First, Happy New Years!
Measurements - it did happen!
All below are just my IB sub via Ext In w/o any EQ at all, just to see room response.
(I did also take some IB + Mains, which are set at 80hz xover for mains and 120hz as LPF for the IB, those are not posted below, TMI for this post purpose)
Here is base with the "free" above screen traps w/o pink fluffy, this Dec 17th
I took measurements, then added pink fluffy to the void, Dec 27
As stated, the freq response did not improve at all, just the modal ringing slightly, very slightly....most of my LFE is around 300ms, so actually pretty decent
July 1, no trap above screen (saved these from earlier)
Dec-27 trap added above screen without and with pink fluffy freq chart, slightly better at 155hz (which I'm not looking here due to the mains will change that portion)
Dec-27 trap added above screen without and with pink fluffy H20 chart
what I did also find is for my 1st row very dependent on where I put the mic in height position. ie, seat up ear height vs seat down ear height.
2nd row is negligible for height mode change.
Seats 5- 8 all have almost the below response.
1) I'm "done" with adding/tweaking broadband bass porous absorbers in my HT room, overall quite happy - and my wife told me "time to enjoy it!", she's right
2) 2nd row definitely has much smoother bass response, and a nice "house curve"
3) 1st row, if I want to improve the pesky nulls between 30-50hz will need a more advanced strategy, possible membrane absorbers, tbd at this time.
That will be HT acoustics version 1.5 task after more reading/research here and gearslutz, along with some old fashioned book reading.
4) It is important to take LFE readings at the seat up and seat down position (mine are almost 18" different), as well as side-side positions in the seat to grasp each seats response and your strategy.
Also, play sine wave at your trouble nulls and use RS SPL to hear and measure the diff as you go up/down, side/side, and fore/aft to get a understanding of the wave mechanics at play.
That gives intuitive feeling for the issue(s) instead of just graphs/chart/numbers.
5) I'm really curious when I add the double french doors to the HT, and close off the 6' wide opening (huge bass trap now), how the modes will change, and while not obvious now the bass trap above the screen may come into play more then......Summer 2012 thing
6) Knowing now that I got actual almost "nothing" from doing this, would I have done it anyway back then.....possibly I'd wait till the double french doors were installed and see if they caused major null issues.
But, doing this also increased my knowledge of my specific room "issues", so as a hobby part of the learning and tweaking.
7) It's been said before, but I'll repeat:
Label all your measurements immediately!
Taking so many you quickly get lost in them, even when being systematic about the order, if you take 2-3 then you may mis-label one when trying to do in bulk.
This thread has almost reached its conclusion.
I'll add a re-cap to post #1, with some links to portions in the thread for ease of finding stuff.
One thing, when I started about 1 year ago, using pink fluffy for broadband bass super chunks was not widely know here @ AVS, that seemed to be led by gearslutz forum.
For sake of best practices and best cost approach solution, the approach for members in the future should take that into account, and be summarized with the appropriate calculators (localhost127 may have a summary in a post, I'll find that and link it )