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post #1 of 19 Old 01-12-13, 05:14 PM Thread Starter
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Any comments on my measurements

Good Evening,

I'm new to the forum and recently purchased a UMIK-1. I took a few measurements and adjusted basic EQ, crossover, and phase (sub). I was hoping you all would be kind enough to have a look at my measurements and let me know if you see any major problems.

You can have a peak at my theater and equipment list here:
http://www.hometheatershack.com/foru...#axzz2HncYYYFm

Thank you very much for any guidance.
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post #2 of 19 Old 01-12-13, 05:52 PM
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Re: Any comments on my measurements

Looks really good. Do you have room treatments in there?

Hug your pet today!
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post #3 of 19 Old 01-12-13, 05:55 PM
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Re: Any comments on my measurements

I would be more interested to see the un-smoothed or smoothed only 48 material rather than 1/3. Also just low end 10- 400 or so un-smoothed to check any peaks nulls
thanks
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post #4 of 19 Old 01-12-13, 05:56 PM Thread Starter
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Yes I have room treatments. 17 2'x2' 2" Wedge Foam and 2 16x24 super chunks.
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post #5 of 19 Old 01-12-13, 07:36 PM Thread Starter
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Re: Any comments on my measurements

Quote:
brad wrote: View Post
I would be more interested to see the un-smoothed or smoothed only 48 material rather than 1/3. Also just low end 10- 400 or so un-smoothed to check any peaks nulls
thanks
Here's the good, bad and ugly. Brad, hopefully this shed some light.

The first one is 1/48 smoothing as suggested. The last two are no smoothing as requested.

Thanks for the feedback thus far.
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Any comments on my measurements-48-smooth-full-range.jpg  

Any comments on my measurements-full-range-waterfall.jpg  

Any comments on my measurements-no-smoothing-10-400.jpg  

Any comments on my measurements-no-smoothing-20-200.jpg  

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post #6 of 19 Old 01-12-13, 10:26 PM
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Re: Any comments on my measurements

Ahhhhh.. the nasty peaks and nulls are now exposed for what they are...

The room looks great architecturally, but I would comment, after hanging-out in this forum and over at gearsluts for the past 6 months, you should try to look at the following:

1) I'm no expert, but try to get the attention of Bryan from GIK (and visit their site) and also Realtraps Ethan Winer, as THEY are experts and also hjones4841 can give more insight (and there's quite a few more experts on here) both GIK and Realtraps sites, have a lot of info about how to tame your room... I read most of the 38 pages in this forum to better educate myself, as well as that "Master Handbook of Acoustics" by Everest.

2) I would think the placement of the subs in the room is doing something as they look real close to the wall, also I don't see much broadband bass trapping going-on. You should post the dimensions of your room, so mathematically, you can figure-out the room modes and then match that with your measurements. They will tell you to use absorbing stuff in the corners, for sure (which it looks like you have in the front, but not the rear).

3) I had good luck by using REW to generate a sine wave at the particular frequencies that I had either peaks or nulls and then put my ears around in the room and hear the actual drop-outs or increases in amplitude for the given frequency.

4) What does the waterfall look like when you change it to 300 or 400 ms? I feel you should see more ringing and see the noise floor better, that would help to figure-it out.

5) I'm not sure about everyone else, but I'm in the camp that recommends no EQ until the room is the best you can get it acoustically, so I would measure without eq, then start with speaker placement, then low crossover frequency adjustments and maybe broadband absorbing panels, like your super chunks.
Oh, did I mention broadband absorbing panels?? It is not the same as the foam stuff.

Remember to measure each time you change something, so you can track what your results are, and only change 1 thing at a time.

my 5cents
looks good, though
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post #7 of 19 Old 01-13-13, 07:57 AM Thread Starter
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Re: Any comments on my measurements

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2) I would think the placement of the subs in the room is doing something as they look real close to the wall, also I don't see much broadband bass trapping going-on. You should post the dimensions of your room, so mathematically, you can figure-out the room modes and then match that with your measurements. They will tell you to use absorbing stuff in the corners, for sure (which it looks like you have in the front, but not the rear).
Here are my dimensions. 255" x 206" x 104"
Unfortunately the width and height are practically double one another.
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post #8 of 19 Old 01-13-13, 10:07 AM
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Re: Any comments on my measurements

1) Are you measuring one channel at a time for your measurements?

