DIY construction methods of hang-able acoustic panels (not fixed frames) - Page 3

Home Theater Ceiling Acoustic "Cloud" - Part III 1st row


Made the 1st row Acoustic "Cloud", it was finished Thur Feb 24 and installed that evening.
Very similar to the 2nd row with some changes noted below:

Change 1:
I made the end cross braces 23 3/4" instead of 24" like prior, this gave a good "squeeze" grip onto the rigid OC703.
(1st one I only made the inside cross braces smaller)
Really, my wife and I lifted the cloud frame with the OC703 and it was held tightly inside, of course the fabric was securely stapled as prior.


Change 2:
I wanted to only catch the 1st reflections, yet wanted same size as 2nd row for aesticts, so using the mirror on the ceiling (2 person job), the blue tabe shows the boundary for seeing the speakers on each end.
I therefore blocked the mi-hi frequency by using a 12" x 24" piece of kraft paper on the LH side and a 18" x 24" piece of kraft paper on the RH side.
By doing so I still will get the broadband bass effects there w/o over damping the room.


Change 3:
Installed, I added extra chain links into the 8 chains, in future I could lower these 2" or even 4" and add more OC on top for more broadband bass absorption - this is a future option just making easier now by doing this.
Currently I'm 12" below the ceiling with 4" depth of OC703.
By the 1/4 wave guideline I should be using 6" depth currently, I've got 6 sheets of OC703 unused, if I don't use them for some limited rear wall absorber (instead of diffuser since 2nd row is quite close to rear wall) then they will go "in the clouds" ..


I have 2 ideas on the 1st row ceiling lighting, that is side project.

Note:
For my side wall treatments with exposed framing I was really concerned about the fibergalss panels not being "gripped"/held - the young kids issue for me, that is why I went thru all the hassle of the routered center.
Now, with the 1/4" squeeze" seem's that might work as well, and much easier.
Lesson learned for others making side treatment panels with fully exposed frames to consider.
(I did not want to put something like 1/4 round mldg there either to trap the wrapped fiberglass panel, though that is another option)

Actually I just got email Thursday that the 8" x 8" samples from the local guy are ready for my pick-up, but was too busy to stop by last week.
I'll be getting them tonight on way home from work and test them weekend of 3/5, or more likely 3/12 when the other samples from Spoonflower come in for efficiency and comparision will be more apples-apples http://www.avsforum.com/avs-vb/showt...0#post20055530

I picked up the local Acoustic transparent printed image samples, pinned them to the side wall panels, and did some visual comparisons.
(those are my upper corner bass traps done as well, the mounting brackets are being painted/drying now.)

The fine weave is on top, the blocky weave is on bottom:




Fine Weave:


Blocky weave:


Screen light reflection test, 5 sec exposure-side shot


Onlook shot


My visual observations:The fine weave is too flat and does not hold the color pigments as well as the blocky weave.
The block weave appears to be glossy to semi-glossy, the image does show decent, better in person than the picture shows.

Both passed the breath test, Aaron (the local shop manager) told me after printing they pealed the fabric off its backing, and it does appear the majority of the holes before/after is same.
Based on my observation, blockage by this process is a non-issue.

My image for frequency testing is using REW:
-driving thru the Ext In and bypass any in A/V processing of signal
-put one of my main speakers in front/center of room for equal distance from walls (reduce the SBIR as much as possible)
-take near field test with microphone centered on tweeter,
-then with cloth between at 0 degrees, then 15/30/45 degree.
-Repeat centered on midrange.
-Repeat for other sample.
-Compare freq plots.

I'll make a simple test stand out of PVC pipe to hold the samples and easy consistent rotate 15 deg increments.

My fact based data from this past weekend, pictures!
Sorry for rant here, I will email and contact acoustimac directly on this.

The 6 panels taken out of box:


All measured consistent 23 1/8" wide .........................................47 1/8" tall


Having to adjust my cutting tempaltes for slightly different size
(I have a large one I also used not shown here)


Their panels were slightly less than 2" thick also, like 1" and a "fat" 7/8", when stacked gave a different height than using OC705 would.
Here is where I designed these for OC705, already cut the threaded rod, and this was with the OC705 (if used) compressed.
Luckily I had enough material to make 2 more 24x24x34 triangles and added a 13th piece to each to take this gap up.


Note:
The shipping box for the OC703 and OC703 was 13" in depth (outside cardboard dim) from atsacoustics - and they were stuffed tightly in it, the ECOUSTIMAC eco line box was 12.5" deep (outside cardboard dim).

Shipping weight, each 6 panels 2" thick 2' x 4':
From UPS label:
OC703 = 26 lbs
OC705 = 51 lbs
ECOUSTIMAC eco line = 29.2 lbs

I'm hoping the acoustic absorbtion properties of the ECOUSTIMAC eco line are truly what they advertise, I "trust" them, but how to verify?
I don't have that ability.....
I'm feeling slight buyers remorse here guys, I like being "GREEN" and the non-itchy usage, but these little things sorta take the winds slightly outta my "GREEN" sails.

