Natural Sheep Wool for damping?

[Arash]

as you might know, there are some very expensive and hi-end speakers out there which use Sheep Wool as damping material. I really like to use it in my Conrwall. all my Conrwall's damping material is removed by previous owner... any idea about sheep wool? is it any good? how should I use it? how about thickness? .

If anyone has any inner photo of CW it could be helpful

any help is appreciated

[Panacea Engineering]

Sheep in Iran....now that is a picture for the mind......sorry as I could not resist......[]

[Arash]

Sheep in Iran....now that is a picture for the mind......sorry as I could not resist......

you DO NOT HAVE to be sorry... you're a hundred percent right... how can I defend my (freakin') country against critics while the government is the most devastating religious dictatorship ever existed?

BUT any idea about Sheep in a CW as damping thing?[]

[Panacea Engineering]

Arash,

I doubt that Sheep's Wool is any better than any other synthetic material for dampning. I would actually think synthetic is better because of the uniform cell structure. I have honestly never heard of using Sheep's Wool for this...car seats covers..yes, but NOT for speakers. This could possibly be some type of Myth or Hype, who knows....YMMV

[DizRotus]

I have a pair of 30+ year-old transmission line sub-woofers that have the lines stuffed with genuine UK wool. It's my understanding that real wool was/is used in such situations as a low pass filter. The wool filters out the high frequencies, while allowing the low frequencies to exit the line. It wasn't used as damping material, in the way polyfill (pillow stuffing material) is used as damping material these days.

I believe polyfill (available from Parts Express) would be better at damping a Cornwall than real wool. In fact, that paper padding that Klipsch used is probably better still.

When I purchased the wool from Falcon Acoustics in the UK, they recommended moth-proofing the wool before building it into the speakers. Moths don't like polyfill. There was some thinking that the natural lanolin in sheep wool enhanced the acoustic properties.

Where's Sputnik when you have a sheep question? If I were ewe, I'd forget the wool.

[Daddy Dee]

Arash,

I think wool would work fine as damping material inside the cornwall as long as the price is reasonable to your own satisfaction. There are alternative materials that would work equally well, IMO, and perhaps a less expensive solution. I'll post a pic of a cornwall interior which has damping material which looks like factory spec or something very close. The owner has also used some adhesive material to damp the woofer basket and horns. The Cornwall III's have the woofer raised on the motorboard. Klipsch engineers say this was their solution to a standing wave issue in the older cabinet configuration.

[Brac]

Arash, is it safe for you to type things like that? Yes, I'm asking a serious question. I've never know anybody from Iran, but I used to know alot of Cubans, they always had to watch what they said (internet wasn't available to Cubans at the time)

[moray james]

Arash: a reflex cabinet is damped by the reflex vent (major cavity resonance) You need to have a volume of air which can resonate to generat the energy which will feed the same frequency resonance in the reflex vent. You cannot have one without the other. That is way reflex cabinets traditionally have damping on three of the inside walls.. You might want to consider this as you may be falling into one of those if some is good more is better and too much is perfect situations. Best regards Moray James.

[garyrc]

I am SO glad that no one here said "dampening" instead of "damping," because few things smell worse than wet sheep.

[coolhandjjl]

I have read that damping should be on all surfaces, the last thing anyone wants is waves reflecting out the port.

[moray james]

no that's not the case the reason why damping was used on three of the remaining walls (motor board excluded) was because you did not want to lower the level of the cavity volume resonance too much. Just enough damping material was used to deal with internal standing wave reflections at higher frequencies and that was all. The vent is what damps the driver and the vent gets its energy from the driver/cavity resonance. You can't have one without the other. Take a look at any of the old Altec literature on cabinet design, and you will find minimal damping and on the cabinet walls not in the volume or just look at the inside of a Cornwall. Hoe this helps. Best regards Moray James.

[T.H.E. Droid]

Your Cornwalls have vents, which open to the outside air. There are many bugs that like to eat wool, and I'm not sure I want creepy crawlies munching inside my speakers. That makes it a lot easier and cheaper to stick with something that doesn't attract vermin. As for high end speaker manufacturers using wool, I suppose that's because most try to justify their rediculous prices by "pulling the wool over the customers eyes." Now you know which wool.

[coolhandjjl]

Okay, did a bit more sesearch. 1950's conventional wisdom was to damp only one of two opposing panels. After the '70s, research indicated that to keep internal midrange reflections off the cone and/or out of the port, damping additional surfaces was critical. So that makes sense that old Altec and Klipsch designs would be done like that. But for loudspeaker designs after that, having damping everywhere is the rule.

[moray james]

The rule is to keep the damping on the walls not in the cavity. If you damp the cavity you damp the energy source for the reflex vent. Yes there are some reflex boxes designed like that but that just means they are badly designed reflex cabinets. This applies equally for passive radiators as well. Best regards Moray James.

[coolhandjjl]

Just on the walls, understood. And not too thick as to decrease the interior volme either.

[moray james]

in this case the cabinet vclume is not the concern. The concern at hand is the ability of the cabinet's volume to resonate with enough energy to drive the resonance of the reflex vent(s). Damping material will actually have the affect of making the loudspeaker think that it is in a larger volume than it is. Theory says you can increase the volume this way by as much as 25% but in practice it is difficult to achieve any more than an increase of 20% using damping.If a cabinet has been properlybraced and stiffened they won't be much of an issue with standing waves inside of the cabinet because ther will be too much physical material in the way breaking up any standing waves. Attached are some links with some pictures of some different loudspekers which I have braced and stiffened. I hope that this is of some interest. Best regards Moray James.

http://www.audiokarma.org/forums/showthread.php?t=372783&highlight=klf20

http://www.audiokarma.org/forums/showthread.php?t=438234

[sheltie dave]

I tried to get a set of Cornwalls with sheep wool in the house, but our sheltie kept herding them outside.

[DavidF]

as you might know, there are some very expensive and hi-end speakers out there which use Sheep Wool as damping material. I really like to use it in my Conrwall. all my Conrwall's damping material is removed by previous owner... any idea about sheep wool? is it any good? how should I use it? how about thickness? .

If anyone has any inner photo of CW it could be helpful

any help is appreciated

Damped –line systems use a material to increase the damping effect of the line. A material such as treated lamb’s wool or poly fill is typically used.

The strands of the material create friction that damps the sound wave. This performs a filter effect to pass lower frequencies and damp higher frequencies.

Poly fill has a tendency to settle over time allowing the fibers to bunch up. This negates the friction effect. Lamb’s wool was often used because the fibers did not have this tendency and provided a more consistent performance over time. Specialty poly materials are now available that avoid the settling issues.

The use of damping material in reflex or ported systems is more to reduce the effects of standing waves. The material does not have to be attached to the walls but this is the conventional method. One of opposite walls or all walls are covered depending upon the need.

Plain old fiberglass is one of the best materials for this purpose as it is readily available and can be easily applied. Acoustic foam is likewise is easy to install but generally not as effective. Poly can be used but it is difficult to use for lining the walls.

A fill material in the open enclosure can be used in a reflex/vented box to help tune a system or alter the enclosure Q factor. This would have a similar effect of using a resistive port.

[angusruler]

i redid my cw's, my chorus II's, heresy's, quartets, and klfc7 with this stuff.

easy to work with, and a lot better looking than the old stuff in my cw's, and the gray foam in my others.

http://www.uline.com/Product/Detail/S-656/Paper-Cushioning/12-x-175-Cellulose-Wadding-Roll