Yeah, I was a bit disappointed too
Hey there
I knocked up a Cornu - just the one, to check it out - but the performance didn't knock my socks off. Easy to build, and it sounded OK, but nothing more than that. Actually, that's a bit unfair; the detail was good, but, like Moset's version, there wasn't a lot of bass. And (A) I was very careful about ensuring that everything was sealed and (B) I cut the channel walls using a professional-quality Fletcher mat cutter. That's accurate to a fraction of a millimetre (say, about a 32nd of an inch), so the problem won't have been inconsistencies in the wall height. I thought it might have been the throat area, so I did some surgery on that (to increase it), but to no avail.
So I went back to a double bass reflex that I designed using Martin King's software a year or so ago, and built a couple of those. They're somewhat better. They go down to about 40Hz, the detail is clear, and the stereo imaging is better than I've achieved with any other speakers. I've designed them thin and deep, so that they sit neatly beside a couple of other cabinets, looking as unobtrusive as you could want. So I suppose I'll stick with those until the urge to build some speakers strikes me again, and I start finding fault with them...
Hey there
I knocked up a Cornu - just the one, to check it out - but the performance didn't knock my socks off. Easy to build, and it sounded OK, but nothing more than that. Actually, that's a bit unfair; the detail was good, but, like Moset's version, there wasn't a lot of bass. And (A) I was very careful about ensuring that everything was sealed and (B) I cut the channel walls using a professional-quality Fletcher mat cutter. That's accurate to a fraction of a millimetre (say, about a 32nd of an inch), so the problem won't have been inconsistencies in the wall height. I thought it might have been the throat area, so I did some surgery on that (to increase it), but to no avail.
So I went back to a double bass reflex that I designed using Martin King's software a year or so ago, and built a couple of those. They're somewhat better. They go down to about 40Hz, the detail is clear, and the stereo imaging is better than I've achieved with any other speakers. I've designed them thin and deep, so that they sit neatly beside a couple of other cabinets, looking as unobtrusive as you could want. So I suppose I'll stick with those until the urge to build some speakers strikes me again, and I start finding fault with them...
New here
Hey guys.
I've been thinking of building a cornu speaker ever since i first saw it. I read most of this thread but since English is not my mothers language and i really don't know much about theory of building speakers i'm lost in all the FS and QT and other technical vocabulary so i'm asking you guys for some help.
I want to build a 29 ¨ version. The speakers will be placed in the bathroom, so there is my first dilemma of choosing the appropriate driver due to higher levels of air moisture. Although i think this is not much of a problem since moisture levels are not that high due to the efficient ventilation system in the entire house.
I have decided to build a smooth-spiral design with two levels as the original cornu.I think it will be easier for me to build.The channel walls can be 3 mm or 7mm thick. I Was thinking of using a plywood made for bending. I already have the 3mm plywood, but i can also buy the 7mm version although this automatically raise expenses. I would really need some advice of choosing not to expensive driver and of the height of the channels for the chosen driver. The drivers price is currently set at about 50 euros per piece.No harm is done if the price is lower
I apologize if some words don't make sense but my English is not as good as i would like to be.
Any help is highly appreciated.
Thanks
Hey guys.
I've been thinking of building a cornu speaker ever since i first saw it. I read most of this thread but since English is not my mothers language and i really don't know much about theory of building speakers i'm lost in all the FS and QT and other technical vocabulary so i'm asking you guys for some help.
I want to build a 29 ¨ version. The speakers will be placed in the bathroom, so there is my first dilemma of choosing the appropriate driver due to higher levels of air moisture. Although i think this is not much of a problem since moisture levels are not that high due to the efficient ventilation system in the entire house.
I have decided to build a smooth-spiral design with two levels as the original cornu.I think it will be easier for me to build.The channel walls can be 3 mm or 7mm thick. I Was thinking of using a plywood made for bending. I already have the 3mm plywood, but i can also buy the 7mm version although this automatically raise expenses. I would really need some advice of choosing not to expensive driver and of the height of the channels for the chosen driver. The drivers price is currently set at about 50 euros per piece.No harm is done if the price is lower
I apologize if some words don't make sense but my English is not as good as i would like to be.
Any help is highly appreciated.
Thanks
Hey guys.
I've been thinking of building a cornu speaker ever since i first saw it. I read most of this thread but since English is not my mothers language and i really don't know much about theory of building speakers i'm lost in all the FS and QT and other technical vocabulary so i'm asking you guys for some help.
