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Dayton OmniMic Precision Measurement System - Page 54

post #1591 of 2086
Quote:
Originally Posted by Phillips751 View Post

Thank you James.
The POS 2 seems to have the most differential.
Where these taken with the subs only?

The 5 graphs above are subs only.

I agree that position 2 has the most variance in it.

Below are two screen shots showing the measurements being overlayed each other.

The black trace is from 1-14-2012
The red trace is from 3-26-2012

As you can see if I move the red trace up by 3db most of the position 2 is pretty close and position 3 is almost dead on. That is what I was looking for since I know the mic location was different between my measurements from January and this month.

James
LL
LL
post #1592 of 2086
how do you overlay two different graphs in OM like that?
post #1593 of 2086
Quote:
Originally Posted by beastaudio View Post

how do you overlay two different graphs in OM like that?

BA,

If you notice in my screen shots the little window where it shows the colors and stuff, there is the "offest" section.

So I load the first frd file, then when I load the second one, I increase or decrease the offset and it raises or lowers it.

Hope that help.

James
post #1594 of 2086
Quote:
Originally Posted by exojam View Post

These only go to 10HZ since the mic was not calibrated to 5HZ until I sent it in.

I've got an updated mike and my graphs still only go to 10 Hz.

Yours go to 5?
post #1595 of 2086
Quote:
Originally Posted by noah katz View Post

I've got an updated mike and my graphs still only go to 10 Hz.

Yours go to 5?

Noah,

Did you download the latest software?

James
post #1596 of 2086
Quote:
Originally Posted by Phillips751 View Post

What i do is turn off speaker A (mains) and then run the sub at full range, using the receivers volume.

Can you give me some idea of how you do this?

Quote:
Originally Posted by elee532 View Post

I disconnected by FR and FL speakers. I set my receive volume to -15 and turned off Audyssey/EQ. I selected the Frequency Response tab with the following settings:
  • Sine Sweep
  • Blended 5.0 msec
  • Smoothing = None

I then played Track 2 (Monophonic Short Sine Sweep) from the test CD, right clicked and chose Save Snapshot to Graphic File. My result is attached.

So, aside from your point above about running the sub full range, are you saying that for the most part based on the steps I described above I am at least using the OmniMic correctly?
LL
post #1597 of 2086
elee532,

A few things to suggest for your measurements are:
1) Have your receiver or pre in stereo mode
2) Scale your graphs to either a 5db or 10db size
3) Change smoothing to 1-6th or 1-12th

To scale the graphs use the little icons in the top left of the screen. I have attached a screen shot with the icons highlighted in yellow so you can see what I mean.

James
LL
post #1598 of 2086
[quote=elee532;21844763]Can you give me some idea of how you do this?





I don't know how your receivers (Onkyo) way, but usually there is a switch on the front panel to control speaker A or B or both, off or on. Also there is normally a button on the remote control. The way i do it is turn both off so the only channel is the LFE.
Also i can turn my centre and surrounds off, which is not unusual.

What model is your Onkyo?
You are on the right track bit of fine tuning, take note of James post and post your results back.

There is no need for you to measure anything above 1/12 smoothing.
Omnimic defaults to 1/6 smoothing, and i normally leave it at that, with the odd accasion going higher.
post #1599 of 2086
Quote:
Originally Posted by exojam View Post

elee532,

A few things to suggest for your measurements are:
1) Have your receiver or pre in stereo mode
2) Scale your graphs to either a 5db or 10db size
3) Change smoothing to 1-6th or 1-12th

Thanks James. Here are my next two tries at this. I did turn ON stereo and scaled the graphs to 5db. I forgot to change smoothing from none, but hopefully this still gives a good idea.

Phillips751, I actually have a Denon receiver. Anyway, I unplugged all the speakers execept for the sub. I am thinking this gets the same result that you were suggesting, correct?

The black line is with Audyssey turned off. The red line is with Audyssey turned on. Am I using the OmniMic correctly now? If so, any general thoughts about this reading?

