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Tim's Limp Mass Bass Absorbers
Old 3rd September 2019
  #961
Here for the gear
Quote:
Originally Posted by diggo View Post
You left out the most useful method for very small rooms: pressure absorption, which is similar to limp mass 'membrane absorption' but not the same. It consumes significantly less space in the room.
Sorry my bad It was kinda late in the morning haha i still have vacation...
This whole new adventure sucked so deep into it, that i sometimes forget sum details haha

I was aware of it that a limp mass bass absorber is a pressure absorber also, same as helmholthz, but helmholtz is gonna be the last option for me, cuz imo they look quite difficult to built..
I haven't did a really deep search on them...

But are there also membrame absorbers which aren't pressure based?
Still learning tho

Quote:
Synthpark wrote:
Quote:
Originally Posted by diggo View Post
You left out the most useful method for very small rooms: pressure absorption, which is similar to limp mass 'membrane absorption' but not the same. It consumes significantly less space in the room.
Membrane and Helmholtz are both pressure absorbers.
Yes u are totally right about that also
Old 3rd September 2019
  #962
Here for the gear
Can someone tell me if this is possible to build such pressure device? which is actually works?

Imo it looks kinda interresting building 1 device that handles 2 narrow frequency bands which saves up space...
The only thing i'm worried about are the blue & green calculations due the Porous Absorbent after the maembrame which might not work because there must be sum space between them.
By adding a small air gap the whole calculations will change...
and in this calculator it ain't possible to add an extra gap..
I'm bad in math.. long live those calculators

Imo the red calculations have to best options to realize in a working build...

I'm hoping also if someone can tell me what's best the best thing to with superchunks and limp mass absorbers?
Should i place a limp mass in the corner & build super chunks on top of them, or build a superchunk from floor to ceiling & place the limp mass near them or somewhere else...
As far as i understand the real low frequency limp mass absorers have to be placed in the corners for the best results
Attached Thumbnails
Tim's Limp Mass Bass Absorbers-absorber-test.jpg  
Old 3rd September 2019
  #963
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There's a very long thread here which contains all you need to know regarding 'modex' plate-based pressure absorbers, which can give you the best low frequency bang for the buck when factoring in the loss of space in small rooms due to room treatment. That assumes the boundaries (walls, ceiling, floor) don't offer useful bass trap potential beyond the boundaries.
Old 3rd September 2019
  #964
Here for the gear
Quote:
Originally Posted by diggo View Post
There's a very long thread here which contains all you need to know regarding 'modex' plate-based pressure absorbers, which can give you the best low frequency bang for the buck when factoring in the loss of space in small rooms due to room treatment. That assumes the boundaries (walls, ceiling, floor) don't offer useful bass trap potential beyond the boundaries.
Your link didn't work cuz there was "http://" at the end...
But damn that looks like an veery interessting thread tho!

I allread build sum super chunk frames & have rockwool etc.
so it's better to leave those behind..

I only readed the first page of that thread...
Ahh maaaan this acoustic adventure is going to a brain cracking adventure..
So many options

Last edited by Davo013; 3rd September 2019 at 04:26 PM.. Reason: fault
Old 3rd September 2019
  #965
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akebrake's Avatar
 

Quote:
Originally Posted by diggo View Post
There's a very long thread here...
Hi Diggo

For some reson your link is broken, Try this one

My Experiment with a Metal Panel Absorber
Old 3rd September 2019
  #966
Here for the gear
Should i continue building super chunks? and go for a Metal Panel Absorber afterwords or just skip them chunks?
They act like broadband absorbers also, so that makes me doubt about it

Pfft i think i'm going to run short on space on my backwall if i want to put a diffusor on it lol with the chunks there's only 147cm width & 256 height space left for a pressure absorber & diffusor
It appears to be that those metal absorbers are quite big..
but i haven't read the whole thread.. Maybe i'm wrong about that..
Is so maybe limp mass would be a better option for me..
Old 9th September 2019
  #967
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It’s measured. Very small space and unusual construction - garden office SIP kit, although the room would have lower modes in the model, it doesn’t in reality due pretty much everything below 100hz just passing right through the walls. Mixed blessing as I need to be careful with volume when working, but have a flat bass response, apart from 164hz. It’s one of the main modes for the room size as well as measured. We’re talking rockwool for this? I put up some panels for my last from and they don’t help at this frequency.


Quote:
Originally Posted by nms View Post
Is this something you measured, or just calculated?
Any reason you're not treating this with porous absorption? 164hz is easy to deal with using broadband absorption. Tuned traps are meant to target the sub frequencies where porous absorption is less effective, in rooms which have massive boundaries (concrete or multi-layered drywall). It's the wrong direction to go for dealing with 164hz. Worse results, higher cost, and more work are the likely outcome there.
Old 10th September 2019
  #968
nms
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Quote:
Originally Posted by benferrari View Post
164hz. It’s one of the main modes for the room size as well as measured. We’re talking rockwool for this? I put up some panels for my last from and they don’t help at this frequency.
If they didn't help, the panels weren't designed well (too thin or wrong insulation type are common) or they weren't placed in the right location for the problem you are targeting. To put it one way, if you hang a curtain on your wall instead of in front of your window, it's not going to block the light. All around your room there are surfaces which cause acoustic interference of varying nature and severity. Even if you followed good advice in treating the usual spots, all it takes is one untreated reflection point in the right place to cause an issue that no amount of treatment in other areas will fix. Sometimes it's the desk and the only way is to replace with something which causes less acoustic interference.
Old 13th September 2019
  #969
Gear Head
 

I built 8 of these absorbers out of nice quality baltic birch plywood and the heavier MLV. They are in storage right now and I'd like for somebody who has use for them to take them if they like. I'm in the Seattle, WA area. If anybody is interested I can get exact dimensions. They were a lot of work so hoping this would save somebody some effort.
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