?

Likewise the Frequency Response Tab requires to have tracks 2, 6, 12 (7, 8, 13, 14) played.
- What does this mean exactly? Play the tracks in succession? Why are some of the tracks in parentheses?

By the way, interesting enough, the DVD operates differently from the CD. For Bass Decay, for instance, there is only one track to play per speaker.

Sorry, basic stuff, but I have never used a measurement software and I am totally confused. What I did in the past was playing a test CD (with either sinewaves or pink noise at specific frequencies) that I have and measure each level with an SPL meter (Galaxy) to plot a curve. A very laborious process, which I was trying to avoid.


Many thanks in advance for the help.
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post #2104 of 2112 Old 10-06-2014, 12:25 PM
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I thought the track listing was provided, or maybe check the help within the application. I know I have a printout of the tracks I keep with my kit. There can be multiple tracks that can be used for a given measurement/plot type, you use which ever one's you want. But for any measurement you just play the track and when you get your measurement saved you can stop it. Tracks are long just to allow you to make multiple measurements and tweaks without having the play the track many, many times.
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post #2105 of 2112 Old 10-06-2014, 12:30 PM
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Quote:
Originally Posted by primetimeguy View Post
I thought the track listing was provided, or maybe check the help within the application. I know I have a printout of the tracks I keep with my kit. There can be multiple tracks that can be used for a given measurement/plot type, you use which ever one's you want. But for any measurement you just play the track and when you get your measurement saved you can stop it. Tracks are long just to allow you to make multiple measurements and tweaks without having the play the track many, many times.
Thanks Primetimeguy. I did not find the track listing in the manual but will look again. I thought maybe each track only tests a specific frequency range? Thanks for your answer on playing a track only long enough to take a measurement. That's what I thought but I was not sure, very helpful. If you find the track listing anywhere, please let me know. Much appreciated!
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post #2106 of 2112 Old 10-06-2014, 12:44 PM
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Thanks Primetimeguy. I did not find the track listing in the manual but will look again. I thought maybe each track only tests a specific frequency range? Thanks for your answer on playing a track only long enough to take a measurement. That's what I thought but I was not sure, very helpful. If you find the track listing anywhere, please let me know. Much appreciated!
Thanks Primetimeguy, I actually found the listing! It was a link on the first page in the manual, totally missed it...That's great. Do you know what the end points are for bass, and mid-range when it mentions "bass" or "bass removed"? Bass goes from 20hz to 500 hz maybe? and mid range from 500 hz to 3khz? Thx.
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post #2107 of 2112 Old 10-06-2014, 01:52 PM
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Originally Posted by KB1 View Post
Thanks Primetimeguy, I actually found the listing! It was a link on the first page in the manual, totally missed it...That's great. Do you know what the end points are for bass, and mid-range when it mentions "bass" or "bass removed"? Bass goes from 20hz to 500 hz maybe? and mid range from 500 hz to 3khz? Thx.
I usually only do full range measurements so not sure. But quick measurement will tell you.
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post #2108 of 2112 Old 10-06-2014, 02:01 PM
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Originally Posted by primetimeguy View Post
I usually only do full range measurements so not sure. But quick measurement will tell you.
Got it . I will look at the parameters in the FRD file, should tell me what I need to know.

Do you know how loud the tones are recorded? I have been trying at -20db off reference level to be careful but not sure. My problem also is that the SPL readings are about 5-7db lower than my Galaxy SPL meter of RS. So I am not sure I can trust them. Weird no?
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post #2109 of 2112 Old 10-06-2014, 02:04 PM
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Got it . I will look at the parameters in the FRD file, should tell me what I need to know.

Do you know how loud the tones are recorded? I have been trying at -20db off reference level to be careful but not sure. My problem also is that the SPL readings are about 5-7db lower than my Galaxy SPL meter of RS. So I am not sure I can trust them. Weird no?
And I did use the correct calibration file using the serial number. The weird thing is measuring ambient noise in the room gives me about 40db (so normal) and about 2db less than my Galaxy meter. But measuring tones coming out of my receiver, the levels are almost 7 db off from the Galaxy or RS meters, 69.4db as opposed to 75db or 77 db using Galaxy or RS.
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post #2110 of 2112 Old 10-06-2014, 02:28 PM
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Quick question. The mic should be pointed up like an Audyssey mic?
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post #2111 of 2112 Old 10-06-2014, 02:56 PM
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I think most folks point it upwards (reading the thread). Someone was also mentioning that for subwoofer measurements bass is fairly non directional so up is ok but measuring in the higher range position matters more.
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post #2112 of 2112 Old 10-06-2014, 07:48 PM
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Well Lo and behold, I took some SPL measurements tonight and everything was fine! My readings were right on top of my Galaxy meter . No more deviations. Maybe just closing the software and reopen it did the trick. I had not closed it after importing the calibration file so maybe things needed to be reset. I can now take some frequency response measurements knowing that the readings are accurate
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