Thank you both!
LL
post #1600 of 2086
elee532,

There you go, looking better. Just to clarify did you have the receiver in stereo mode? I only ask due to this statement "I did turn off stereo".

Now that you are getting the hang of it for your next reading I would look at changing the smoothing to 1-12th and end your graph around 100HZ since you are not getting much past that.

Also, just to give yourself an idea of what happens when you move around in the room. Move the mic to different locations and take a measurement, save it, move to another location, measure, save, etc (do not change the master volume level though). Than you can load the saved frd file(s) and compare different areas of the room and what kind of response you get.

James
post #1601 of 2086
Quote:
Originally Posted by elee532 View Post


Thanks James. Here are my next two tries at this. I did turn off stereo and scaled the graphs to 5db. I forgot to change smoothing from none, but hopefully this still gives a good idea.

Phillips751, I actually have a Denon receiver. Anyway, I unplugged all the speakers execept for the sub. I am thinking this gets the same result that you were suggesting, correct?

The black line is with Audyssey turned off. The red line is with Audyssey turned on. Am I using the OmniMic correctly now? If so, any general thoughts about this reading?

Thank you both!

I would guess your crossover is set at 80 Hz based on the FR. When I measure my subs I set the crossover as high as it goes so I can evaluate the subs entire FR.
post #1602 of 2086
Quote:
Originally Posted by elee532 View Post

Phillips751, I actually have a Denon receiver. Anyway, I unplugged all the speakers execept for the sub. I am thinking this gets the same result that you were suggesting, correct?



Yes you do get the same result but alot easier/quicker to push a button on the reciver or remote.

What is your model Denon?

Have you found speaker A and B?

Using the frequency response tab is great to use for finding the best position for speakers & subs, mainly because it is continous.

A good graph to check bass is in the bass decay tab. I have adjusted my subs using this tool and has made some great improvements.
post #1603 of 2086
Quote:
Originally Posted by exojam View Post

elee532,

There you go, looking better. Just to clarify did you have the receiver in stereo mode? I only ask due to this statement "I did turn off stereo".

Ooops. Yes, that should have read "on." Corrected.

Thank you for the help!!
post #1604 of 2086
Phillips761, Gooddoc, Exojam,

Thank you for the very clear instructions!!

Quote:
Originally Posted by Phillips751 View Post

What is your model Denon?

Denon AVR-990

Quote:
Originally Posted by Phillips751 View Post

Have you found speaker A and B?

I have not, but I'll dig a little deeper into the manual.

Quote:
Originally Posted by Phillips751 View Post

A good graph to check bass is in the bass decay tab. I have adjusted my subs using this tool and has made some great improvements.

I look forward to giving it a try. And, if I can't figure it out, I now know where to come and get a good answer.
post #1605 of 2086
elee532,

No problem with the help, glad you are moving forward.

James
post #1606 of 2086
Has anyone made a comparison with the new hardware mic etc (V1 vs V2)?
post #1607 of 2086
Phillips,

I think I saw that in the last 10 pages. The comment was that it was very slight.

You can more easily find it by going to the parts express website, find forms and drill down from there.
post #1608 of 2086
So if someone likes the ease of hooking up the Omnimic but want the filters through REW, they can pause the frequency screen, save the curve, open it in REW and calculate filters in the regular REW way....., right?
post #1609 of 2086
elee, there is no speaker a/b on the denon that I am aware of. I just simply put the AVR on stereo like you, and unplug the mains, leaving the surrounds in since there is no content being sent to them anyways
post #1610 of 2086
Quote:
Originally Posted by JimP View Post

..open it in REW and calculate filters in the regular REW way....., right?

That is the way I do it to generate filters for my BFD...
post #1611 of 2086
Quote:
Originally Posted by JimP View Post

So if someone likes the ease of hooking up the Omnimic but want the filters through REW, they can pause the frequency screen, save the curve, open it in REW and calculate filters in the regular REW way....., right?


Yep you save as a frd file and import into REW.

