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Does anyone have any idea of the thickness of the sand layer in the old Wharfedale sand filled baffle speakers? What type of sand is used, coarse or fine?
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because they're both too young to remember such things I suppose :-)My only acquaintance with the Wharfedale sand filled baffle is 2 run-ins with them a bit over 40 years ago. The first was with a mono system and a DIY speaker, the second in a stereo system with a DIY speaker where I seem to recall the second speaker was actually made by Wharfedale rather than DIY. Both systems had quite a few years on them at that stage. I have a vague recollection of the person who made the speaker in the first system saying that there was an inch thickness of sand in the baffle.
And those systems both pre-dated kitty litter by a couple of decades.
Haven't thought about those speakers in a long time. I think I can truthfully say that it was the impact of hearing that first system while I was still quite an impressionable youth which got me hooked on this hobby. I wonder what I'd think of that system if I heard it today.
David Aiken
My first DIY speakers were Wharfedale Dovedale 3 kits (12" bass, 5" mid, 1" dome tweeter) so that will date me as an old-timer. My DIY speakers have got consistently more massive because I rate dead, dead, enclosures highly desirable. I'm ready to try the sand-filled panels but info is rather skimpy on the web. Thanks for the comment.
Bon
I can understand the idea behind the sand, and I have to admit that the idea impressed me 40 years ago. I don't think that it impresses me now to anywhere near the same degree.
What you're going to end up with is a column of sand a bit less in height than the baffle so, assuming you're considering this for a woofer enclosure or a 3 way, we're talking a baffle with a 2'-3' sand column, maybe more. While motion of the sand will initially dissipate some vibrational energy and deaden the baffle, over time the sand is going to bed down and at that point it will stop dissipating energy and start transmitting it.
I would be a lot more inclined these days to simply use something like Dynamat to deaden the baffle. If you don't want to do that and you really want to go the sand route, what I'd be inclined to experiment with is a 3 layer baffle. The inner and outer layers would simply be cut out for the drivers. The inner layer, while being cut out for the drivers, would also have a number of large cutouts distributed over the rest of the baffle. I would glue an outer layer to the inner layer, clamp them and allow the glue to dry. Once the glue was dry I would half fill the 'wells' created by the cutouts unique to the inner layer with sand. Only half or slighty more than half fill them, don't fill them entirely because you want the sand to have room for movement. Then glue the final layer of the baffle on to the other 2 , sealing the sand in what are now enclosed pockets distributed over the baffle.
I think you'll get more dissipation with less sand distributed into smaller volumes with less mass forcing the sand to bed down in each pocket. Also, with space left in each pocket, you can actually loosen the sand again at regular intervals simply by rocking the speaker from side to side a little.
I have no idea how effective this idea would be for a baffle, and I have no idea whether the pockets of enclosed air are going to cause problems, but I think in the end you'll get more vibrational energy dissipated by sand motion this way than you will if the sand space is one large void containing a high column of sand.
Overall, however, I think that simply using a material like Dynamat is likely to be at least as effective and a lot simpler to build.
David Aiken
Don't count out the extra mass loading the speaker.
I have sand in my woofer enclosures as well as
several cross braces and I love it.
DanL
Irrespective of what "TRDH" says, you can certainly use sand to fill a hollow baffle. However, really mate, it won't make the slightest difference to the sound whether it's f'ing course or fine sand, beach sand or inland sand. The only thing that matters IMO is that it is *dry* sand! :-))
Regards,
Andy
It was kitty litter. ;-)
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