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Dayton OmniMic Precision Measurement System - Page 67

post #1981 of 2086
Quote:
Originally Posted by Phillips751 View Post

Please can someone advise on the procedure for measuring just the Speaker (not the Room) from 500hz - 20,000hz.

Thanks in advance
Take the speaker out to the back yard, put it on its back facing up, suspend the mic as high above it as possible. You don't have to worry about the room, as there isn't any.
post #1982 of 2086
Quote:
Originally Posted by Phillips751 View Post

Please can someone advise on the procedure for measuring just the Speaker (not the Room) from 500hz - 20,000hz.

Thanks in advance

You can get a pretty accurate measure by placing the mic 1/2-1m away and adjusting the gate time to 3ms or so.
post #1983 of 2086
Quote:
Originally Posted by jim19611961 View Post

You can get a pretty accurate measure by placing the mic 1/2-1m away and adjusting the gate time to 3ms or so.
The issue with having it that close is whether the sound fronts from the various drivers have integrated into a single coherent front. That can take a few meters, depending on the speaker. Accounting for that is one reason for measuring each driver individually nearfield, but then integrating the individual measurements opens a different can of worms.
post #1984 of 2086
Thank you all

Outside measurements are not an option.
Quote:
You can get a pretty accurate measure by placing the mic 1/2-1m away and adjusting the gate time to 3ms or so.
.

How do i adjust the gate?
Quote:
The issue with having it that close is whether the sound fronts from the various drivers have integrated into a single coherent front. That can take a few meters, depending on the speaker. Accounting for that is one reason for measuring each driver individually nearfield, but then integrating the individual measurements opens a different can of worms.

I was going to ask where abouts the mic is positioned height wise?

How would i measure each driver individually nearfield, then integrate the individual measurements,

Thanks in advance
post #1985 of 2086
Quote:
Originally Posted by Phillips751 View Post

Thank you all

Outside measurements are not an option.
.

How do i adjust the gate?
I was going to ask where abouts the mic is positioned height wise?

How would i measure each driver individually nearfield, then integrate the individual measurements,

Thanks in advance

The gate is labeled "only to" on the omnimic FR graph.

Nearfield individual driver plots require only connecting one driver at a time and measuring it.



You can then plot them together and get something like the above.
post #1986 of 2086
Ok, I ordered. Hope I can figure it all out when it arrives.
post #1987 of 2086
Quote:
Originally Posted by DaytonAudio View Post

Guys, we appreciate all of your comments and suggestions. When we were co-developing the OmniMic we spent numerous hours and resources trying to create a breakthrough measurement device. We feel we accomplished that. As we have added additional features and improved the product we have tried to keep costs down along the way. We do listen to you, most often without comment back to you. We perform recalibration of the mics for only the price of sending it back to us. We have improved the software and offered features not on the original release yet maintained the costs, though countless man hours were spent by Bill and our team creating and testing these improvements. We appreciate the users of the OmniMic and this forum as a vehicle to comment and improve the product and services we offer. If any of you need to communicate to us directly, you can email me, richt_at_daytonaudio.com anytime.

How does it compare to RTZ PRO II?
post #1988 of 2086
Quote:
Originally Posted by wse View Post

How does it compare to RTZ PRO II?


I think it depends on your usage e.g. Room or Speaker measurements?

Omnimic is more towards Speaker measurements, XTZ towards Room acoustics..
post #1989 of 2086
Quote:
Originally Posted by Phillips751 View Post

I think it depends on your usage e.g. Room or Speaker measurements? Omnimic is more towards Speaker measurements, XTZ towards Room acoustics..

ROOM ACOUSTICS smile.gif
post #1990 of 2086
Oh, I guess I should have done more home work. I'm interested in room acoustics and sub placement primarily. I'm guessing OmniMic will stilll suffice? I bought the OmniMic and just got it up and running last night. Now I'm a little like "Now what?"

Is there a better thread for "1) Do this sweep 2) Do this sweep?" Or just wade thru the 67 pages here? Be cool if there were threads dedicated to each measurement, how to do it and what it tells you.
post #1991 of 2086
Quote:
Originally Posted by mavericks64 View Post

Oh, I guess I should have done more home work. I'm interested in room acoustics and sub placement primarily. I'm guessing OmniMic will stilll suffice? I bought the OmniMic and just got it up and running last night. Now I'm a little like "Now what?"

