Rockwool for ceiling - which of these would be best?

[Oli_W]

I already have 8 great GIK244s, now I'm putting in a false ceiling in both my garage and control room:

1. on page 29 of this brochure (see below) there's some RW3/4/5/6 and other rockwool, any idea how low they'll absorb? I don't want anything toooo heavy for the ceiling! There'll be a considerable air gap above.

2. Should I get RW6 for corner traps? What thickness would absorb down to, say, 50Hz?

http://www.minster-ins.co.uk/downloa...duct_Guide.pdf


Hope someone can advise!! Glenn....?

Thanks,
Oli

[avare]

How thick are you planing for? The industry standard is the rw3. Famous from all teh BBC use of it in absorbers. You will not have much diference acoustically betwena ny of the materials on that page.

Andre

[Glenn Kuras]

What thickness would absorb down to, say, 50Hz?

REALLY THICK!! Why 50hz?

[avare]

Originally Posted by Oli_W

2. Should I get RW6 for corner traps? What thickness would absorb down to, say, 50Hz?

Sorry I missed that, adding specifically to what Glenn wrote, 12" for free field absorption and 24" for normal absorption. That is based on tests published by BBC. Auntie Beeb is great for acosutical data relating to studios.

Andre

[Oli_W]

Wow - 12" is pretty damn thick!

50Hz is how low my dynaudio bm5a's reach and covers most fundamentals and the thump of my rock kicks.

The 244s in corners absorb pretty deep, and they're a lot less than 12" - are they much denser than the RW6 then?

Thanks for all the help :D

[Glenn Kuras]

Originally Posted by Oli_W

Wow - 12" is pretty damn thick!

50Hz is how low my dynaudio bm5a's reach and covers most fundamentals and the thump of my rock kicks.

The 244s in corners absorb pretty deep, and they're a lot less than 12" - are they much denser than the RW6 then?

Thanks for all the help :D

The 244 is less then 12" thick but when you straddle the corner it works much better. It has a base of 8 pound.

[avare]

Originally Posted by Glenn Kuras

The 244 is less then 12" thick but when you straddle the corner it works much better. It has a base of 8 pound.

Just adding to this for people to whom it is not clear, straddling a corner with absorbent material is creating a gap. Acousiticaly the same effect as spacing the material away from a hard surface.

Andre

[Glenn Kuras]

Originally Posted by avare

Just adding to this for people to whom it is not clear, straddling a corner with absorbent material is creating a gap. Acousiticaly the same effect as spacing the material away from a hard surface.

Andre

So Andre do you thick that if I was to space a panel in the corner to make a 12" gap (the panel flat in the corner) do you think it would be better or worse then straddling? The reason I ask is our Panel Trap can fold up and straddle the corner to act like a 6' 244 but I guess you could leave it open (making a square corner, if you can imagine that ) so it would create a 12" gap. Bryan and I have gone back and forth on that but decided that straddling was proven so we stick with recommending it that way.

Interesting subject though.

[avare]

Originally Posted by Glenn Kuras

Bryan and I have gone back and forth on that but decided that straddling was proven so we stick with recommending it that way.

I communicated poorly. I was referring to the straddling of the corner. The effective depth is the height of thr height triangle. Height in the mathematical sense. I am agreeing with straddling for creating the gap.

I hope that cleared things.

Getting confused,
Andre

[Oli_W]

Interesting!

My false ceiling in the garage will have a huge air gap, as the roof is triangular and the roof will be straight across.

The false ceiling in the control room will have about 12" air gap. So I'm hoping it'll act as a reasonable trap even with a fairly low mass of rockwool.

(I've made some diffusers for the garage too, goddamn the skyline one took forever! QRD is definitely the easiest to make...)

Thanks for all the replies - I think I'll go with the RW3, and as much as I can get!

[Glenn Kuras]

Originally Posted by avare

I communicated poorly. I was referring to the straddling of the corner. The effective depth is the height of thr height triangle. Height in the mathematical sense. I am agreeing with straddling for creating the gap.

I hope that cleared things.

Getting confused,
Andre

Ok that clears it up.