Edodo,
You can simply trim away the channels to make room for the magnet - you will probably lose 2 to 3 in of channel length which should be no big deal. Extend the size to 28 or 30 in and that will work too. Go for it! 😀
You can simply trim away the channels to make room for the magnet - you will probably lose 2 to 3 in of channel length which should be no big deal. Extend the size to 28 or 30 in and that will work too. Go for it! 😀
Thx XRK! I will post on my progress. I think I will use front and back MDF 6mm and 1cm foam core spiral or 5mm. The driver I bought are lcao 6,5" full range
Edodo,
What size will you be going with and do you have T/S params for the 6.5 in ICAO driver? I can run a sim for you and optimize the depth.
What size will you be going with and do you have T/S params for the 6.5 in ICAO driver? I can run a sim for you and optimize the depth.
6.5 in really is too big for a 24 inch Cornu - you would remove too much of the channels near the driver. I suggest 28 to 30 inch.
I think 28" is OK, 24" was only practical because of the raw MDF I could buy at this size, but I can cut MDF myself.
Lets go for 28"! Or should I say 70cm!
Lets go for 28"! Or should I say 70cm!
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Would rigidity and possibly vibration reduction be improved by using sheets of glassfibre and epoxi on both sides of the foamboard walls, after glueing them to the baffle? Just thinking loud...
Coldcut,
Yes, making the front and back more rigid should improve things - possibly a soft constrained layer like tar or rubber bonded between two stiffer layers is even better. But really the panel vibrations were really never an issue as there is a lot of inherent awl bracing from the spiral channels. Try it and let us know how it works. You need a before and after case to really compare though.
Yes, making the front and back more rigid should improve things - possibly a soft constrained layer like tar or rubber bonded between two stiffer layers is even better. But really the panel vibrations were really never an issue as there is a lot of inherent awl bracing from the spiral channels. Try it and let us know how it works. You need a before and after case to really compare though.
Hi xrk971,
I was thinking of doing something like this:
https://drive.google.com/file/d/0B2-Z6DkD83PHMWdWRjA4WGpvTkk/edit?usp=sharing
The plywood will improve the baffle rigidity, laminating the foamboard might be a shortcut to get "woodlike" properties internally.
I was thinking of doing something like this:
https://drive.google.com/file/d/0B2-Z6DkD83PHMWdWRjA4WGpvTkk/edit?usp=sharing
The plywood will improve the baffle rigidity, laminating the foamboard might be a shortcut to get "woodlike" properties internally.
Cal, 36" sure looks tempting but there would be a slight problem hanging that on the wall considering the wife vote at the decoration congress. Still 28" could be manageable.
I will try to make that plan fit this driver...
Also I have been considering recapping my father old Yamaha integrated for the cornu. It would be cool! But there is like 100 electrolytic capacitor in that thing, and two big ol' 12000uf 58V...
I will try to make that plan fit this driver...
Also I have been considering recapping my father old Yamaha integrated for the cornu. It would be cool! But there is like 100 electrolytic capacitor in that thing, and two big ol' 12000uf 58V...
Somewhere there is a pic of a guy who built a spiral into his floor and just elevated the platform a bit to accommodate.
X did you post that?
X did you post that?
2.25 single mouth
Hi there CC: What are the dimensions of the side sheet? Is the horn based based on a simulation for a specific diver (if so, the details would be interesting to many readers here on DIYAUDIO)? ...regards, Michael
Hi there CC: What are the dimensions of the side sheet? Is the horn based based on a simulation for a specific diver (if so, the details would be interesting to many readers here on DIYAUDIO)? ...regards, Michael
I've got a vacation coming up and am thinking about building a pair of these. I've got two Tang Band W4-1320SI laying around, waiting for another project. I'm thinking of doing the baffle in plywood and the spirals (and possibly back) of foam board. I've been trying to find it here in Sweden and I'm not sure I've succeeded. The type of foam board I can get a hold of here is of this type:
Koninklijke Moorman Karton - Foamboard lightweight boards
It seems to be much more rigid than the type used by people in this thread. Maybe it won't bend at all, scoring or no. However, it might be that it's still usable, probably being easier to cut at angles than ply (which, I guess, would be the other option).
Speaking of which, someone mentioned doing the spirals out of wood would be preferable (sound-wise) to foamboard, but of course a much bigger hassle. I'm wondering what the losses might be from doing foamboard rather than wood. I guess foam would absorb more of the energy but it seems bass is already too strong and we don't want higher frequencies escaping through the horn anyways. Just general rigidity?
Koninklijke Moorman Karton - Foamboard lightweight boards
It seems to be much more rigid than the type used by people in this thread. Maybe it won't bend at all, scoring or no. However, it might be that it's still usable, probably being easier to cut at angles than ply (which, I guess, would be the other option).
Speaking of which, someone mentioned doing the spirals out of wood would be preferable (sound-wise) to foamboard, but of course a much bigger hassle. I'm wondering what the losses might be from doing foamboard rather than wood. I guess foam would absorb more of the energy but it seems bass is already too strong and we don't want higher frequencies escaping through the horn anyways. Just general rigidity?
Moset,
Those FC boards appear to be the thick paper faced high quality variety and should work. They will bend with scoring of the inside paper face. I built a curved wall speaker cabinet with similar FC boards made by Elmer's in the US and it bends nicely. The thin $1 store stuff bends easier as the paper is very thin. You won't improve the sound much with a wood channel as you want bass frequencies and having some damping by the foam channels may actually be beneficial. The W4-1320 drivers should work well - I think Prezden made them and reports that they sound great. 24 to 27 in x 4 in deep should work.
Those FC boards appear to be the thick paper faced high quality variety and should work. They will bend with scoring of the inside paper face. I built a curved wall speaker cabinet with similar FC boards made by Elmer's in the US and it bends nicely. The thin $1 store stuff bends easier as the paper is very thin. You won't improve the sound much with a wood channel as you want bass frequencies and having some damping by the foam channels may actually be beneficial. The W4-1320 drivers should work well - I think Prezden made them and reports that they sound great. 24 to 27 in x 4 in deep should work.
Great news! I'm going to aim for about 24" - if this ends up on my living room wall, I've got a wall clock at just about that size that would sit in between them. Should look fine. The plan is to recess the driver into the baffle, so that I can pull some sort of fabric over it and have it disappear completely.
XRK,
Have you experienced with a cornu with only one horn, like a snail spiral. That way we could lower the frequency of the lowest note possible while still have a manageable speaker size??
Have you experienced with a cornu with only one horn, like a snail spiral. That way we could lower the frequency of the lowest note possible while still have a manageable speaker size??
Hey X,
Ol' buddy, ol' pal, ol' friend-o-mine, I need a favour. I have no internet right now. Shaw cable in Vancouver is shut right down so I am tethering this through someone's phone. I am getting itchy and am thinking about another Cornu. I have the Radio Shack 40-1354A drivers and I need a design. I don't have the parameters in front of me but I know they are out there. Can you find it in that kind heart of yours to set me down the right path?
TIA.
Ol' buddy, ol' pal, ol' friend-o-mine, I need a favour. I have no internet right now. Shaw cable in Vancouver is shut right down so I am tethering this through someone's phone. I am getting itchy and am thinking about another Cornu. I have the Radio Shack 40-1354A drivers and I need a design. I don't have the parameters in front of me but I know they are out there. Can you find it in that kind heart of yours to set me down the right path?
TIA.