which type of stuffing?

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a handy tip i got when asking a similar question at the decware forums:

a very cheap and effective material is the woollen stuffing you find in some sleeping bags, etc. it looks like those grey army blankets you buy at surplus stores, but all shredded.

i have no idea though where you could buy it without having to buy something already stuffed with it, but why couldn't you just buy some of those blankets and then shred 'em yourself somehow?

i've read all over the place that wool is the bees knees for this application, e.g. high -end transmission lines are frequently stuffed with "long fibre" wool apparently.
 
Just filled 2 of my wall with rockwool sound proofing batts, it made of a mixture of molten Basalt rock and blast-furnace waste material and is available in number of densities.

With the 2 interior wall filled with rockwool and the others fibreglass or Dacron, walking into the room gave me that acoustically dead suck you brains out feeeling.

The advise on the wrapper said to use gloves and a mask when installing, can give you the itches like fibreglass.

As for wool (from sheep) its a very complex fibre
<a href="http://www.higginsinsulation.com.au/wool.html"><img src="http://www.higginsinsulation.com.au/woollge.jpg" ></a>


James
 
""As for wool (from sheep) its a very complex fibre""

Whoah! you're not kidding are you?:D

maybe I should shove a couple of sheep in each box:D Once the kicking subsides I'd be left with a lovely sounding speaker..

But seriously, I asked my supplier about wool and he suggested the BAF stuff. I still went for the wool in the mids though. I suppose I could try both and see if I can hear a difference...

Rob
 
Hello Dave, Navin

Still keeping this thread alive! Dave, I downloaded the baffle spreadsheet, but it seems to only do triange, quadrangle etc, no circular stuff. I think I'm going to make the enclosures for the big tweeter (sorry, but I cant bring myself to hack nearly £300 worth of tweeters up!) into some sort of teardrop or elipsoid shaped thing ie the front plate will look egg like from the front, with the baffle curving away and outwards from the front back. I'll post a shaky mouse drawn pic in a moment..(tried to draw this freehand, but so terrible that I'll wait till tomorrow and do it on cad at work....)

This will make all baffle edges different distance from tweeter, and give a big radius edge aswell..

btw, the tweeter dome is inset into a 'horn' or radius edged hole, and the face plate is concave. - Surely this must have been designed to help?:confused: - wouldnt the baffle edge be the outside of the hole its set into?, followed by a series of other reflections on the "real" baffle?

Am I babbling?:D

Cheers
Rob
 
frugal-phile™
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RobWells said:
but it seems to only do triange, quadrangle etc, no circular stuff. I think I'm going to make the enclosures for the big tweeter

Can you approximate it with a many-sided polygon. Just keep in mind that the circle with the radiator in the middle is worst case.

btw, the tweeter dome is inset into a 'horn' or radius edged hole, and the face plate is concave. - Surely this must have been designed to help?:confused: - wouldnt the baffle edge be the outside of the hole its set into?, followed by a series of other reflections on the "real" baffle?

Can you point me to a picture. It might be possible to rear mount the tweeter and have the enclosure/pod "flow" out from the recessed part.

dave
 
That sounds good - heres a pic:

Cheers
Rob

btw: posted a small package of BAF yesterday..
 

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""Weird shape, looks like flush mount into your baffle-let, with perhaps a little woolfelt star.""

Any objections to mottled leather rather than woolfelt? - I'm pretty into aesthetics (I hope I spelled that right:D )

I'm still waiting from the distributers for an answer re: acoustic centres - looks like once they have your money...........:rolleyes:

Do you reckon the baffles are designed a bit spesh then?

I kind of bought these on an extravagent whim - was going to use the £50 ea lot, but got into an "its only a bit more for these, and then a bit more for these" etc etc...

I should add that I'd never have started this project if I had'nt seen the naim 3-way x-overs.....
I thought, all I need to do is stick 3 great drivers in a time aligned cab, use a 3-way active x-over and I'll get the best speakers in the world(TM)

Ooops:eek:

Rob
 
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RobWells said:
perhaps a little woolfelt star

Any objections to mottled leather rather than woolfelt? - I'm pretty into aesthetics (I hope I spelled that right:D )

The purpose of the woolfelt is to absorb any surface waves before they get to the edge to diffract. This can be stiffened on the back and used as a grill frame.

Do you reckon the baffles are designed a bit spesh then?

Huh. ???????????????

dave
 
wool felt is good I have used it.
another solution I have found is 2-3mm foam covered in thin muslin cloth. stick the foam and stick the cloth to the foam. the cloth is for cosmetic purposes only.
leather is something i want to try if I can fidn the right quality of leather. Sonus Faber does this.
I used the same tweeter rob on my present MTM, the option I used was to flush mount the tweeter and sand the baffle to be abasolutely fluch with the tweeter and to provide a smooth transistion. I had to use 30mm MDF on this and ust was everywhere.
One day I will rework this system....
 
""can the die cutter cut at an angle?""

'fraid not, how thick is the felt? - I'm pretty sure I can sort something out...

btw, if it is thick enough it will cut with a bevel anyway...(blades are bevelled 45 degrees at top, and this will squash material down on edges if it is thick enough..)

Rob
 
frugal-phile™
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RobWells said:
'fraid not, how thick is the felt? - I'm pretty sure I can sort something out...

felt-star-BD-pipes.jpg


It is kind of hard to make out but the cut edges of the star are beveled back ~ 45 degrees so that there are no fixed distances anywhere. The felt is a 1/2" thick. Odd number of points -- 13 in this case (its primeness may or may not be important).

dave
 
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