Is there a better thread for "1) Do this sweep 2) Do this sweep?" Or just wade thru the 67 pages here? Be cool if there were threads dedicated to each measurement, how to do it and what it tells you.


You should be fine.

Read the help files in the program.

For sub/speaker placement it is great you can see live measurements.
post #1992 of 2086
Anyone know if there's a way to increase the capture time in Oscilloscope mode?

I'm trying to do a task for work, which is to determine the damping of a length of convoluted tubing by plucking it with the mic right next to it and observing the amplitude's decay rate.

The problem is that the ~90 Hz resonant freq is being modulated by a much lower freq.

In order to measure the decay rate accurately, I'd have to look at the waveform at points which are one cycle apart relative to the low freq, but 200 ms is only a small fraction of that.
post #1993 of 2086
Quote:
Originally Posted by noah katz View Post

I'm trying to do a task for work, which is to determine the damping of a length of convoluted tubing by plucking it with the mic right next to it and observing the amplitude's decay rate.
Could try recording the signal, trim it to start where you pluck it and import that to REW as a pseudo impulse response and run REW's modal analysis to get the decay rates of the resonances. Or just record the signal in Audacity and look at it there, but it is typically very difficult to get an accurate result that way if there is more than one resonant frequency.
post #1994 of 2086
I just went with the standard assumption of 2% damping ratio
post #1995 of 2086
I recently got the Omnimic v2. So far I understand very basic stuff, nothing that has really made me feel it's real investment yet to an auto eq that is very straight forward to its use. My room is also way to small to care about decay.

SO far my use has been this:

1) After doing my own front speaker distance apart testing for imaging (left to right), I had to adjust my distance away from the wall and took sweep measurements with one main channel individually after using 3 inch adjustments from the furthest point to the wall (just parallel with my TV) to about 2 feet out. I also used the right channel as a reference to see that they weren't very far apart to begin with.SO it was helpful to see the changes of these movements and pick the flattest out of them all, then place the other channel similirly in placement. Again, I wish it gave me some better approach, with all the stuff I see available.

2)Used Bass Decay a little, but only noticed huge peaks with each speaker around 50 hz, which I wouldnt even be used them at with a crossover point. Maybe it could help with setting parametric Eq filters inlcuding their Q value, but I couldnt seem to figure that out even with the help file. The other question, is if I do that, who's to say each speaker won't be completely off to the other once flattening response...? Even with smoothing, it seems like rocket science to set a average area for both speakers.

3)After setting that up, I set my gains using the spl tab and my Preamp pink noise. Anyone know a test noise on the Omnimic Disc? Great, but I could have done this quite cheaper with my spl meter already.

4)Took frequency responses with front channels to attempt to have the upper file tabs to help set my EMotiva UMC-200 parametric 11band eq with q gain. However, there are only six filters, and gave up trying to get the .frd charts it was asking for. Then questioned if having half my measurements would even work bettter than the auto-setup emo-q. Also I have no clue how to find optimal Q levels for my parametric eq with Omnimic, so again, I felt lost.

5) Just started placing my subs (dual 15's, one on the front of room, one in back) today to correct spl levels with the rest of my system, haven't had any other time, so I'm assuming I'd look at bass decay and frequency response again with this to see live action responses. But very confused on how this would speed up placement.... Maybe it is just there to clarify proper response from 1-200hz region to confirm good positioning. Hoping I can just use a test tone of where I expect my crossover points to be and then verify highest spl with that for the subs to pick the correct phase point??

After all of this, maybe someone can give an order of process when doing a full system setup, but I guess that is what makes experience a must with this OMNIMIC system. Glad I never spent more for a real RTA though, I guess I'd have to have someone consult for me just to really get the use out of this.


*** Any insight on all of this ranting would be helpful if any of you new V2 Omnimic users are out there.***
post #1996 of 2086
To start with

1. Use the full range frequency sweep for each speaker, left and right. to find the best speaker/listening location.

2. When you are EQing 0 -250hz you are EQing the room, when EQing 250hz - 20,000hz you are EQing the speakers themselves..