[update]
This issue is closed, see post #76 details http://www.avsforum.com/avs-vb/showt...1#post20087341

I don't know the exact fabric spec (yet), I;ve asked that in email to Aaron.
Plus, I should have use correct printer profiles for my image export.
portion of my email:

On the dipole speaker Q (for front mains), do a search in the master acoustic thread, I've seen that in there multiple times.

I'm not treating the rear/side surround speaker reflections at all, nor sure if I will ......I've seen some people use diffusers for those....I've not studied that far yet....still researching....

I sent them email about 10 minute ago, that is start of dialog and mutual understanding.
Hopefully they give me fact based and logical response.

However, simple mistake, no way!
It is so easy to have a template and Quality Control measures to do this job.
I've audited OE auto suppliers who do this "cotton shoddy" work day in and day out with much closer tolerance control.

All I'm asking for is what I bought, 24" x 48", so design can be done before material arrives. It's not "lumber", where a 2 x 4 is really 1 1/2" x 3 1/2".
They'd get crucified in the HVAC business if some person designed ductwork exactly (24" x 48") and @ the jobsite their material arrived and was 23 1/8" x 47 1/8".

IF their end product is 23 1/8" x 47 1/8" nominal, with 1/8" variation, they should advertise as such, and we could know that upfront and design for it.
That's not asking too much I feel in this day and age of 6 sigma QC/etc.

[update]
This issue is closed, see post #76 details http://www.avsforum.com/avs-vb/showt...1#post20087341

Part II Upper bass traps

Starting from here:

Plan out the cuts to maximize material usage....I had an image on how to do this and just sketched it out like this.
Each sheet I used as fully as possible.


Using newly made templates for the 23 1/8" x 47 1/8" sheets I have, start cutting and stacking, cut in reverse order, ie, the big one first and smallest last.
This is big template........................Smallest template showing placement


This cotton product is much harder to cut thru than OC703/705, so I bring out the turkey knife. Still cuts came out not nicely, determined my blades were dull and sharpened them , much better after sharp blades.



2 traps cut and stacked! I will use those "extra" pieces shown, part of my material usage plan.


I was not 100% satisfied with how the lower corner bass traps edges looked, so decided to tryout using drywall edging. I picked the white paper covered ones to minimize any issue with shiny reflection being seen thru the fabric. If need be, I would have painted them green, but that was not needed.


I used fishing line to secure the the bottom side and screws the top side.

Part III Upper bass traps

1 done with material stacking, added loose pieces with sticky spray, worked great.


Putting on the Kraft paper to block mid-hi frequencies:


1st one wrapped and done!
Those drywall edges made all the difference, I'm going to add those as lesson learned to lower bass trap post. Much crisper look.




Installing into the HT room.
I used a 30+ year old hydraulic bottle jack as 3rd hand...


Both installed


Detail LH side....................................RH side


That completes the Rear wall broadband bass treatments.

side note:
I've used that exact same red hydraulic bottle jack back in the late 1970's when I had my 1969 Ford Torino with 390FE engine with 427 med-riser race parts, I was a car jock back then & re-built my engine 3 times...blew up 2 engines before 18 years old.
It was good to help lift up stuff (trans/whatever) to align during engine "re-entry" back into the car.
This is 1979, I'm the guy with blue coveralls on leaning on the engine cherry picker.
Yes, I had a 2 x 4 "Dual Quad" set-up as well in my 11th grade high school, can we say 400+ REAL horsepower and leaded gasoline.

I got a phone call directly from Sal, he also sent this email:

They have 2 different size, the one I was shipped 23 1/8 x 47 1/8 is for their pre-made frames so the outside dimension to customer is 24" x 48".
I was wrongly shipped those, they do have full 24" x 48" stock as well.

Sal offered for me to ship back my stuff for free exchange (too late, already done), or some other $$ (partial refund or good discount on next buy).

I have to assess my future needs and decide which route I'll go, I'm ok with their response and he truly wants to keep the customer happy and admitted it as their mistake.

Case closed.

Thx guys! It feels good to have those done and turning out decently, I was worried with them hanging up high if they looked so-so what people would say...
And scl23enn4m3 I agree, having a shelf is functional and the 2 traps helps keep the room "openness feeling" decent along the rear wall.

PTAaron - I posted this in another thread;

That is my subjective ranking, this weekend I'll get REW hooked up and take objective measurements and post those as well, for fact based data/graphs correlation to the subjective rankings.

