Using 20 or 30 kg/m3 for SSC's

laagman · 14th July 2011

I'm building SSC's with a 85 cm / 33" (diagonal) front face. People have advised me to use "the lighter stuff" to fill them up.

I can get 20 or 30 kg/m3 fiberglass in my town. Which would be better for LF?

I know the only way to be sure is to buy and test both, but I thought I'd ask anyway...

avare · 14th July 2011

Quote:

Originally Posted by laagman

I'm building SSC's with a 85 cm / 33" (diagonal) front face. People have advised me to use "the lighter stuff" to fill them up.

I can get 20 or 30 kg/m3 fiberglass in my town. Which would be better for LF?

I know the only way to be sure is to buy and test both, but I thought I'd ask anyway...

The 20 kg/m³ is better for SSCs.

Andre

jdebonth · 14th July 2011

Isnt flow resistivity the important material property to get right? All the acoustic absorption calculators work based on this, density is not an input. I do not think they have a linear correlation.

Are there are calculators available designed for SSC's?

laagman · 14th July 2011

Quote:

Originally Posted by jdebonth

Isnt flow resistivity the important material property to get right? All the acoustic absorption calculators work based on this, density is not an input. I do not think they have a linear correlation.

Are there are calculators available designed for SSC's?

You must be right, but local dealers here don't know what flow resistivity means. They just inform sizes and density.

I haven't found a calculator for SSC's yet. Maybe the mathematics are more difficult because of their triangle shape.

Max Dread · 14th July 2011

Quote:

Originally Posted by laagman

Maybe the mathematics are more difficult because of their triangle shape.

I think that is part of the equation, the other being the fact that bass behaves differently (and more complexly???) in corners.

As for correlation..... I'm by no means an expert. I think there is a rough correlation but then there are exceptions too. As Avare said in another thread, density can be a good indicator of the GFR.

A couple of relevant threads (and a coupe of links within them to other threads):

Another Gas Flow Resistivity Question - difference between "facewise" and "edgewise"?

Superchunks - keep my RS60 or change to pink fluffy? Please vote/advise!

This second one has a couple of graphs toward the end which give a rough indication of the correlation for reference.

avare · 15th July 2011

Quote:

Originally Posted by jdebonth

Isnt flow resistivity the important material property to get right? All the acoustic absorption calculators work based on this, density is not an input. I do not think they have a linear correlation.

Are there are calculators available designed for SSC's?

What is your point?

Andre

jdebonth · 15th July 2011

Quote:

What is your point?
Andre

Andre, as much as I appreciated your input on the other thread I started, how exactly is my point not obvious?

14th July 2011	#1
laagman Gear Head Joined: Jun 2011 Location: Salvador, Brazil Posts: 59 Thread Starter	Using 20 or 30 kg/m3 for SSC's I'm building SSC's with a 85 cm / 33" (diagonal) front face. People have advised me to use "the lighter stuff" to fill them up. I can get 20 or 30 kg/m3 fiberglass in my town. Which would be better for LF? I know the only way to be sure is to buy and test both, but I thought I'd ask anyway... Last edited by laagman; 14th July 2011 at 07:27 PM.. Reason: typo

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14th July 2011	#3
jdebonth Gear interested Joined: Jul 2011 Posts: 14	Isnt flow resistivity the important material property to get right? All the acoustic absorption calculators work based on this, density is not an input. I do not think they have a linear correlation. Are there are calculators available designed for SSC's?