3. Once you have found the positions, EQ both speakers (mono) 0 - 250hz applying the same filters.

4.. Most likely you will use most of your filters in the 0 - 250hz range where most problems occur.

5. Check the bass decay to check your locations.

Hope this helps a bit
post #1997 of 2086
What filters are you describing, the 1/3rd,1/6th type scaling? SO focus only on the 250hz and up peaks it sounds. I will post my freq sweeps for you shortly when I will be doing them tommorow. I"m assuming I would pick the average and snapshot button for each to graph first, then see if you can guide me to the next steps, even though I tried to use the functions on the file menu/help section process for finding corrections. Step by step will probably be best! Also for bass decay, would I be looking for the least decay across the 0-250hz range or throughout 250hz-20,000 hz range? I have just posted (using disc 2 short sine sweep) left and right sine sweep averages. By the way, I also have the 5.1 disc aswell. WOuld the pseudo noise on that help set spl gains for each speaker? My emotiva pink noise can only generate to 73-74 decibels on the least sensitive surround speakers which max out the gain at that level.



Left main channel

Right main channel



**IGNORE THESE GRAPHS*** NEW GRAPHS ARE NOW POSTED AHEAD ON PAGE 68***
Edited by pnutbutter81 - 6/2/13 at 1:05pm
post #1998 of 2086
For backround info, Pics of my current room setup from 360 degree rotation:








DImensions: Front to Back: 177"
Left to RIght: 145"
Height: 97"

Front channels approx 7.8 ft apart and very close to that for listening position (only one): I will repost my measurements again with long sweeps, as I have changed my room configuration and put in dual subs front and back and provide those sweeps aswell.
Edited by pnutbutter81 - 5/31/13 at 3:04pm
post #1999 of 2086
Quote:
Originally Posted by pnutbutter81 View Post

For backround info, Pics of my current room setup from 360 degree rotation:








DImensions: Front to Back: 177"
Left to RIght: 145"
Height: 97"

Front channels approx 7.8 ft apart and very close to that for listening position (only one): I will repost my measurements again with long sweeps, as I have changed my room configuration and put in dual subs front and back and provide those sweeps aswell.

Are these measurements taken for best speaker/listening location or as currently setup?
Use toe in to help with the high end.
Get the main speakers right first before you change any other speaker (sub included)

Please list your gear.

Observation, correct me if i am wrong please.
This is a bedroom?
Speakers are not evenly spaced?
A lot of soft items (bed, clothes etc)?
Are you restricted with speaker/listening location?


Can you not put your gear in a lounge?
Ideally with removal/change off clothes etc is going to interfere. Soft items alter high end as well as hard this is more with reflections.

All you can do is work with what room you have.

Rooms have the most influence on sound.
You can have a pair of $20,000 speakers setup incorrectly and a pair of speakers worth $2,000 setup correctly and the $2,000 speakers will sound a lot better.
post #2000 of 2086
Some extra questions that arise in my thoughts through setup procedures:

Should frequency sweeps be tested after initial trim is set to 75db standard, eq’s on receiver set to bypass, crossovers (on my receiver) disengaged to run speakers being measured full range?

Unless using 5.1 disc keep all signals at stereo mode?

Can 5.1 test disc be used in place and still utilize everything disc 2 covers?

What test can be used for setting speaker gain levels in spl mode?
post #2001 of 2086
Quote:
What filters are you describing, the 1/3rd,1/6th type scaling?

I wasn't talking about scaling.
i was talking about EQing filters with there Center Frequency, Q, Gain.

