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Replacing the original foam inside the box

 
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qguy
Intermediate Contributor 75+


Joined: 08 May 2003
Posts: 85

PostPosted: Tue Feb 28, 2006 7:31 am    Post subject: Replacing the original foam inside the box Reply with quote

My Kef 105.2 has this yellow hard foam inside the woofer box. Most new loudspeaker has this white stuff that is least dense compared to the foam. My question is

1. if I replace the old foam with the new white material, will the woofer see a larger box. if yes,then it means that I can make a smaller box using the white foam instead of the yellow foam right ?. Now the question is how small a sealed box can I go to get the same performance
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ColinR
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Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Tue Feb 28, 2006 11:37 am    Post subject: Reply with quote

Most KEF loudspeakers were designed with the "good" grey coloured acoustic foam in mind, not the low grade yellow muck found in most of them.

T'was the mean, evil Twisted Evil accountants wouldn't let the boys use it in production models, apart from a few "high margin" designs like the Ref 103-2.

So forget this white muck and get some of the grey and play!

Your question about using a smaller box for a B300B is somewhat spurious as the Ref 105-2's B300B already have the smallest box and highest bass cut-off of all the designs that use this particular driver.

Stick the B300B's in a Skyline transmission line or some sand filled PL301's and feel the noise Very Happy .
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qguy
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PostPosted: Tue Feb 28, 2006 11:07 pm    Post subject: Reply with quote

thanks for the info, I dont think I can get the gray foam. Not sure if the its the same material, but my Celestion Sl 6si from the mid 80's had a grayish foam inside. Upon inspection and touching it starts to disentegrate. The cheap yellow muck still holds form after 27 years plus.
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Cor van den Bogaart
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Joined: 07 Jan 2006
Posts: 15

PostPosted: Fri Mar 03, 2006 5:53 pm    Post subject: Reply with quote

Have a look at www.speakerland.nl. This is a DIY specialist selling PRITEX, one of the finest dampening materials.

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First step to take if you want to improve your system is cleaning your ears.
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proffski
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Joined: 22 Aug 2003
Posts: 1296
Location: Tewkesbury UK

PostPosted: Mon Mar 06, 2006 9:14 am    Post subject: Reply with quote

When building my TLs I too tried the different foams together with other materials. The Yellow stuff was inferior and gave completely different and wrong results when tested both on impulse and steady state evaluation. Take the good advice even though the yellow rubbish is not falling appart. There is a wealth of knowledge and experience being offered to you for free, use it and enjoy the music!
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qguy
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Joined: 08 May 2003
Posts: 85

PostPosted: Tue Mar 07, 2006 1:37 am    Post subject: Reply with quote

Colin,

ok, so what is this gray stuff called ?

you mentioned that the B300 had the smallest box and highest cut-off in this model, what other models/brands used the B300 ?
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proffski
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PostPosted: Tue Mar 07, 2006 9:32 am    Post subject: Reply with quote

It was something like Anechoic Chamber grade acoustic foam. The texture was much coarser than that of the yellow stuff. It also felt harder to the touch. Recently I have used the sculpted foam from Falcon Acoustics.

I have also had god success with Illsonic foam. Comes in different grades and materials.
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proffski
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Joined: 22 Aug 2003
Posts: 1296
Location: Tewkesbury UK

PostPosted: Tue Mar 07, 2006 9:42 am    Post subject: Reply with quote

It was something like Anechoic Chamber grade acoustic foam. The texture was much coarser than that of the yellow stuff. It also felt harder to the touch. Recently I have used the sculpted foam from Falcon Acoustics.

I have also had some success with Illsonic foam. Comes in different grades and materials. I was lucky to get some at a bankruptcy sale. I think that Canford are the only UK supplier. Seems expensive...


http://www.canford.co.uk/commerce/resources/catdetails/2661.pdf

However my PERSONAL opinion over the years is that a mixture of good quality foam and Long Lambs wool to Dr Baileys specification has worked best for me.
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