2) 2" thick wedgefoam unfortunately isnt broadband. I would move towards 4" OC703 with 4" gaps or 12" pink fluffy for 1st reflections points.

3) Your frequency response comes out to about +/- 11db. This needs to be improved. Shoot for +/-5db or so. More bass traps and thicker better 1st reflection attenuation should help things in this regard.

4) Your waterfalls look pretty good until you get to 40hz. Those too will improve with more bass trapping.

5) Recommend a ETC response. It will tell you important things about your room that FR and Waterfalls cant.
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post #9 of 19 Old 01-13-13, 05:03 PM Thread Starter
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Quote:
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1) Are you measuring one channel at a time for your measurements?
I am typically using the front left and subs.

Quote:
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2) 2" thick wedgefoam unfortunately isnt broadband. I would move towards 4" OC703 with 4" gaps or 12" pink fluffy for 1st reflections points.
I believe the foam is good to about 500Hz. I plan to add additional bass traps, but have no plans to replace the foam. Unfortunately the rear wall-wall corners are not suitable due to the entry door and equipment rack. All of the ceiling-wall corners are on the table for discussion. I have a good local source for mineral wool and would be willing to do super chunks around most of the ceiling-wall corners if you think it's needed. I am quite pleased with things since I've added the super chunks, but am of course looking to improve or I wouldn't be here!

Quote:
jim1961 wrote: View Post
3) Your frequency response comes out to about +/- 11db. This needs to be improved. Shoot for +/-5db or so. More bass traps and thicker better 1st reflection attenuation should help things in this regard.
The measurements shown are the result of Audyssey MultiEQ XT after being measured in 6 positions. I "can" flatten this one microphone position manually by sacrificing others, but have chosen not to at this point. Is it worthwhile to take measurements without EQ while trying to asses the room? Since I have an AT Screen I am considering taking some near field measurements to compensate for the screen with manual EQ and then have a better ability to work on the room. Is there merit in this?

Quote:
jim1961 wrote: View Post
4) Your waterfalls look pretty good until you get to 40hz. Those too will improve with more bass trapping

5) Recommend a ETC response. It will tell you important things about your room that FR and Waterfalls cant.
Can you really effect 40Hz with a 24x24" corner bass trap?
I'll do some reading on ETC (energy time curve?) response this evening.

A big thanks for all your help!
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post #10 of 19 Old 01-13-13, 05:39 PM
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Re: Any comments on my measurements

Quote:
eclipse911t wrote: View Post
I am typically using the front left and subs.



I believe the foam is good to about 500Hz. I plan to add additional bass traps, but have no plans to replace the foam. Unfortunately the rear wall-wall corners are not suitable due to the entry door and equipment rack. All of the ceiling-wall corners are on the table for discussion. I have a good local source for mineral wool and would be willing to do super chunks around most of the ceiling-wall corners if you think it's needed. I am quite pleased with things since I've added the super chunks, but am of course looking to improve or I wouldn't be here!
2" wedge foams affects frequencies down to 500hz, but only evenly down to 800hz -1k.

Edit: http://www.auralex.com/testdata/test/2wedge.pdf

Reading the above link, you might be led to believe its good to about 500hz. But read more carefully, and the test size they used was 96" x 108", not 24"x 24". Big difference.



Quote:
eclipse911t wrote: View Post
The measurements shown are the result of Audyssey MultiEQ XT after being measured in 6 positions. I "can" flatten this one microphone position manually by sacrificing others, but have chosen not to at this point. Is it worthwhile to take measurements without EQ while trying to asses the room? Since I have an AT Screen I am considering taking some near field measurements to compensate for the screen with manual EQ and then have a better ability to work on the room. Is there merit in this?
I would measure without EQ, otherwise you dont really know what the room itself is doing. The better you can tame the room, the less hard Audyssey has to work. Ideally, one could get the room right enough and not need Audyssey at all. Measurements taken at where you will be listening will be the most relevant.


Quote:
eclipse911t wrote: View Post
Can you really effect 40Hz with a 24x24" corner bass trap?
I'll do some reading on ETC (energy time curve?) response this evening.

A big thanks for all your help!
More trapping may not solve <40hz problems, but it may help them some. Doubling up 2 24x24 to make a 24x48 or even a 24x72 would help more. Energy Time Curve, yes. Sometimes also call Envelope Time Curve.

Last edited by jim1961; 01-14-13 at 11:12 AM.
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