When taking measurements adjust to 1/12 octave smoothing this will give you more detail. Unfortunately it defaults to 1/6 octave smoothing, which is to smooth for me.
Quote:
SO focus only on the 250hz and up peaks it sounds.
First find the smoothest across the whole frequency spectrum, but concentrating more on the 0-250hz range where the most problems occur.
When looking at 0 - 250hz region use both main speakers playing (mono), but also look at individual to see the possible offending speaker / location.
The reason you need to start of with the best mains/listening location for each main speaker is to minimize using to much EQ.
This take time but you know where you stand and have to deal with.
Quote:
I will post my freq sweeps for you shortly when I will be doing them tomorrow

No worries, but make sure when you do they are maximized for best location.
Don't forget that listening position has a influence as well, people can bypass this.
Quote:
I"m assuming I would pick the average and snapshot button for each to graph first,then see if you can guide me to the next steps, even though I tried to use the functions on the file menu/help section process for finding corrections.
If you are talking about finding the best location then no, you want it to be in "Real Time".

But if you are talking about once you have found the best possible locations then yes with the 1/12 octave smoothing.
Quote:
Step by step will probably be best!
Absolutely, first is as above.
Quote:
Also for bass decay, would I be looking for the least decay across the 0-250hz range or throughout 250hz-20,000 hz range?
Bass 0 - 250hz, bass does go above this, but this range is the most problematic.
Quote:
I have just posted (using disc 2 short sine sweep) left and right sine sweep averages.
Yep that's OK, you say average not sure what you are using, do you mean multiple listening positions, or snapshot?
Quote:
By the way, I also have the 5.1 disc as well.
I don't have this disc, but could come in handy for the distance settings, i hear it is better than the other disc. Not much on this disc though.
Quote:
WOuld the pseudo noise on that help set spl gains for each speaker? My emotiva pink noise can only generate to 73-74 decibels on the least sensitive surround speakers which max out the gain at that level.
Use the test tones in the receiver for setting levels.
Even the auto settings are pretty good these days.
post #2002 of 2086
Quote:
Are these measurements taken for best speaker/listening location or as currently setup?

I have only one listening position, and it is center of room at the burgundy chair. And am trying to keep the tv stand centered in the room as close to a a/c register to not cover it up (right next to window). The room is multiuse, the furniture is probably going to be there till I move. The surround speakers can't be moved, and must stay as is, but will use bookshelf speakers with stands in a future setup, identical to the surround back speakers.
Quote:
Use toe in to help with the high end.
The speakers have such close proximity and great off axis response, I have no need to toe-in, which I've done in the past. RBH tech also recommend no need for toe-in even though I have experimented..
Quote:
Get the main speakers right first before you change any other speaker (sub included)

SO far, I have maxed out the front channels equidistant to the sides of the room to the 1/2 inch, approximately 15.5" from the TV edge before it hits the desk to the left or dresser on the right. I have not yet determined that I have it the correct distance from the front wall. I have decided to take it no further back than parallel to the TV screen to avoid any obstacle to imaging. SO I have started from that point distance wise and have moved the left main speaker in 3 inch increments while I took measurements for the first time with omnimic short sine sweeps and just guessed with the measurements at hand to about a foot and a half out before it hits the desk on the left side, it still looked better frequency wise, then I just replicated the right channel at that distance from wall equidistant from the tv edge and leveled. SInce this was my first experience with the omnimic I really had no expeirence yet. I did have the mic at my measured listening position though...
Quote:
Please list your gear.

Preamp: Emotiva UMC-200
Amp: 5 channel Emotiva XPA-5 (200wx5ch@8ohm/400wx5@4ohm)for all speakers (Just recently upgraded and now can only do 5.1, so back surrounds are not in use as of now)
L/C/R: Status Acoustics Mediettes (4 ohm), center is not ported, but mains are dual ported on back. Center is seated on auralex mopad, mains are on Plateau Stands.
Surrounds: RBH WM-30 (8ohm), can't change placement for now.
Subs: (2) PowerAudio XS-15 (500w), just acquired, so far it seems front and back wall configuration is smoothest without any measurements and phase has not been checked, but is at 0 with levels set to all other speakers, tuned each to that
Universal Player: Oppo bdp-83
APC H15/H10 Powerconditioner is connected to all but the Poweraudio Sub toward back wall.
Impact Acoustics Sonicwave interconnects, Impact Acoustics Velocity Velocity Speaker Cable.
Quote:
Observation, correct me if i am wrong please.
This is a bedroom?
Speakers are not evenly spaced?
A lot of soft items (bed, clothes etc)?
Are you restricted with speaker/listening location?


