I'm back but confused, again! - Page 18 - Home Theater Forum and Systems - HomeTheaterShack.com

Old 04-23-12, 09:07 AM Thread Starter
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Greg

Join Date: Nov 2006
Location: Omaha, NE
Posts: 205
Re: I'm back but confused, again!

In terms of spectral decay, the way I am interpreting this target value, that I referenced this post:

Quote:
Spectral decay: Decay rate of 20 dB in the first 150 ms from 40 – 300 Hz. (Note: The time window setting for any waterfall or decay plot used to determine this must be set to 300 ms.)
My guess is that I can extrapolate that target range to be 40 dB in the first 300 ms from 40 - 300 Hz. I only included the plots out to 200 Hz this time, so I'll have to take a look later today on the 300 to 400 Hz range. But looking at the spectro graph, it looks pretty good in that regard. The obvious issue is below 40 Hz, right? Just making sure I understand the targets.
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Old 04-23-12, 09:43 AM
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Floyd

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Re: I'm back but confused, again!

Your extrapolation is pretty accurate based on this paper: http://blog.acousticfrontiers.com/st...ist.%20Rms.pdf

o Resonances from 35Hz300Hz
should not extend beyond 350ms before decaying
into the noise floor or reaching a level of 40dB.
o Below 35Hz this standard is relaxed to 450ms
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Old 04-23-12, 10:48 AM Thread Starter
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Greg

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Re: I'm back but confused, again!

Oh, that gives me an extra 50 ms to get down to -40dB. I'm feeling pretty good about my measurements, in terms of decay, anyway. Looks like I'm just outside of the target for the less than 35 Hz.

Thanks for the reference. I believe that's also the one that Earl provided for me earlier, http://www.hometheatershack.com/foru...tml#post513221 and it helps me to identify the targets.

Also, I noticed that the hdacoustics paper you cited shows a sloping line (dashed being the ideal) between the values.

Last edited by angryht; 04-23-12 at 11:01 AM.
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Old 04-23-12, 11:02 AM Thread Starter
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Greg

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Re: I'm back but confused, again!

Here's the figure:

Last edited by angryht; 04-23-12 at 02:35 PM.
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Old 04-25-12, 11:08 AM Thread Starter
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Greg

Join Date: Nov 2006
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Re: I'm back but confused, again!

So, at this point anyway, there's not much more I can do about decay time. Currently, I have several triangular pieces of 1-inch Linacoustic RC (leftover from covering most of the walls) placed at the corners where the wall meets the floor. I think that has helped me to get the decay time reduced. It's probably not as effective as other types of traps, but it's something.

Here are some pictures to show what I mean.

Up next I hope to address some of the dips (nulls) in the SPL responses.
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Old 05-03-12, 07:08 PM
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Re: I'm back but confused, again!

Hi Angry and his consultants ;-)

Just letting you know this is a VERY helpful thread for others to follow along on. Looks like Angry is dealing with most of the possible issues/solutions (software, equipment and room) and reporting well, so the rest of us can get up to speed faster.

Thanks for being the Guinea Pig!

--Caleb
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Old 05-04-12, 07:42 AM Thread Starter
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Greg

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Re: I'm back but confused, again!

^No problem, Caleb, and I am thrilled to hear if anyone has gained any knowledge through my experience. To me, that's the point of this forum. I intend to continue my quest to, as Earl so eloquently wrote earlier, improve the sonic resolution of my listening experience. . . .from earlier:
Quote:
EarlK wrote: View Post
> If you want to improve the sonic resolution of your listening experience, then that is an entirely different kettle of fish ( requiring much much more than REW & a BFD ). The simple way to that experience is to listen to some good headphones .
He was playing with the words in my earlier posts (resolution having different meanings) but I gotta say, that's audio forum gold! Of course the headphones idea is always a good one, I'm sure my wife would agree to that!

I should be able to post more in the next day or so. I did some more measuring at different listening positions which helped some of the dips in the SPL responses. More on that a bit later.
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Old 05-04-12, 08:04 AM
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Re: I'm back but confused, again!

Thanks

..not sure I understand Earl's reply and your reference to Audio forum gold...seems if the goal is to "improve the sonic resolution of your listening experience" that's just what REW can help do...if you want that it in more than a single pin-point location, THAT would be the "entirely different kettle of fish". Maybe his reference was more metaphisical than my literal interpretation

Anyway, yes, I look forward to hearing your next chapters. I am preparing to write up my own guide/walk-through/help request based on REW with JRiver Media Center convolution relating to my 2.2 system in a bad room. After the REW/JRMC baseline, I hope to delve into correction solutions, including: REW / Audiolense / Acourate / DRC comparisons, pros, cons. Time will tell if I can cover all of that. I will certainly reference this/your thread for anyone wanting another great walk-through. We all struggle with the same issues, but have different environments/set-ups, goals and solution-paths. Thanks again for yours and to those who helped you (all of us) learn more.

--Caleb
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Old 05-04-12, 08:22 AM Thread Starter
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Greg

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Posts: 205
Re: I'm back but confused, again!

Quote:
ccclapp wrote: View Post
..not sure I understand Earl's reply and your reference to Audio forum gold...seems if the goal is to "improve the sonic resolution of your listening experience" that's just what REW can help do...if you want that it in more than a single pin-point location, THAT would be the "entirely different kettle of fish". Maybe his reference was more metaphisical than my literal interpretation
I just liked that way he took my use of resolution and flipped it to the audio resolution. I appreciated that.

Quote:
Anyway, yes, I look forward to hearing your next chapters. I am preparing to write up my own guide/walk-through/help request based on REW with JRiver Media Center convolution relating to my 2.2 system in a bad room. After the REW/JRMC baseline, I hope to delve into correction solutions, including: REW / Audiolense / Acourate / DRC comparisons, pros, cons. Time will tell if I can cover all of that. I will certainly reference this/your thread for anyone wanting another great walk-through. We all struggle with the same issues, but have different environments/set-ups, goals and solution-paths. Thanks again for yours and to those who helped you (all of us) learn more.
Sounds like fun. I'm not familiar with JRiver so I'll keep an eye out! Thanks again for touching base!
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Old 05-08-12, 08:11 AM Thread Starter
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Greg

Join Date: Nov 2006
Location: Omaha, NE
Posts: 205
Re: I'm back but confused, again!

Here are some measurements done to determine if I should move my seating related to the SPL graphs (Frequency Response from this earlier post). Position #1 is my current seating location and position #2 is moved forward about 1.5 FT.

This first graph is showing the comparison between the left and right speakers (together), position 1 and 2. Blue is position 2 (about 1.5' forward).

This second graph shows the comparison with the center speaker. Purple is position 2.

To me it looks like I'm getting a better response (smoother) through the 100+ to ~250 Hz range. The center speaker response merely shifted the dip to around 330 Hz. There are a couple of questions that I have related to these:
1. Would it be worth moving the seating position?
2. Should I apply a smoothing to the graphs? If so, which smoothing? I've seen a few posts that indicate 1/24 smoothing and the reference posted (to hifizine.com article discusses 1/3 smoothing).
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