a LAZY MAN's "SUPERCHUNKS", packs of [ROXUL RHT40] or [PAROC NRS 2t] in corners

[danielveres]

I need broadband absorbers for my controlrooms and I'm too lazy to build a set of wedgeshaped-Superchunks, so I decided to reserach my options, and this is what i've come up with so far:

In each corner I will put two "wrapped/UNOPENED" square shaped packs of [PAROC NRS 2t] one on top of the other, thus covering the corner from floor to ceiling. Then maybe just hang some type of fabric over it for looks.

Each pack measures 47.2 * 23.6 * 15.7 inches (1200*600*400mm) [containing four 100mm thick slabs]

Density of [PAROC NRS 2t] is 4pcf (65kg/m3)
Density of [ROXUL RHT® 40 Industrial Board] is 4pcf (65kg/m3), they seem to be very similar product.

$440 USD buys me 91.5 cubic feet, weight 370 lbs (2.6 cubic meters, weight 168kg) of [PAROC NRS 2t]
(comes packaged in 9 packs of the dimensions mentioned earlier.)

This way I won't have to worry about minrealwool-fibres fying aroundin the room, plus I won't have to spend any time building anything.
I plan to place the packs right in the corners, not stradling.


Will the fact that I don't remove the plastic wrapping noticeably affect absorption in frequencies below 400hz?
(I double-checked so that the materials are NOT compressed by wrapping to save space during storage/transport, as is the case with some product of lighter density)

As I am covering rougly 1.28 times the space in the corner compared to a 34"-face superchunk of the same height [2.56 times the space of a 24"-face superchunk], I'm expecting similar absorption performance to that of a 34"-face superchunk.

Any thoughts or advice ? Am I overlooking/missing something?



Footnotes:

I will place a couple of 6ft high 2" thick GOBOs (framed+clothed rigid fiberglass) along the side walls, and perhaps backwall to deal with reflections in midrange and upward.
There is a window in the front wall, right now the speakers [Genelec 1030am] are placed against the front wall on each side of the window, leaving about 19 inches on the sides to stick my PAROC/ROXUL

If this works out well I will probably end up using it in several rooms, but I'm starting with the room where plan to do most my of mixing.

for those curious about the dimension of the room in question:
2.57m high
4.18m long
2.99m wide

[gullfo]

the plastic should be OK to leave on. i did this design for someone who needed something similar.

[danielveres]

Thanks for chiming in Gullfo.. anyone else has any thoughts?

Ordered the materials today, so it should be with me within two weeks.. can't wait

Decided I will try the materials in both my rooms at my main mixlocation and select the one that ends up better sounding, hoping for the bigger room.

Smaller room: (3 corners possible)
2.57m high
4.18m long
2.99m wide (window in center front wall, doorway on right side in backwall)

Bigger room: (all 4 corners possible )
2.57m high
4.48m long (doorway center-left, window [covered by semi-thick curtain] center-right)
4.02m wide (sofa against back wall, 2" glassfiber on whole front wall)

[Glenn Kuras]

Actually that will work pretty well.

Glenn

[Hannes_F]

Which flow resisitivity does your material have?

Porous Absorber Calculator is your friend. ZORBA can even calculate the influence of the plastic.

This geometry will help to reduce the reverb time. Not necessarily the cancellation dips in your frequency response.

[danielveres]

Glenn: Thanks for the input.

Hannes_F: Thanks, I will have to check out Zorba, I tried Porous Absorber Calculator V1.52, but I couldn't figure out the Airflow Resistivity (Rayls?) of [PAROC NRS 2t] 4pcf (65kg/m3) , neither that of [ROXUL RHT40], perhaps you can shine a light on those numbers ? The data i found on their respective webpages didn't make me any wizer.

I re-read THIS (1) thread, and THIS (2), realized both seem to be dealing with rooms of similar dimensions as mine. A very informative read.

If I don't get an even enough response down to about 40Hz after stacking [PAROC NRS 2t] in all four corners I will try a different approach for the backwall by moving the materials from the backcorners to the center of the backwall to form a centered-backwall-absorber 16" deep, 4 feet wide 7.9 feet high, and perhaps that will rid backwall-reflections that are causing dips/peaks at my listening-position.

Or does it make more sense (1st reflection wize) to have backcorners plus center-backwall trated, rather than frontcorners plus center-backwall treated?

.::.experiment while waiting for the mineralwool to arrive.::.

1. After testing out a couple of different speaker placements i ended up moving the speakers 6 inches closer to front wall than before, and 2 feet wider apart than before, this slightly evened out bass response at listening position plus improved stereo width&imaging.

2. Moved the sofa 50cm away from the backwall & placed my bed behind the sofa.
Put as much stuff as possible into my back corners , the boxes/crates are filled with CDs in Jewelcases, Book & Magazines, Cables + random junk etc.. clothes, cased acoustic guitar and whatnot. this resulted in tighter and more even bass/low-mid @ listening position + further back.

I'm feeling pretty confident that the [PAROC NRS 2t] will do a much better job than the junk i put in the back

[Rednose]

I would just build some superchunks man!
$400.00 seems alot, you can build a super chunk 7 feet high for about $100.00 out of 703 and covered with burlap.
Its not that hard, just put plastic over your gear.
You could also make 4 panels for about $200.00, or buy some pro built ones for under $400.00 for 4 corners. That is what I would recomend.
Here is a link to my superchunks.
My Super Chunk

I was going to go the easy route and pack wrapped instulation with my guitar room, but I'm glad I took the scenic route.
Check it out.
Corners - Superchunks or Panels?
Good luck!