Yes, in a 2 story house. Speakers are evenly spaced from centerpoints (tv, which is sitting near dead on center of room. WIndow is not centered to room.

Yes, I have ALOT of stuff in this room to deal with, but have to work with it, I try to keep everything put away for the most part, but always keep the closet open out of habit with a coffee table I had to move to place the sub on the back wall. I can close the left part of it during measurements though. I don't expect to have the best acoustics with these obstacles in mind, just optimize as much as I can:)

Yes, listening position is set at Burgundy recliner dead center for most part halfway into room. No other real way to move it with the bed in the way. And no other room I can put this system in for now, and maybe a while:( Perhaps a nice apartment soon where I can dedicate a room and not a bedroom.
Edited by pnutbutter81 - 5/31/13 at 7:30pm
post #2003 of 2086
Quote:
Should frequency sweeps be tested after initial trim is set to 75db standard, eq’s on receiver set to bypass, crossovers (on my receiver) disengaged to run speakers being measured full range?

Everything should be turned off including crossovers etc for finding the best locations.
Use the receivers volume to adjust so the frequency response is stable (not shifting up or down etc). Outside noise etc can interfere that the mic picks up that our ears don't hear. Mics are more sensitive than our ears.
Quote:
Unless using 5.1 disc keep all signals at stereo mode?
Continue to use the other disc for the initial tests.
You want the same signal going to each speaker.
Quote:
Can 5.1 test disc be used in place and still utilize everything disc 2 covers?
Not sure don't have this disc.
Quote:
What test can be used for setting speaker gain levels in spl mode?
Use the receivers test tone, normally they are centered around 1,000hz.
Try the auto setting in the receiver they normally are pretty good.

You have loaded the Omnimic calibration file?

Keeping in mind we are only looking at the most important speakers at this stage (mains) then look at the center etc
post #2004 of 2086
I did notice, because I took pictures on an angle, it even looked to me that everything seems placed awkward, but if they were more from my listening seat, they'd be dead on equal to the inch.
Quote:
You have loaded the Omnimic calibration file?

Keeping in mind we are only looking at the most important speakers at this stage (mains) then look at the center etc

Yes, specific to my mic code as directed. I will redo these main sweep measurements. But keep my distance apart for mains at the same due to constraints of needing the sub to fit in between the right main and tv. SO, i will just make distance from wall changes with your new tips.
post #2005 of 2086
With the listening position in mind this is going to cause nulls etc. Middle of the room is not ideal and can cause lack of bass.
Are those measurements of just the mains playing individually or are the with the subs playing as well?
When we get to the subs phase/ distance setting will come in to play as well.

As a ball park people tend to look at the the of thirds as a starting point.
As a starting point thirds are good for main speaker/sub locations.
Sub locations can be improved with center of walls e.g. center of front and rear wall.

Does the receiver have EQ?

With the distances/locations optimized post the three main measurements (L speaker only, R speaker only, then L&R combined) with 1/12 octave smoothing.

When measuring don't close / shift anything that you wouldn't when listening, keep it as is if you were listing as much as possible.

Try closing that door for measurements, easy to adjust when listening and could be a advantage.
Edited by Phillips751 - 5/31/13 at 7:58pm
post #2006 of 2086
Correct me if I'm wrong on the main speaker placement (I will not be able to change the distance apart from speakers, as it would not allow for sub placement and is nearly close to the golden traingle for listening position):

Step 1:
1) using mono long range sine sweep signal to each main channel speaker separately(no eqing/flat), using 1/12th octave smoothing, look for the smoothest response from 250hz-20hz, using about 3" increments from the wall, but beyond my tv screen. Don't bother with 0-250hz range or bass decay during that? Or all three should be looked at during this?
post #2007 of 2086
Quote:
Are those measurements of just the mains playing individually or are the with the subs playing as well?
When we get to the subs phase/ distance setting will come in to play as well.

Those are without the subs playing and each main speaker individually, and there is an average button just below the graph that will average the last number of played sweeps on that speaker. I did about 7 short burst sine sweeps (full range though) then averaged each channel seperately.

All tests I do will be without the subs on.