I want to build a 29 ¨ version. The speakers will be placed in the bathroom, so there is my first dilemma of choosing the appropriate driver due to higher levels of air moisture. Although i think this is not much of a problem since moisture levels are not that high due to the efficient ventilation system in the entire house.
I have decided to build a smooth-spiral design with two levels as the original cornu.I think it will be easier for me to build.The channel walls can be 3 mm or 7mm thick. I Was thinking of using a plywood made for bending. I already have the 3mm plywood, but i can also buy the 7mm version although this automatically raise expenses. I would really need some advice of choosing not to expensive driver and of the height of the channels for the chosen driver. The drivers price is currently set at about 50 euros per piece.No harm is done if the price is lower
I apologize if some words don't make sense but my English is not as good as i would like to be.
Any help is highly appreciated.
Thanks
Welcome aboard the Cornu train! The Faital Pro 4FE32 can work as it is a pro audio driver designed for harsh environments. I believe the paper cone has a waterproof coating and the rubber surround is better than foam. These are 91dB sensitive and have a smooth response. The neodymium motor makes it very light so can be hung from wall no problem. Make it 4.5in thick and 29in wide. I suggest you stick to the original Cornu plan with combination of square and curved channels. It is a tricky thing to modify that correctly if you are not an expert on making back loaded horns. If you want a good chance of success then use the plan and scale it - going off on your own is not advised. I have simulated the plan as drawn and it works well whereas there is no sim if you change it. Furthermore, you want the corners to filter out the high frequencies and act as an acoustical low pass filter. I don't see how a double layer is easier to make? Twice the channels and twice the chance for an air leak. As the above two posts have indicated that they don't have bass. I will remind folks that a small pinhole leak near the start of the channel will destroy the deeper bass extension. The analogy is a flute with a pinhole leak from a finger pad - the flute cannot play the lowest note unless all holes are tightly sealed.
Thanks xrk971 for such a quick response.
The Faital Pro 4FE32 seems like a reasonable driver for my pocket so i think i'll go with them.
The reason i think double layer version would be easier because the height of the channel walls are halved. Obviously there are reasons you mentioned tha are against this version.
You suggest 4,5 (115mm ) high channel walls, what about the thickness of the walls.Does it even matter if the thickness is 3,7 or even 10 mm ?
There is one workflow that is stuck in my mind due to some kind of a professional disorder since i work with milling machines.
I was thinking of stacking several mdf boards and glue them together.I would then mill the whole thing out of the box.
A depth of chanell 115/2 on each side would i think be acceptable for milling. The thickness of the channel wall would preferably be more than less due to deflecting whenn milling.
The Faital Pro 4FE32 seems like a reasonable driver for my pocket so i think i'll go with them.
The reason i think double layer version would be easier because the height of the channel walls are halved. Obviously there are reasons you mentioned tha are against this version.
You suggest 4,5 (115mm ) high channel walls, what about the thickness of the walls.Does it even matter if the thickness is 3,7 or even 10 mm ?
There is one workflow that is stuck in my mind due to some kind of a professional disorder since i work with milling machines.
I was thinking of stacking several mdf boards and glue them together.I would then mill the whole thing out of the box.
A depth of chanell 115/2 on each side would i think be acceptable for milling. The thickness of the channel wall would preferably be more than less due to deflecting whenn milling.
If you must mill due to a professional disorder
, consider milling rabbets in a spiral pattern into front and back plates, and then using bendy ply or something for the spirals. That would be much less wasteful, and it would make assembly easy.
I for one would like to do the forensics on Moset and Paul's build. Something has gone awry. I know my first build would be a bit leaky and you've read the impressions of the bass. It's staggering so I am thinking there is something else. Even the placement, which is part of the design, doesn't matter that much.
If you must mill due to a professional disorder
Yeah that's one of the ideas to. Mill slots into the front and back baffle and the bend plywood into slots.I'll sleep over till Monday. I guess at the end i'll probably go with the foam board. Tomorrow i go skiing so i guess my mind will be of cornu spiral for at least a day.I still would like to know what would be the appropriate thickness of the channel walls and if that matters much.
I laid the cornu on the floor and put some weight on the baffle over the night and it got a bit better, but nothing substantial. Eventually, I took a knife to it to try and separate the baffle. There was a lot of dried wood glue on it and looking at it now there's nothing obviously wrong (apart from the missing baffle, of course). The channels look of reasonable even width. I've reattached part of a channel that came loose when pulling the speaker apart and I've caulked along both sides of each channel on the back, to make very sure there aren't any leaks. I'll let that set and then caulk the hell out of the top of the foamcore before reattaching the baffle.