In response to a PM:
The upper bass traps are just sitting on (2) L brackets each, gotten from Lowes in the outside deck building area, painted them green.
By simple geometry they are trapped up there, not even attached screws to lower wood piece.
I did put 3/4" round felt on the top/ceiling piece to space it off the ceiling and ensure no vibrations.
Also on the wood edge to space it off the back/side walls, no issue with vibrations at all.


Other:
I did not take REW frequency readings this weekend for the bass improvements.
My AT picture samples for the side wall treatments from "spoonflower" are due later this week, therefore I will tackle that project (which supplier to work with on AT picture fabric) with the improved Bass readings at same time.
(it's a lot of cables/etc getting REW up and running......)

Got the samples in from Spoonflower last night, simply I was blown away by the picture quality!

Same test as before, I added the Spoonflower to the bottom, also a few from ats acoustics as comparison.

I did the breath test, comparing the Spoonflower material vs the ats acoustic sample pack I have http://www.atsacoustics.com/item--St...ack--1034.html

Subjective rating via breath test:
1) Spoonflower fabric passed more air than the ats acoustic sample I had for the microsuede
2) Spoonflower fabric passed same air - or slightly easier - as the ats acoustic sample cotton weave sample
3) The ats acoustic burlap definitely passed the breath test the most.

Picture quality comparison:
(these are all my original photos, so I can compare them)

This is w/o flash with HT lights on about 50%:


Pict with flash (white balance set according for each shot):


These close ups are all straight from my T1i camera, RAW format w/o any post processing added.
#1 ; the detail in the craters is fantastic, nearly same as original


#2 ; this racoon fine fur detail again quite good


#3 ; the star trails kept streaks and the star colors


#4 ; this B-17 shot in B&W was to see how it fared for B&W....really good


#5a ; tree @ night via spoonflower


#5b tree @ night (blocky weave from local supplier)


#6 reflection test - passed with flying colors!
The cotton weave has less sheen.


Ding - ding - ding: we have a clear winner! Spoonflower .
(Thx luma for pointing them out)

Very impressed with the picture quality, color matching seems spot on, much detail is there, only the star field with the 5 meteorites proved too much for their process to reproduce.

I will take objective freq comparisions later, however I see absolutely no reason not to recommend the spoonflower fabric and process for anyone looking to have Acoustic transparent artwork for their acoustic treatment panel covers.

[edit 3-9-2011: use their Quilting Weight Cotton, http://www.spoonflower.com/spoonflower_fabrics]

After doing the subjective "breath test" of various fabrics for the AT-ness (Acoustic Transparency ability), I did want to do some objective testing to get a feel for the AT-ness frequency wise of the various fabrics I've been considering for the art coverings on the wall treatments - and share with others.

This past Saturday I built a $20 test fixture out of 1 1/2" PVC pipe, used a closet flange to bolt it to leftover 3/4" OSB 19" x 19" board.
The "T" tee fitting is NOT glued to the 24" upright for easy rotation to simulate various angles of interaction like in real life off side walls / ceiling.

Quick and easy, and holds the test sample via tape.

The test zone is 16" x 16" so I can read the midrange and tweeter drivers separately by adjustment of the mic boom stand.
My Paradigm Monitor 9 midrange driver is 32.0" above base and tweeter driver is 37.25" above base.
I marked the baseboard every 15 degrees 0-15-30-45-60.
(but did not take measurements @ 15 or 30 deg)

The fixture is set to be 4.25 inches from the cone center, and the measurement mic is 0.75 behind the fabric being measured.

If I made the fixture closer to the speaker then I could only rotate it to 30 deg before it hit the speaker sides.
I realized not perfect "nearfield", but my goal here is to quantify the change in frequency amplitude being passed thru the various fabric's to compare the subjective breath test with objective AT data.
(and learn by doing)

As used in the HT, my RH/LH main speakers are 24" from side wall and 28" from back wall, toed inward slightly.
For this Sunday afternoon quick round of testing I did NOT put them more centered in the room.....
I had about 90 minutes to do all this in the basement while my 2 boys (7 and 5) were in the 2nd floor loft playing games, so had to work quickly.
(with HVAC/other off to lower the sound floor)

Here it is at 0 degrees measure (simulating direct reflection @ 0 deg)....Here it is at 45 degrees measure (simulating reflection @ 45 deg)


Here is the fabric from spoonflower being measured.
All measurement were done with REW5 driving thru the Ext-IN, bypassing any processing.
(cables and "stuff" everywhere)


Side view of set-up.........front 3/4 view of set-up


I took over 30 measurements via REW5, iMac 24", Behringer ECM8000, and will group them into logical parings for comparison purposes and review.
-Baseline of Midrange and tweeter w/o any fabric
-Midrange and tweeter thru spoonflower fabric @ 0,45,60 degrees
-Midrange and tweeter thru local supplier blocky fabric @ 0,45,60 degrees
-Midrange and tweeter thru kraft paper @ 0,45,60 degrees
-Midrange and tweeter thru 3/4" pink hard insulation board @ 0,45,60 degrees (for comparison to kraft paper for blocking mid-hi freq in bass traps)

Again, the fixture is set to be 4.25 inches from the cone centers, and the measurement mic is 0.75 behind the fabric being measured. Not perfect nearfield but close for this purpose.

