The X Board (Pure Panel) stuff looks really nice, similar to honeycomb composites used in aircraft floorboards (they are made with Kevlar and aluminum honeycomb). Looks pricey though, what does it cost for 3/4 inch panel?
As there are various thicknesses and finishes available ,it would be best to contact the suppliers to find out about the price.Alternatively,end users,such as cabinet makers and shopfitters may be able to supply off-cuts,to enable an enclosure to be constructed.Garry Cawsey,the designer of the experimental speaker,mentioned in post#30 found that the thicker panel(58mm) gave the best results as thinner walls required more bracing to meet the same performance.This was for large internal volume enclosures(200 l+).The aircraft industry certainly have come up with brilliant technology for lightweight high stiffness panels and Celestion used just such a honeycomb panel on a small speaker which showed the technique to be worthwhile..
Thanks for the link. I've not seen the polystyrene product paper faced just phenolic and polyisocyanurate.
It this stuff extruded [board] or expanded bead [popcorn], if you don't mind my asking? Looks like an interesting product.
Nice work! I have so wanted to try those but thought it would drive me crazy. And you work fast too, I like that.
Cal, Thanks. This was fun and can be fast if you mod the design to skip the middle separator panel which has to be cut through with a thin slot to hold the walls. Since the Viva TC9FD is smaller I scaled the overall depth back to 2 -3/8 in so it has a thinner profile and doesn't need the middle brace. Not having that middle let's you bend the walls and tack in place with hot melt. I was able to do each in a couple of hours. The final gluing of the top cover with white Elmer's glue is the slowest part. I can't wait to install the drivers and hang them up for a listen. I never imagined that the Cornu spiral horn project could be this fast - it is intimidating when you look at it but is really not that hard.
Regards,
xrk971
I admire both your candor and humility. You sure have given me something to think about. I have a set of the CSS VWR126's that might be just the ticket.
Creative Sound - Product Details
Creative Sound - Product Details
Those are really nice drivers, I would almost feel bad to put $126 drivers in a $3 enclosure. Maybe make at least the front and back panels out of Baltic birch plywood but use foam core for walls... the assembly would still go fast if you skip the divider, you will need to make it deeper though as these are substantially bigger than the 3.5 in dia drivers I used. Good luck!
It just occurred to me that if you use big drivers like a 5 incher, you will need the depth for the full sound. This can be done by hand tacking 2 horns on both sides of one panel with hole cutout, then gluing the tops and bottoms on to get 8 horns per speaker like the original Cornu. Still is faster than messing with a divider panel that needs the channels cut out. Also, you may need to use a masonite panel as foam core board is too small for 70 cm x 70 cm dimension.
Use the jpg image plan from here http://sebastian-pitkanen.blogspot.com/2006/07/cornu-spiral-copy-horn.html for your project, it should work as this was designed for 5 inch horn. Make the walls out of foam core board and hot melt glue to wood panels. You can bolt four corners for extra strength and maybe use 4 bolts with tubes where the speaker screws are. This sounds like fun and doable in a weekend. Have fun, let me know if you need more tips. I have not tried Ryno Board but it looks like it should work well as it is thicker and stiffer.
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I will have to source the board. It doesn't seem like it is a stocked item around here. I agree with the extra bolts where the driver is. Also, it would be nice to do it in one go rather than two horns. Two horns = twice the chance to screw it up.
Yes I will have many questions for you especially concerning technique. Your hot melt, do I read that as a hot glue gun with the whitish sticks that you put in the back? If so great, I have that, if not please explain.
Yes I will have many questions for you especially concerning technique. Your hot melt, do I read that as a hot glue gun with the whitish sticks that you put in the back? If so great, I have that, if not please explain.
Yes hot melt glue gun with sticks. I sized the horn entrance for your driver as a 1.5 in wide channel with the depth of the walls as 3 inches. This makes the Ao equal to Sd of the driver. Three inches is not too thick and you can stick with one layer of horn channels. :
I've worked with a simular product here in the states called "Gator Board".
First sound from Cornu mini horns
I just had a few minutes to listen to the Cornu mini horns after hanging them in the recreation room. I was not really expecting much because when I look at the design, it just seems too open - there are all these open channels, I mean there really isn't a box that is closed. I put on Suzanne Vega - My Favorite Plum because it has a good test of the bass response and beautiful vocals. I was absolutely blown away, I mean my jaw dropped, and I have an ear to ear grin and could not stop listening, except that I have things to do like go to work. The sound stage is amazing, and it is so open and full bodied. Just listen to me, I sound like a wine critic describing a wonderful Petit Sirah... Put it this way, I have never heard anything like this before from ANY speaker, let alone a pair of 3.5 in drivers in a foam box. Just flabbergasted. I love these spiral horns and am a true believer now. The sound output from the horns radiates in a 360 degree pattern from the edges of the thin cabinet and really makes the room feel bigger than it is, but you do not lose the imaging because of the detail from the two point source full range drivers doing their job. You can walk around and the sweet spot is rather large. I am also noticing that they are very efficient - I am only using the Lepai at half setting and the sound just fills the room.
I just had a few minutes to listen to the Cornu mini horns after hanging them in the recreation room. I was not really expecting much because when I look at the design, it just seems too open - there are all these open channels, I mean there really isn't a box that is closed. I put on Suzanne Vega - My Favorite Plum because it has a good test of the bass response and beautiful vocals. I was absolutely blown away, I mean my jaw dropped, and I have an ear to ear grin
and could not stop listening, except that I have things to do like go to work. The sound stage is amazing, and it is so open and full bodied. Just listen to me, I sound like a wine critic describing a wonderful Petit Sirah... Put it this way, I have never heard anything like this before from ANY speaker, let alone a pair of 3.5 in drivers in a foam box. Just flabbergasted. I love these spiral horns and am a true believer now. The sound output from the horns radiates in a 360 degree pattern from the edges of the thin cabinet and really makes the room feel bigger than it is, but you do not lose the imaging because of the detail from the two point source full range drivers doing their job. You can walk around and the sweet spot is rather large. I am also noticing that they are very efficient - I am only using the Lepai at half setting and the sound just fills the room.Attachments
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This Gatorboard product looks really nice with wood fiber veneer. How hard is it to cut - does it require a saw or is an X-Acto knife still sufficient? This might be the ticket for an upgraded spiral horn - now that I know the design sounds awesome.
I have some leftover Pergo "wood" laminate that seems like it would make an excellent facing for these foam projects. You can link multiple ones together to get desired width. Has anyone made speaker cabs out of this material?