Was this thread killed, or did it die of natural causes?
Like many acoustic threads here it took left turns, right turns, and U turns
Last month I added this in post#1, I don't feel this thread has run its full course of usefullness - yet.
[edit Feb-28-2012] Plan to re-boot this thread March/April 2012:
Come spring, when I re-do my 130" screen due to humidity induced warping of the screen, , I will totally remove all my existing side wall/ceiling panels and start from baseline of no treatments on the room
(besides my corner superchunks, which all have front facing reflective treatment on them)
I also will do the following:
-Pure reflective room baseline
-baseline of "the mirror tricK", as I did, with side wall 2" panels + 2" air gap
-Pure ETC approach and using 4" panels + 4" air gap at specific locations verified by ETC
-compare and make objective and subjective assessment
All above is being done utilizing porous absorbers.
As to dragonfyr's editing/removing his comments in specific posts for whatever reason....not sure if that happened or not.
so, with the band-limited ETC, you've not only produced more reflections, but they've also magically increased in gain as well ??
Originally Posted by Nyal Mellor
Like I said previously and as you are no doubt aware an ETC (like an impulse response) is dominated by the highest frequency components. What gives you the idea that you would be able to compare an unfiltered ETC to a set of filtered ETCs?
Although this is referring to loudspeaker design it shows that there are multiple ways to analyze the energy decay - impulse response, ETC, filtered ETC, cumulative spectral decay. All have their place http://www.linkwitzlab.com/frontiers_2.htm
No, it's just an unfiltered ETC is dominated by the highest frequency components.
When comparing the full band ETC to separate bands of 500hz, 1K, 2K and 4K, the full band looks a lot like 4K plot to my eyes. To say the full band ETC favors the high stuff is an understatement I think.
Just read this whole thread , lots of good info but I still don't understand how to read the ETC results . All I see are squiggly lines . Someone should make a video on how to take measurements , how to understand those measurements , and how to apply acoustic treatments for those measurements.