Also the door will be closed and everything will be set as usual when listening.
Quote:
As a ball park people tend to look at the the of thirds as a starting point.

Currently the speakers are about a 1/5 distance of the room width from side walls, any further would hit the TV.
Quote:
Does the receiver have EQ?

Yes, It allows up to 11 band parametric eq points (from 20.27hz value to 20,000somethinghz values) , with a q value for each allowed. For each speaker it also allows a slope and crossover setting. It will let me use almost any frequency for the 11 band parametric, but it wont do dead on values, lol.

When I take values tommorow. Would files help more than graphs to help input later on filters? I will provide the left and right channel measurements each/then together at about 4 different distances I have room for. But I can also save .frd files too if needed for each of those.
Edited by pnutbutter81 - 6/1/13 at 4:19pm
post #2008 of 2086
Quote:
Correct me if I'm wrong on the main speaker placement (I will not be able to change the distance apart from speakers, as it would not allow for sub placement and is nearly close to the golden traingle for listening position):

The rule of thirds is a guide (good starting point), you have to find the best placement for your room.

Because the speakers are rear ported the rear wall is going to cause problems if not setup properly. At a later time this is where the subs + crossover can come in to effect depending on setup.
Quote:
Step 1:
1) using mono long range sine sweep signal to each main channel speaker separately(no eqing/flat), using 1/12th octave smoothing, look for the smoothest response from 250hz-20hz, using about 3" increments from the wall, but beyond my tv screen. Don't bother with 0-250hz range or bass decay during that? Or all three should be looked at during this?

1. Use track 2 (Monophonic Short Sine Sweep) for both speakers combined. The most important part of this measurement is 0 - 250hz (approx).
2. Use track 6 (Monophonic Short Sine Sweep Left) for Left channel only
3. Use track 12 (Monophonic Short Sine Sweep Right) for Right channel only
4. Look at the decay after to get an idea how it works. This is very handy for the subs where decay is important.

Using 1/12 octave smoothing

Looking for the smoothest across the full range (0 - 20,000hz). From about 250hz down try to get the best you can, you won't get flat, keep this in mind.

How does it currently sound, forgot to ask you.
I mean does it sound boomy, forward, bright etc.
Do you listen to music or movies in percentage.
post #2009 of 2086
Quote:
Those are without the subs playing and each main speaker individually, and there is an average button just below the graph that will average the last number of played sweeps on that speaker. I did about 7 short burst sine sweeps (full range though) then averaged each channel seperately.

Personally i wouldn't worry about the averaging, this is for different listening positions. Also takes up unnecessary time.

Do as many measurements in one session as possible because you won't be able to get the mic in exactly the same position.
Quote:
All tests I do will be without the subs on.

Good at the moment.
Quote:
Also the door will be closed and everything will be set as usual when listening.

Good
Quote:
Currently the speakers are about a 1/5 distance of the room width from side walls, any further would hit the TV.

Do the best you can, we all have restrictions unless having a dedicated room. Fifths are ok,
Play around with toe in.
Quote:
Yes, It allows up to 11 band parametric eq points (from 20.27hz value to 20,000somethinghz values) , with a q value for each allowed. For each speaker it also allows a slope and crossover setting. It will let me use almost any frequency for the 11 band parametric, but it wont do dead on values, lol.

Does it have 11 filters for each channel or in total?

When I take values tommorow. Would files help more than graphs to help input later on filters? I will provide the left and right channel measurements each/then together at about 4 different distances I have room for. But I can also save .frd files too if needed for each of those.[/quote]

Yep send the .frd files + post graphs, someone else might like to chime in.

I can determine the filters that you can set in the receiver.

Does your receiver have auto PEQ, level and distance settings?
Edited by Phillips751 - 6/1/13 at 10:02pm
post #2010 of 2086
Yep send the .frd files + post graphs, someone else might like to chime in.

I can determine the filters that you can set in the receiver, although doing the EQ on the fly in real time could be better.
Another way is to give you PEQ filters with Q and Gain then you can fine tune in real time.

Does your receiver have auto PEQ, level and distance settings?
Edited by Phillips751 - 6/1/13 at 10:03pm
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