I'll post those graphs later with my comments for discussion.

I understand your Q - if AT movie screen material is great for the projected light visual AND is AT, why not use that for printed coverings on rear surrounds (and possible fabric covers for acoustic treatments I'll add).

I'm simply not sure the printing process used by the online place spoonflower.com or the local place (used a HP 9000 series Designjet that is fed by material on a std size roll ) could do that.
Each uses equipment with its own set-up parameters.

Can you follow-up with an inquiry to the supplier who sell's AT movie screen material with your Q?
Can it be "printed on"? Has it been done before?
What size roll does their material come on? etc.

I'd be interested that result as well.

Set-up:
REW5, iMac 24", Behringer ECM8000, test date March 13, 2011
The fixture is set to be 4.25 inches from the cone centers, and the measurement mic is 0.75 behind the fabric being measured.
As used in the HT, my RH/LH main speakers are 24" from side wall and 28" from back wall, toed inward slightly.

I measured the midrange @ its center height position (32.0")and tweeter @ its center height position (37.25")
Did the 75db calibration @ midrange position and did not re-calibrate for tweeter position.
Applied 1/3 octave smoothing for all these, if subwoofer then I would have applied 1/12 octave smoothing.

paradigm monitor 9 Crossovers specs:
3rd-order electro-acoustic at 1.9 kHz
2nd-order electro-acoustic at 500 Hz


They graphed like this as baseline w/o any thing between them and the mic:
(Blue is midrange, purple is tweeter)
Chart 1 Baseline chart:


Note:
1) I always show the "baseline" midrange/tweeter curve for visual compaision on respective charts.
2) I always ran the measurement 80hz - 20khz, and plotted that way also.
3) When looking at the charts, the midrange you should look at the 500-1.9k freq zone, the tweeter the 1.9k and above freq zone

Spoonflower cotton cloth charts
Chart 2a Midrange with spoonflower cotton cloth, baseline and @ 0, 45, 60 degrees


Chart 2b Tweeter with spoonflower cotton cloth, baseline and @ 0, 45, 60 degrees


>>My conclusion from the midrange/tweeter charts: spoonflower cotton cloth is AT and good to go for acoustic absorber panels usage.

Charts showing mi-hi freq blockage:
Chart 3a Midrange with kraft paper, baseline and @ 0, 45, 60 degrees


Chart 3b Tweeter with kraft paper, baseline and @ 0, 45, 60 degrees


>>My conclusion from the midrange/tweeter charts: Clearly krafty paper does block significant hi freq, it appears not as good at mid-freq blockage

This show the "freq blockage" of kraft paper vs 3/4" pink foamboard:
Chart 4


>>My conclusion from the midrange: Clearly 3/4" pink foamboard does block significant mid and hi freq compared to the kraft paper
(I forgot to do same test for tweeter kraft vs 3/4" pink foamboard, maybe on Part III will do)

This shows a comparision of tweeter for baseline, spoonflower, and kraft @ 0 deg
Chart 5


This shows a comparision of midrange for baseline, spoonflower, and kraft @ 0 deg
Chart 6



I might re-do these as Part III with the speakers more mid room to more remove any wall interaction from these readings, but my quick experience gained is these fabrics seem more AT than I had guessed they would. But, this is my 1st time doing this so no real frame of reference.
I've not come across anyone else here @ AVS doing these, could be burried in the 200+ page Master Acoustics thread, that thread would be so much more useful if an index was at the beginning...There is great info burried in it, lost, and then re-talked about again. I truly feel for Dennis/Ethan/Terry/Ted/Others for answering q's multiple times.

Spoke with "Sal" @ acoustimac,http://www.acoustimac.com/index.php/...5/category/10/ .
I just ordered (3) more cases of their "ECOUSTIMAC Eco Friendly DIY Insulation (4 lbs/ft) 48"x24"x2" -Case of 6 ", guaranteed by Sal to be 24" x 48".
He gave me discount price on the 1st case due to prior situtation.
If I get these Friday 3/18 weekend project will be doing the Front Wall Broadband Bass Traps.
The front LH Corner will get a full floor-ceiling 24"x24"x34" superchunk, while on RH side due to IB sub I'll handle the top tri-corner only.
I've been trying to make all the acoustic treatments non-fixed, however for a whole floor-ceiling bass trap looks like a fixed one is best design.
The front RH top tri-corner will be similiar to the Rear upper bass traps I've made earlier.