UK equivalents to 703 and 705 and density Q

[Arksun]

I often hear 703 and 705 mentioned on this board but, as these aren't standard types in the UK, what exactly IS the exact equivalent to these?.

I found this site which seems to sell a varied choice of options:

Dense Fibre Matting Acoustic Slab - The Sound Solution, York, UK

Comes in different thicknesses and densities of rock mineral wool slabs all the way up to 140KG/m3!.

But I think I remember reading somewhere that if the density is too high and you're having something 3-4 inches thick, that it can start to reflect the sound as well as absorb, rather than just absorb :/

So lets say I was buying some material from this place for a bass trap to deal with the lowest frequencies (everything under 100hz), what out of those options would be the most ideal thickness and density to absorb without reflecting?.

Something like 100mm 80kg/m3 or 75mm 100kg/m3 ??

[PaulP]

Originally Posted by Arksun

I often hear 703 and 705 mentioned on this board but, as these aren't standard types in the UK, what exactly IS the exact equivalent to these?.
...
Something like 100mm 80kg/m3 or 75mm 100kg/m3 ??

703 is 48 kg/m3 :

703 data sheet

I believe it is better to use thicker lighter stuff than thinner denser stuff.
You'll probably have more luck with rockwool in the UK.

Paul P

[nigel saunders]

something like

Rockwool:
2 x RWA45 4 pack (1200x600x100) code 107524

theres a thread here I think

My new cheap bass traps (pics, prices, suppliers in London)

[Arksun]

Originally Posted by PaulP

703 is 48 kg/m3 :

703 data sheet

I believe it is better to use thicker lighter stuff than thinner denser stuff.
You'll probably have more luck with rockwool in the UK.

Paul P

Ahh I see, so I would probably be better going for the 100mm thick 45kg/m3 rockwool then?.

At that lower density, could I even double that up, two slabs making it 200mm thick for corner traps?

Am I right in also thinking that, being a bass trap and not so much for broadband use, that it doesn't matter if the material is a bit thicker than normal? (concerned about the health side of things, dont want fibres escaping).

[PaulP]

Originally Posted by Arksun

At that lower density, could I even double that up, two slabs making it 200mm thick for corner traps?

The thicker the better. 200mm is reasonable.

Am I right in also thinking that, being a bass trap and not so much for broadband use, that it doesn't matter if the material is a bit thicker than normal? (concerned about the health side of things, dont want fibres escaping).

People have wrapped the rockwool in polyester batting to minimize fallout.
Thicker can't hurt anything.

Paul P

[Arksun]

Originally Posted by PaulP

The thicker the better

Cool, so for triangle shaped corner traps, if the fibre was cut as triangle cuts, they could just be stacked on top of each other so the thickness could extend all the way to the corner.

Was a right in thinking that the much higher density stuff would indeed have a detrimental effect at greater thicknesses?

[nigel saunders]

Originally Posted by Arksun

Cool, so for triangle shaped corner traps, if the fibre was cut as triangle cuts, they could just be stacked on top of each other so the thickness could extend all the way to the corner.

Was a right in thinking that the much higher density stuff would indeed have a detrimental effect at greater thicknesses?

As the previous poster said - the thicker the better!

There is a good video on youtube about building traps - certainly worked for me

[Arksun]

Originally Posted by nigel saunders

As the previous poster said - the thicker the better!

There is a good video on youtube about building traps - certainly worked for me

Why didn't I think of youtube, i visit it enough! lol. Thanks.

Hmmm, interesting reading a few other threads would suggest that perhaps for mineral wool, a higher density is required to match 703.

Rockwool for bass traps?

Scott states that:

To match these attributes in rockwool requires a higher density because of the nature of the material. Generally you could expect similar acoustic performance with a panel about 50% denser in grade [this would approximately match the gas flow properties of 703] which works out to about 5 lbs. per cubic foot or about 60 kg/m3. But even at this density rockwool has inferior handling properties to 703 and yields a heavier panel [no biggy for a hang forget application, but if portability matters this is a flaw].

So would I be better off getting the 80kg/m3 rock wool mineral fibre as an equivalent to the 703 45kg/m3 fibreglass?

[avare]

Several things are getting discussed here. Rockwool is broady equivalent at slightly denser at around 48 kg/m^3 fiberglas at 64 kg/m^3. the relationship acoustically is not linear.

For thick bass traps, lighter is actually better. 48 or less kg/m#.

Andre

[Arksun]

Originally Posted by avare

Several things are getting discussed here. Rockwool is broady equivalent at slightly denser at around 48 kg/m^3 fiberglas at 64 kg/m^3. the relationship acoustically is not linear.

For thick bass traps, lighter is actually better. 48 or less kg/m#.

Andre

Ok I'll probably stick to the lighter stuff then.

Although I'm starting to realise making a triangle shaped box might be a little tricky. Leaving either doing more traditional rectangle slab or square column.

Is a more square shaped column a bad idea for standing in the room corner, ie, would a wider straddled thinner (200mm x 600mm) bass trap be more affective than a less wide (but same m2 area) solid square column (say 400mm x 400mm) which would have 90 degree surface areas instead of a larger single diagonal surface area for handling the lowest of low freqs?. Or are the angles and positions of the exposed surface areas not so important for a bass trap?.

[lanmonkey]

I'm in the UK and I have been trying to find equivalents to 703 and 705 Owens-Corning in the UK.

Take a look at this datasheet for Rockwool:
http://www.sheffins.co.uk/Literature...xible_slab.pdf

on page 2 you have a list of "types and densities"
on page 3 there is a table of "absorption coefficients"

in a nutshell:
Rockwool RWA45 = 45 kg/m3
Rockwool RW3 = 60 kg/m3
Rockwool RW5 = 100 kg/m3
Rockwool RW6 = 140 kg/m3

You can buy all of these types off ebay UK, just do a search for "Rockwool RW6" for example.

All I need to do now is work out which type of basstrap to build and which desity to use

Hope this helps