I posted this about 4 years ago but didn't get around to doing anything with it....
My next Owston will hopefully feature this with my final amp build, the mofo mentioned in the other thread. The only change might be the inclusion of an FT17 tweet as I really like the contribution it makes to the triangles. I think I'm abandoning the planned slob and the rest of the unused speakers on the shelf can go on ebay.
fane trapeze60.jpeg (204.9 KiB) Viewed 2075 times
There's nowhere you can be that isn't where you're meant to be
The inner curve was screwed to the top/bottom from the outside, then the outer shell was screwed to the inner from the inside. Between the two shells there is a layer of glue and sand.
The slits in the inner and outer shell leave 5 mm unslitted so that the inner/outer surface is airtight.
Good effort! I guess it's a pretty thin layer of sand?
It looks like mdf? Musing, I guess one could perhaps use two skins of some thin mdf that could be bent to the shape with some perhaps 12mm mdf as spacer around the perimeter and with a number of small blocks distributed to hold the skins apart and make the composite rigid. The void could then be filled with sand. Might not sound any better though. And it would be rather heavy.
My experience of using thin kerfed MDF in more than one layer was very bad ( on an iteration of the mid/bass horn ) . I guess if you can manage to make sure all the voids are filled and it's tightly bonded from layer to layer it might sound a fair bit better ( if Rowuk has managed that ) . However my experiences just added to my overall distaste for MDF.
"Forever fair ... and I'm touching your hair. I wish we could be dreaming .... in this dream" ( Morrison )
IslandPink wrote: ↑Fri Oct 28, 2022 7:27 pm
My experience of using thin kerfed MDF in more than one layer was very bad ( on an iteration of the mid/bass horn ) . I guess if you can manage to make sure all the voids are filled and it's tightly bonded from layer to layer it might sound a fair bit better ( if Rowuk has managed that ) . However my experiences just added to my overall distaste for MDF.
This was my experience in a previous build too. This time I poured sand into a pot of glue for the constrained layer then applied generously. Yes, the sand layer is thin but fills all gaps and the inner and outer shell are tightly bonded with the glue and enough screws from the inside. This is by far the most inert box that I have ever built.
I cut the grooves into 15mm MDF myself, only having enough grooves to create the desired curve. I will try plywood in a future build (or combine different types of material).
. Or you could just build what you said you were going to build in the first post.
