Author Topic: Group buy for some fibreglass / rockwool  (Read 6392 times)

Online Doge

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Re: Group buy for some fibreglass / rockwool
« Reply #15 on: February 18, 2015, 09:12:47 PM »
Not worried about the density, but the thickness, if this pricing is indicative of the 50mm stuff EnergyLite's gone up like 50-60% in less than a year

Offline Atjan

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Re: Group buy for some fibreglass / rockwool
« Reply #16 on: February 18, 2015, 10:25:19 PM »
47.5 is quite lightweight , the reason im using it and 25mm is not to kill the room , Im using it behind around 65m2 of acoustic paneling.

If you have a look here: http://www.bobgolds.com/AbsorptionCoefficients.htm you'll notice that 25mm panels typically have absorption coefficients near 1 from about 1kHz. This drops drastically to under 0.1 at 125Hz. In fact, all densities and thicknesses are like very efficient from the upper midrange. Only when you go to 75-100mm thick, you find that they become as effective lower down - the 100mm thick bat is as effective at 125Hz as it is at 4kHz. This basically means that if you use the 25mm bats all over the place, you will end up with a sucked out upper mid-range and treble and the lower registers will continue unchanged. IMO, your best bet is to have fewer, thicker panels if you want to have a more equal attenuation of reverb in your room.
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Offline Timber_MG

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Re: Group buy for some fibreglass / rockwool
« Reply #17 on: February 18, 2015, 10:55:07 PM »
If you have a look here: http://www.bobgolds.com/AbsorptionCoefficients.htm you'll notice that 25mm panels typically have absorption coefficients near 1 from about 1kHz. This drops drastically to under 0.1 at 125Hz.

Rodney is using them behind a cover with a fairly low opening area from what I can tell and an air gap. It might be useful down to 150Hz or so or perhaps lower if the slats are tuned.

Offline CAD

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Re: Group buy for some fibreglass / rockwool
« Reply #18 on: February 19, 2015, 04:53:52 AM »
Egoli had stock of 50mm Uthermo 8 and I ordered a bag of 10.
Was around R1750 including delivery.

Im going to experiment with some panels behind the speakers  :thinking:

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Offline Rotten Johnny

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Re: Group buy for some fibreglass / rockwool
« Reply #19 on: February 19, 2015, 05:17:17 AM »
Abu, I've forwarded my last proforma incl. contact details etc.  Call me if you need help.
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Offline Abu

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Re: Group buy for some fibreglass / rockwool
« Reply #20 on: February 19, 2015, 07:20:02 AM »
Thanks.. received and have requested pricing.

Offline Rotten Johnny

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Re: Group buy for some fibreglass / rockwool
« Reply #21 on: February 19, 2015, 07:29:36 AM »
Not worried about the density, but the thickness, if this pricing is indicative of the 50mm stuff EnergyLite's gone up like 50-60% in less than a year
Sorry, meant thickness, not density, albeit it holds for both.  Double thickness = roughly 2x price.
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Offline Rotten Johnny

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Re: Group buy for some fibreglass / rockwool
« Reply #22 on: February 19, 2015, 07:31:03 AM »
Thanks.. received and have requested pricing.
Feel free to use same co details - it's on their books and avoids questions re trade/end user.
Audiophile: There is almost no other group that prides themselves more on wasting good money on utterly worthless ****, and then trying to furiously blow smoke up their own ass to justify it.

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Offline Abu

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Re: Group buy for some fibreglass / rockwool
« Reply #23 on: February 19, 2015, 08:25:30 AM »
Feel free to use same co details - it's on their books and avoids questions re trade/end user.

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Offline MadHat

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Re: Group buy for some fibreglass / rockwool
« Reply #24 on: February 19, 2015, 10:22:47 AM »
Could someone post a picture of the items?

Online Doge

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Re: Group buy for some fibreglass / rockwool
« Reply #25 on: February 19, 2015, 10:43:22 AM »
Sorry, meant thickness, not density, albeit it holds for both.  Double thickness = roughly 2x price.

Confirmed by CAD's post, stuff's getting pricey.

Still think it's not a bad idea to use 100mm Uthermo 6 or 3 for super chunks, never seen anyone do it though, not sure which one would work best.

Timber_MG, lower density stuff seems like your area, could you shed some light on the merits?

Offline Abu

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Re: Group buy for some fibreglass / rockwool
« Reply #26 on: February 19, 2015, 11:13:21 AM »
Could someone post a picture of the items?

Stealing LocknLoad's picture of 50mm uThermo 8 boards


Offline Timber_MG

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Re: Group buy for some fibreglass / rockwool
« Reply #27 on: February 19, 2015, 01:38:28 PM »
Use low density if you understand the application, if you have very deep treatment panels (for example my oversize corner traps use it but my wall panels use Rockwool)

Isover Rockwool is substantially less dense than specified. While it may not be a bad thing (acoustic performance of rockwool can differ greatly on how fine the material is spun) you may want to look at other sources as well.

Online Doge

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Re: Group buy for some fibreglass / rockwool
« Reply #28 on: February 19, 2015, 02:12:15 PM »
Use low density if you understand the application, if you have very deep treatment panels (for example my oversize corner traps use it but my wall panels use Rockwool)

How low can you go? How oversized are your corner traps?

I was just thinking that one could fill a 240 x 85cm faced corner trap with Uthermo 3 for about R800, but in a trap that size (60 x 60 x 85cm triangle profile) would Uthermo 6 be more effective?

Offline reactor_sa

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Re: Group buy for some fibreglass / rockwool
« Reply #29 on: February 19, 2015, 03:39:59 PM »
Don't forget the boards with a membrane on one side, they are more effective than regular panels for the low frequencies