I reread.

Guess I'm putting the "fluffy" somewhere else or getting out the sawsall.

For below 100hz, would getting out the sawsall be recommended?

I understand that things are designed to work certain ways, and adding to designs sometimes won't effect there performance. But if the Built trap saddled only addresses (sorry, I don't remember if it was 150hz or 250hz) down to a certain frequency, why would the "fluff" not address the lower frequency that it's rated for? As if they seam to be serving and addressing two separate roles. One augmenting the other.

Thank you.
Rich

To restate:

Yes, the compressed material must be unwrapped and uncompressed in order for it to be effective in the lower frequencies.

It is a bit fascinating to watch this urban legend unfold whereby some think they can used highly compressed material as bass traps.

And on the other hand, it speaks volumes regarding the placebo effect and the power of belief.

As regards the Sawzall...I am not clear as to what it is that you are wanting to cut that you are proposing encasing in fluffy stuff. But if you are going to go the porous route, for LF bass traps you want to use LOTS of pink fluffy stuff. More (thicker) is definitely better.

Thanks SAC,

From what I was talking about with the sawzall, was, instead of standing the 2' wide x 8' 7" high x 6' deep built bass traps in the corners, I'm now considering cutting them in half to hang on the walls at reflection points, and instead, to fill the corners with Fluffy stuff. I think.

Or may go with the original game plan and install the saddle. I'm getting confused. Not to put you out, and I appreciate all that all of you have been suggesting, but, if you could pull up the IR I sent and check the response of my room to see if I should install the Saddle base trap, or do the fluffy fill bass trap.

May I Try With A Fresh Slate: Room Analysis Suggestions

13th post down is IR.

If you could check it out that would be great, if not thats ok too.
As mentioned, I mainly started researching how to treat a room because I felt I was just getting too much bass (little did I know about all of the other issues I'm having). Would the IR show which method I should use? I'm still at a point that I could put the fluff in if that would be better and I was advised to.
Sorry to the OP for stepping on any toes.

Thanks again for all the help.
Rich

Perhaps you are getting a bit swamped in the various measurements and what they indicate.

For LF modal issues, you want to use the waterfall display. From it you can identify frequencies where you have persistence - where the energy at various frequencies sticks around a bit longer in time than at other frequencies.

Ideally, with some room mapping to identify the distribution of the modal peaks, this helps to determine the optimal points for positioning trapping.

Otherwise, if you are going to use porous corner traps, you make them as large as possible and apply them to the various corner intersections in the room using low density 'pink fluffy stuff' - the generic insulation used for attics and walls that is fully fluffed. The common Superchunk design calls for 24" wall interfaces with an ~34" face frame straddling the corner.

Broadband panel absorbers are placed on the walls (and ceiling as a 'cloud') in order to damp early reflections. These are indicated in the ETC response (of which we pointed out a few issues requiring attention). The panels are positioned such that the specular reflections are intercepted at the wall boundaries. Typically these utilize ~3#/ft^3 semi-rigid Fiberglas (e.g. OC703 or Knauf Ecose) panels and are at least 4" thick spaced 4" from the wall for maximal effective bandwidth.

There are a number of practical ways the panels can be effectively positioned. Placement is indicated by reading the ETC and determining the travel distance or by moving panels such that they damp the particular reflection of interest in a subsequent measurement. Likewise a mirror can sometimes be used to identify the simpler reflections.



You would most probably benefit from using the large 'fluffy' Superchunk style corner traps for low frequency persistence. You will want to measure before and after. Without benefit of this it is difficult to quantify the exact change.

Does this help summarize and straighten out the choices for porous absorber use?

Yes it does SAC,
Thanks for taking the time "yet again" to go through this.

Rich

Waaait a second...

Soo here I was about to build a bunch of 4" thick floor to ceiling rockwool traps to straddle across my rooms corners, and now I read all this talk of fluffy superchunk traps being a better bet.

Good... that will save me a few bob.. but there was mention of the mixing of materials. Does this apply strictly to the construction of the superchunk? or the room in general.. I still have clouds to put in.. was going to use rock wool.

Just trying to get a few facts right.

Hey Dayl,
From what I got of it though, the "fluffy" (could someone come up with a better name or referral?) will get to lower frequencies and you'll need more of it and it will take up more room. You're rockwool corner trap would saddle at 24" across about 17" out. You're "Fluffy" will saddle like 34" across about 24" out.

"Does this apply strictly to the construction of the superchunk? or the room in general.. I still have clouds to put in.. was going to use rock wool."

I'm guessing here that the density of the rockwool makes it shallower for your wall and cloud traps (also using the combination of the gap of "air" between the rockwool and wall or ceiling. Fluff gets completely filled... If you where to use Fluff method you would really be penetrating into the room.

Just to add... (hopefully it's not widely incorrect)
From what I'm told fluffy should be about 15" deep. So your fluffy trap could take up the same space (or be behind) a corner straddling bass trap. It seems that oftentimes (presumably because of the low cost?) people build fluffy cornertraps that are 24" deep with a 34" face, but it's not a minimum requirement.

Typically the rigid traps are used in clouds because they're rigid (so they don't sag down onto your head) and also because they take up less space (4" deep+air gap vs 15" deep).



Now to sit back and wait for SAC to smite us

Boo!!!


The 'pink fluffy stuff' corner Superchunks and the 4" broadband panels are covered in post #64.

Generally speaking, you want to avoid mixed 'densities' in absorbers unless you know exactly what you are doing.

Ah!!!

heh

Oh no! Who am I ever gonna call for help?!?!?!



Oh, howabout these guys?



(Note: Ghostbusting may affect low frequency response, check with your local acoustician before significant busting of any kind)