Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 376 - AVS Forum
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post #11251 of 11261 Old Yesterday, 03:57 PM
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Originally Posted by HDgaming42 View Post
But where does it lie?

The only thing that agrees with my AVR is this RTA method, which makes no sense as it is using the same tone generator in REW that doesn't agree with my AVR...
A possible answer, based on your earlier frequency response, is the variation in levels across the range. You have 10dB from 45 to 30Hz for example. Perhaps you should eq first and then revisit to avoid chasing ghosts.
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post #11252 of 11261 Old Yesterday, 04:27 PM
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A possible answer, based on your earlier frequency response, is the variation in levels across the range. You have 10dB from 45 to 30Hz for example. Perhaps you should eq first and then revisit to avoid chasing ghosts.
An astute observation. Thank you for taking the time to go back and peruse the mountain of data I've collected to offer this explanation.

Judging by how a non-averaged RTA was entirely unworkable, I suspect, like you're suggesting, the disparities I have in the bottom end are what is responsible for the variation I see between calibration methods.

I will stick with the AVR settings for now and continue down the (long twisting) path toward home theater nirvana.

As for the Mackie monitors, if I never intend on running them at reference levels (the room is a shoe box, and that would likely deafen or kill the occupants) could I get away with simply leaving them at "normal"? From the numbers you (re)provided, this seems reasonable to me...
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post #11253 of 11261 Old Yesterday, 04:54 PM
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I have a question about room treatments. As I mentioned previously, I didn't get around to canceling my order for the mineral wool boards. I have a case of 6 Roxul Rockboard 80, and another case of 6 Roxul Rockboard 60 on their way now. The 80 is 8 lb/ft3 (equivalent to OC 705), and the 60 is 6 lb/ft3 (equivalent to OC 730). I was planning to create two 6" thick bass traps using the Rockboard 80. Do you guys have a recommendation of what I should do with the 60? Should I build 2 less dense bass traps, or should I build some broadband absorbers? If I go for broadband absorbers, should I go for six 2" thick or three 4" thick panels.

Also, the back wall near where the sub is set up rattles quite a bit when things dig really deep (think the skadoosh scene in Kung-Fu Panda). Will placing an absorber back there help with the rattling?
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post #11254 of 11261 Old Yesterday, 07:11 PM
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Originally Posted by 3ll3d00d View Post
FWIW there's some good info on what the levels really should be in this thread - http://yabb.jriver.com/interact/inde...topic=77124.20 - and why narrow band pink noise is a bit of a fudge to allow for deficiencies in the measurement chain. In particular note the comments from bobkatz (aka http://www.digido.com)
Slowly making my way through this thread. What an excellent resource! I can see why Markus advocates the RTA method:

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Im with Bob on the sub/LFE setup. I never ever trust pinknoise and RMS meters for the sub and LFE (even narrow band LFE noise) which is why I use sweeps, and individual tones from 20hz to 200hz with FFT analysis to check for funky cross over problems and room modes before i even think about level matching. Almost all common household rooms will have problem room mode frequencies in the 30-100hz range (standing waves and nulls) which makes RMS pink noise useless because your going to have upto 10db room mode peaks and 10db holes between 20-300hz or so. The meter wont be able to distinguish a room mode peak or a null or a crossover problem. Only careful measurement with proper instruments can properly set LFE/sub crossover and levels if you want the most accurate result.
I believe this addresses my situation exactly. Thanks 3ll3d00d!
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post #11255 of 11261 Old Yesterday, 07:57 PM
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As for the Mackie monitors, if I never intend on running them at reference levels (the room is a shoe box, and that would likely deafen or kill the occupants).
Reference level is reference level. Headphones, shoebox, stadium, doesn't matter. The only difference is the power requirements required to produce that level.
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post #11256 of 11261 Old Yesterday, 11:05 PM
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Reference level is reference level. Headphones, shoebox, stadium, doesn't matter. The only difference is the power requirements required to produce that level.
Unfortunately the perceived loudness of "reference level" is different in different sized rooms. The premise that the steady state response would directly translate to perceived loudness is flawed.

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post #11257 of 11261 Old Yesterday, 11:13 PM
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Does this look (attached) correct? I was able to match up 60Hz, but 30Hz is out of wack...
You just have found out that the room distorts the magnitude response of a speaker by a great deal. Run Audyssey and you'll notice that the response will be much smoother afterwards.

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post #11258 of 11261 Old Yesterday, 11:19 PM
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If the RTA method is bulletproof then great, I guess we're done. I just don't understand why both test tone CDs (two sets of pink noise) and REW both want my sub lower than the AVR and the RTA method...
They average the response of different frequency ranges. Your response is VERY uneven at low frequencies.

If the RTA method shows large deviations between the bands like in your room then you need to optimize speaker setup and room acoustics.

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post #11259 of 11261 Old Yesterday, 11:29 PM
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Originally Posted by Bluescale View Post
I have a question about room treatments. As I mentioned previously, I didn't get around to canceling my order for the mineral wool boards. I have a case of 6 Roxul Rockboard 80, and another case of 6 Roxul Rockboard 60 on their way now. The 80 is 8 lb/ft3 (equivalent to OC 705), and the 60 is 6 lb/ft3 (equivalent to OC 730). I was planning to create two 6" thick bass traps using the Rockboard 80. Do you guys have a recommendation of what I should do with the 60? Should I build 2 less dense bass traps, or should I build some broadband absorbers? If I go for broadband absorbers, should I go for six 2" thick or three 4" thick panels.
Make them as thick and broadband as possible. Reducing low frequency energy from the room will improve the perceived sound quality more than killing first reflections like many recommend. It's harder to do than higher frequency absorption and it's even harder to measure but it reduces deterimental effect caused by upward masking. You'll hear more detail in higer frequencies.

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Also, the back wall near where the sub is set up rattles quite a bit when things dig really deep (think the skadoosh scene in Kung-Fu Panda). Will placing an absorber back there help with the rattling?
Probably not. You'll have to find what is rattling and dampen it.
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post #11260 of 11261 Old Today, 12:09 AM
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Make them as thick and broadband as possible.
For the Rockboard 60, Are two 6" panels better than three 4" panels, even through they cover less surface area in the room?
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post #11261 of 11261 Old Today, 12:12 AM
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^
What's the flow resistivity of Rockboard 60?

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