Cal: I'll get a picture up of how it looks at the moment. Maybe there's something obvious that I'm missing...
Cal: I'll get a picture up of how it looks at the moment. Maybe there's something obvious that I'm missing...
It looks good. Are those double layer channel walls? How were you able to take the baffle off so cleanly after the glue dried?
Yep, I only got hold of 3mm foamcore, so I doubled up. I glued the first ones together using wood glue but the latter are with hot glue, since it was just soo much simpler.
I got the baffle off using a knife, force and luck, I guess. I've now removed the wooden supports, to make sure they're not too long and inadvertently keep the front and back apart. I want to make sure any weight I put on it helps to even out any differences in channel width by forcing the higher parts down to a common height.
I got the baffle off using a knife, force and luck, I guess. I've now removed the wooden supports, to make sure they're not too long and inadvertently keep the front and back apart. I want to make sure any weight I put on it helps to even out any differences in channel width by forcing the higher parts down to a common height.
Well, I sealed it up yesterday evening and let it set over night. This time with sanitary silicone and without wooden supports. The result is quite a lot better. The caulk won't have hardened completely until after a couple of days, apparently, but there's no movement in the structure of the speaker - back has about 18 hours and is also hot glued, front has about 12 hours and is held in place only by the silicone. Now, depending on song, I can get close to wall-shaking action from this one, which is nice. Nice enough that I'll make sure to finish the second one as well, at least.
There was mention of a big frequency peak at around 200 Hz. Did anyone experiment with getting rid of that with a filter? I guess it would detract a bit from the cheap-and-cheerful approach of these speakers, but none of my other full-rangers are designed without them. Maybe they're just BSCs, though...
There was mention of a big frequency peak at around 200 Hz. Did anyone experiment with getting rid of that with a filter? I guess it would detract a bit from the cheap-and-cheerful approach of these speakers, but none of my other full-rangers are designed without them. Maybe they're just BSCs, though...
Attachments
great work here on these interesting speakers.
I have a an option to source either Fostex FE103EN, or FF125s and want to build a pair of these spiral Cornu speakers.
what driver/spiral dimension would give me the best results? I am pretty flexible and happy to go large if necessary.
this is for use in an apartment where the listening position will be 12" away from the speakers.
Brad
I have a an option to source either Fostex FE103EN, or FF125s and want to build a pair of these spiral Cornu speakers.
what driver/spiral dimension would give me the best results? I am pretty flexible and happy to go large if necessary.
this is for use in an apartment where the listening position will be 12" away from the speakers.
Brad
Cheers Coen,
I have a spare FE103, which is to replace a a blown driver in a friends backloaded horn that I built in 2012. I copied the Cheap Trick 164 horn and they sounded very nice indeed.
Maybe I should go with 32 inch spirals and try the FE103 first in one of them. If I find the bass lacking I could then maybe get a pair of FF125 drivers.
How deep should I build the horn? The FE103 driven builds that I have seen use a double layered horn. Would this help the LF extension.
Brad
I have a spare FE103, which is to replace a a blown driver in a friends backloaded horn that I built in 2012. I copied the Cheap Trick 164 horn and they sounded very nice indeed.
Maybe I should go with 32 inch spirals and try the FE103 first in one of them. If I find the bass lacking I could then maybe get a pair of FF125 drivers.
How deep should I build the horn? The FE103 driven builds that I have seen use a double layered horn. Would this help the LF extension.
Brad
Hi Brad,
Just a quick correction. The FF125 (4.5") drivers are in a 27". The RS 1354's (5.25") are in the 36". The 36's are mighty impressive by way of comparison. The 27's are fine but do exhibit that hump in the high bass area. I think the 103's in a 32" would be a good balance. X can suggest the channel depth.
Just a quick correction. The FF125 (4.5") drivers are in a 27". The RS 1354's (5.25") are in the 36". The 36's are mighty impressive by way of comparison. The 27's are fine but do exhibit that hump in the high bass area. I think the 103's in a 32" would be a good balance. X can suggest the channel depth.
Cheers Carl,
32 inch looks good to me. I could go for 36 inches, but may not be able to get those RS1354 drivers here in the UK.
Looks like I'm going to build front and back panels with 5.5mm weather ply and possibly use 6mm bendy mdf for the inner spiral walls and the 5.5mm ply at the openings.
Brad
32 inch looks good to me. I could go for 36 inches, but may not be able to get those RS1354 drivers here in the UK.
Looks like I'm going to build front and back panels with 5.5mm weather ply and possibly use 6mm bendy mdf for the inner spiral walls and the 5.5mm ply at the openings.
Brad