Hello all, incredible thread!! Looks like so much fun, I wanna build my cornu too. I'm thinking about using Sanspeak 10F/8424G00 and core foam. I'm still wondering what is best and if I should use 1cm core foam instead of 5mm core foam boards.
Also I don't know if I should aim for 20" version or bigger.
Could you please help me in getting on my feet and try to walk through such a project?
Also I don't know if I should aim for 20" version or bigger.
Could you please help me in getting on my feet and try to walk through such a project?
Wauw... I haven't been here for a while...I like what I am reading and wow Onni! I like the pictures of your measurements....
Dedodo give it a go, you will not be disappointed. If you are going for the 1cm board then you could go for the larger size. 5 mil will give you great results when you get the stuffing right. Keep us all posted on your efforts.
Hi!!
So maybe 1cm for the front and back plate and 5mm for the inner spiral then? I read about the W4-1052SDF and the W4-1320SIF... If they are better fit for the job than the scanspeak, it's all the better, they are much cheaper!
So maybe 1cm for the front and back plate and 5mm for the inner spiral then? I read about the W4-1052SDF and the W4-1320SIF... If they are better fit for the job than the scanspeak, it's all the better, they are much cheaper!
I think the TB W4 bamboo cone is great choice in a 4 in deep x 24 in wide Cornu. Prezden has made one and reports are great.
Thicker FC on front and back and thinner in channels is a good idea. Although at sizes larger than 20 in you need to use thin plywood for front and back unless you don't mind joining sheets together.
Thicker FC on front and back and thinner in channels is a good idea. Although at sizes larger than 20 in you need to use thin plywood for front and back unless you don't mind joining sheets together.
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the TB bamboo are a little pricey in Europe, in US you get them for 35 bux, here it's 60 bux!
I read the Fostex FE 126 are not that great for the job? What about them? I love their look with white foam core cornus.
I read the Fostex FE 126 are not that great for the job? What about them? I love their look with white foam core cornus.
you mean the making the FE126 into 27"? I'm all over that, would look great too!
Frankly the superlatives adjectives about those Cornus are really intriguing and I'm still debating if I should really buy expensive versus real cheapo full drivers (10€ a piece).
I mean I have a really nice home rig already, but the fun and the beauty of this design (cornus) is what I'm after!
Really a big thanks for this thread, really inspiring, a breath of fresh air, and a nice way to make a speaker without resorting to cutting mdf and all that stuff!
Is there a big benefit using those fostex over the bamboo fiber or some cheapo Visaton FR10-8?
Frankly the superlatives adjectives about those Cornus are really intriguing and I'm still debating if I should really buy expensive versus real cheapo full drivers (10€ a piece).
I mean I have a really nice home rig already, but the fun and the beauty of this design (cornus) is what I'm after!
Really a big thanks for this thread, really inspiring, a breath of fresh air, and a nice way to make a speaker without resorting to cutting mdf and all that stuff!
Is there a big benefit using those fostex over the bamboo fiber or some cheapo Visaton FR10-8?
I'm just thinking that the extra work is not so much so why not go the exta 3" and get the extra extension? X knows more maybe he can add to that.
You are right Cal. An extra 3 in to make it 27 in x 4 in deep would sound better. 24 in was a plywood limit for small take home pieces as I recall.
The FE126EN should be a fine driver for a 27 x 4 in Cornu. Good luck and keep us posted with build photos!
Is the some sort of problem if one would put a five inch in a 27" cornu ? I'm thinking about fountek fr135
A five inch driver may have a hard time fitting the driver chamber diameter. You will have to look at driver size and scale up as needed to fit.
Edodo, I can see this becoming 15 inch driver eight inch deep and ooooo around six foot square 😉
Go for it and feel the noise.
Go for it and feel the noise.
Has anyone tried making the flare in horn height as opposed to in horn width? This would also create a flare in the baffle that could be modulated by the width of the interior horn's channel. Kind of a two for one horn. I dub it the BOGO horn if no one else has explored the idea.
I've been working on a spreadsheet to calculate this, but it's slow going. Ideally one would be able to cut the back horn's flare from a single long sheet and then arrange it in a spiral of constant or nearly-constant spacing to construct. In some ways, this makes it simpler than the Cornu. Because of the back horn's gradual curve and the spiral, the front horn could then be made using the back horn's outward and upward flare as a frame for paper mache.
I don't know. The math is a bit complicated, but I get the feeling that horns are in some ways a 'close enough' kind of calculation.
Any input?
I've been working on a spreadsheet to calculate this, but it's slow going. Ideally one would be able to cut the back horn's flare from a single long sheet and then arrange it in a spiral of constant or nearly-constant spacing to construct. In some ways, this makes it simpler than the Cornu. Because of the back horn's gradual curve and the spiral, the front horn could then be made using the back horn's outward and upward flare as a frame for paper mache.
I don't know. The math is a bit complicated, but I get the feeling that horns are in some ways a 'close enough' kind of calculation.
Any input?
Yes, I have considered this. The thing is, the expansion ratio of the Cornu is already ridiculously large at about 28:1 which provides a bass gain of about +10 dB. Anymore expansion and the bass will be overpowering. It could work if you make the channels not use up the full 360 deg of the perimeter for the mouth. Not being rectilinear will make construction a real headache. I have tried making FC tractrix horns and it is tough to predict the shape - it was trial and error with a visual projection to start with. If you did the whole thing in a 3d CAD program with a sheet metal approach to modeling, you could flatten the "sheet metal" to find the 2d form to cut.