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Generic names for acoustic treatment materials
Old 2 weeks ago
  #1
Here for the gear
 

Generic names for acoustic treatment materials

I live in South America (Colombia), so shipping from treatment providers like GIK might be prohibitively expensive. I'm waiting on some quotes, but in the meantime I'd like to look into a more DIY approach since I have access to very inexpensive labor to build this stuff.

But I need to locate the proper materials and I assume there will be different brands available here, so I will need to better understand the generic properties of the materials in order to know what to look for (unless, of course, someone knows specific brands available here in South America).

The first thing I would like to build (since it will likely be the most expensive for GIK to ship) would be corner bass traps. My front wall is 14' across and I would like to cover left/right corners AND the ceiling.

The room is 23' long and also has a 7' x 14' extra room that the main room open into on one side (just adding this info for context). I can make the corner treatment pretty deep since I'm not really using those corners for anything.

Questions:

1) What are the best materials for this (I know Rockwool and Owens Corning 705 get suggested, but so far haven't found a supplier selling either so I need more generic names/composition/density numbers)?

2) If I'm custom building the side & ceiling traps, are there any specific dimensions that people have found work best and optimize for efficient usage of materials?

Note, I did a bunch of searching around on this site, but this is a topic where searches just yield too many false-positive results to dig through, And most of the "stickies" seem more about general acoustic principles rather than the specific info I need.

Gracias!
Old 2 weeks ago
  #2
Gear Nut
 
Mark Alpine's Avatar
http://www.acousticmodelling.com/porous.php

Here you can play around with thickness, air gap and gas flow resistivity (GFR). For bass traps you should pick a insulation material w/ low GFR (~5000 rayls/m) and thick (>50 cm). For early reflection points (creating a reflection free zone) they are normally thinner so a higher GFR with a slight air gap is more suitable.

For a ceiling being 2.45 m high, the first floor ceiling axial mode (frequency build up) happens around 70 Hz, so try to design the ceiling could thick enough to tackle this frequency.

Density is somewhat correlated to GFR but not always. Try to make a list of insulation brands near you and check their homepage for GFR values.

Good luck!
Old 1 week ago
  #3
Here for the gear
 

Quote:
Originally Posted by Mark Alpine View Post
http://www.acousticmodelling.com/porous.php

Here you can play around with thickness, air gap and gas flow resistivity (GFR). For bass traps you should pick a insulation material w/ low GFR (~5000 rayls/m) and thick (>50 cm). For early reflection points (creating a reflection free zone) they are normally thinner so a higher GFR with a slight air gap is more suitable.

For a ceiling being 2.45 m high, the first floor ceiling axial mode (frequency build up) happens around 70 Hz, so try to design the ceiling could thick enough to tackle this frequency.

Density is somewhat correlated to GFR but not always. Try to make a list of insulation brands near you and check their homepage for GFR values.

Good luck!
Thanks! I'm thinking it will be a lot cheaper in the end to just custom build the entire front wall, at least the corner bass traps. At a minimum, I think I will want to both sidewall corners and the ceiling. Perhaps the front part of the sidewalls too.

I know it is best to treat corners, but I also have a few places in the room with unused space that I could easily fill with bass absorbers using the insulation. They aren't in first reflection points, but I'd think that absorbing low end energy anywhere would have a positive effect.

Is that the case or should I only be looking at the corners?
Old 1 week ago
  #4
Gear Nut
 
Mark Alpine's Avatar
Quote:
Originally Posted by Gr8fulPickr View Post
Thanks! I'm thinking it will be a lot cheaper in the end to just custom build the entire front wall, at least the corner bass traps. At a minimum, I think I will want to both sidewall corners and the ceiling. Perhaps the front part of the sidewalls too.

I know it is best to treat corners, but I also have a few places in the room with unused space that I could easily fill with bass absorbers using the insulation. They aren't in first reflection points, but I'd think that absorbing low end energy anywhere would have a positive effect.

Is that the case or should I only be looking at the corners?

I would do bass trapping in all corners, RFZ including a thick ceiling cloud and if you have the space treat the whole back wall with thick insulation (>40 cm, preferably thicker) having suitable gas flow resistivity. If your room ends up too dead you could consider adding some diffusion to the back wall (given that the room is long enough that is).

The back wall is very important to treat (main contributor to modal activity once the RFZ and corner traps are in place). I have a room where I cannot do much there, but you might be in another position.

Get a measurement microphone and see where you have issues. Use REW, there is an excellent post (sticky) here that will get you up to speed using that software.

Velocity based traps are easy to design if you have the space. Other traps like helmholz resonators, VPRs and membrane traps are more difficult to design (I have no experience yet) but highly effective if you want to target problematic frequencies. Since these traps are pressure based, they need to be located where the problems are.

"Less is more" does not apply for acoustics unfortunately...
Old 1 week ago
  #5
Gear Nut
 
Mark Alpine's Avatar
I would like to stress out that I'm not a professional like some people on this forum (you know who you are!). I've just browsed around here for some time now trying to suck up as much info I can on the topic. I'm also in a position where I'm trying to upgrade my home studio acoustics. I'm soon going to do the initial measurements of my room - I'm looking forward getting some feedback from the pros on what to do next.

/Cheers, Mark
Old 1 week ago
  #6
Here for the gear
 

Quote:
Originally Posted by Mark Alpine View Post
I would like to stress out that I'm not a professional like some people on this forum (you know who you are!). I've just browsed around here for some time now trying to suck up as much info I can on the topic. I'm also in a position where I'm trying to upgrade my home studio acoustics. I'm soon going to do the initial measurements of my room - I'm looking forward getting some feedback from the pros on what to do next.

/Cheers, Mark
The challenge for me will be locating the materials. My Spanish isn't great and this kinda technical stuff is even harder to explain via a translator.

A guy I know here who sells high end recording equipment suggested this companies products, but I don't know enough to know if this would be the right material. It's thin, so I'd have to use more.

This seems to be the most ideal thing they sell. Thoughts?

I'd still like to find materials not specifically sold as "acoustic" treatment materials since that usually means $$$$, but if it is the right stuff then whatever.

NRC: 0.7 (1 in) NRC: 0.9 (1.1 / 2 in)

https://www.isover.com.co/productos/acustifibra-r
Old 1 week ago
  #7
Here for the gear
 

Quote:
Originally Posted by Mark Alpine View Post
I would like to stress out that I'm not a professional like some people on this forum (you know who you are!). I've just browsed around here for some time now trying to suck up as much info I can on the topic. I'm also in a position where I'm trying to upgrade my home studio acoustics. I'm soon going to do the initial measurements of my room - I'm looking forward getting some feedback from the pros on what to do next.

/Cheers, Mark
Found this as well:

http://acustec.com/SVsitefiles/produ...a_sonowall.pdf
Old 1 week ago
  #8
Lives for gear
 
Jason Foi's Avatar
 

Insulation. There is nothing fancy. Same stuff that goes in walls and attics.
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