You need the impulse to use the Find Resoances/Waterfall features (plus all the mesurements) in REW, which could be very handy especially if you have PEQ. I have tried this saving the Omni Impulse to a WAV file and importing into REW but it doesn't give a accurate result.

I believe that Bill is working on saving the Impulse in the next update, hopefully that will be suitable to import in to REW. If this is able to work it would be fantastic.
post #1612 of 2086
Are there any guidelines for where to set the volume when taking readings with OmniMic?
post #1613 of 2086
~30 dB above your room's noise floor would be good.

Or whatever it takes to get stable response
post #1614 of 2086
elee532,

To expand a little on what Noah is saying (and Noah please correct me if I am wrong).

Before you start taking your measurements, what you can do to check for how much noise is just present, is go into your SPL tab and see what it is showing. I have attached a screen shot of the noise present in my room at the listening position before I started my measurements on 3-26-12.

The other thing I usually try to do but sometimes forget is to run your receivers test tone (for subs) as an example and make sure I get 75db at my listening position. I do this to make sure no changes in my subs trim need changing, which once set should not need to be changed.

One last step I do is to always take measurements with the master volume at the same level. That way I feel confident in comparing measurements from different days, months, etc. If you notice in some of my measurement screen shots they start with _5, that’s my way of noting that the frd save was taken with the master volume at -5.

James
LL
post #1615 of 2086
Noah,

Were you able to get your graphs down to 5HZ?

One thing I have noticed is that even though the frequency response tab will take measurements down to 5HZ now, other sections will not.

As an example even though the SPL readings will allow you to go to 5HZ the measurement itself does not go down that far. I have not had a chance to look at other sections to see if this happens but I hope to do some measuring tomorrow and will look at see how it is working. I believe this is something Bill will need to address.

James
post #1616 of 2086
How would you recommend the process of adjusting a graphic eq?

I want to go back to the drawing board and try something else.

What about the RTA?

Do you measure/eq one speaker at a time (to find the affending channel) then combined or just combined?
post #1617 of 2086
Quote:
Originally Posted by Phillips751 View Post

How would you recommend the process of adjusting a graphic eq?

I want to go back to the drawing board and try something else.

What about the RTA?

Do you measure/eq one speaker at a time (to find the affending channel) then combined or just combined?

Actually, in the strictest sense, a graphic really has no place in home audio. It way too course below the transition frequency. And above the transition, one shouldn't typically EQ. A parametric EQ should be used down low and a combo of acoustic treatments, speaker design and placement should address problems above the transition frequency.

I've got several EQ's,...including 1/3 octave graphic, several parametrics. Parametric EQ's are essential for subwoofer adjustment in HT's.

Good luck
post #1618 of 2086
Quote:
Originally Posted by FOH View Post

Actually, in the strictest sense, a graphic really has no place in home audio. It way too course below the transition frequency. And above the transition, one shouldn't typically EQ. A parametric EQ should be used down low and a combo of acoustic treatments, speaker design and placement should address problems above the transition frequency.

I've got several EQ's,...including 1/3 octave graphic, several parametrics. Parametric EQ's are essential for subwoofer adjustment in HT's.

Good luck


Thanks for that.

It is built into the receiver.

I have attached a graph that has NO eq at all.

The black response is both main speakers playing and the others are seperate (red is left, blue is right).

I have also included indvidual graphs on seperate images (both & left, right).

If anyone can tell there thoughts it would be appreciated.

The sound is absoluteley horrible, extremely dry, drony, honky etc. I wonder if they are out of phase?

Has Bill replied to any questions about the orientation of the mic?
LL
LL
LL
post #1619 of 2086
Quote:
Originally Posted by exojam View Post

To expand a little on what Noah is saying (and Noah please correct me if I am wrong).

Nope, ya done good, James

Hmm, your room is about 10 dB quieter than mine.

Quote:
Originally Posted by exojam View Post

Were you able to get your graphs down to 5HZ?

Just tried (no mike connected) and sure enough, if I just keep clicking the graph expander arrow, it goes down to 5 Hz.
post #1620 of 2086
Does Omnimic have a correction other than the Mic calibration file?
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