Thanks, sorry for the late reply. It's still the FE103EN
did the speaker cloth like carl recommended, just hot glued it on and finished it with a wood trim. But as you can see, there is still space on the wall for a bigger pair...
Soldermizer ready to make ***/2 attempt at cornu...
Hi! I am at post #991 (Sept. 2013) in this thread and may read your replies within a week or two
I want to try my hand (which is all thumbs) at a variant of a spiral horn. To meet my low standards it shall be:
1. Very easy.
2. Using only the cheapest supplies.
3. Probably have inferior performance.
What I want to attempt will not be a true Cornu or multi-horn but rather I propose a simple spiral single horn. I have a supply of (free) coroplast signs. The largests are 24x26" so I will aim for a 24" square horn. I want to try the following drive (I bought 4 of them as they should work as Bose 901 drivers too.)
GRS 4FR-8 Full-Range 4-1/2" Speaker Pioneer Type A11EC80-02F 8 Ohm
Some questions: I am competent with Hornresp so I modelled this driver as a BLH and get decent results. I gather, but didn't see in detail ("yet"?) whether the Cornu design uses multiple horns to smooth out the inevitable peaks and dips of a horn. This is what I understand it does. But to model these more complex designs, does one need Akabak? Can it be faked in Hornresp somehow?
For the spiral itself: I don't have access to curve plotting software and while I perhaps studied the math, that was decades ago and it is well forgotten
Could I do the following: since in Hornresp it is usually recommended to model parabolic, could I just "wing it" and let the spiral expand linearly? If I am just using one spiral, can't I just measure as I go?
I propose the name for my project as "cornu-copulate" because I am bound to f---k it up
Hi! I am at post #991 (Sept. 2013) in this thread and may read your replies within a week or two
I want to try my hand (which is all thumbs) at a variant of a spiral horn. To meet my low standards it shall be:
1. Very easy.
2. Using only the cheapest supplies.
3. Probably have inferior performance.
What I want to attempt will not be a true Cornu or multi-horn but rather I propose a simple spiral single horn. I have a supply of (free) coroplast signs. The largests are 24x26" so I will aim for a 24" square horn. I want to try the following drive (I bought 4 of them as they should work as Bose 901 drivers too.)
GRS 4FR-8 Full-Range 4-1/2" Speaker Pioneer Type A11EC80-02F 8 Ohm
Some questions: I am competent with Hornresp so I modelled this driver as a BLH and get decent results. I gather, but didn't see in detail ("yet"?) whether the Cornu design uses multiple horns to smooth out the inevitable peaks and dips of a horn. This is what I understand it does. But to model these more complex designs, does one need Akabak? Can it be faked in Hornresp somehow?
For the spiral itself: I don't have access to curve plotting software and while I perhaps studied the math, that was decades ago and it is well forgotten
Could I do the following: since in Hornresp it is usually recommended to model parabolic, could I just "wing it" and let the spiral expand linearly? If I am just using one spiral, can't I just measure as I go?
I propose the name for my project as "cornu-copulate" because I am bound to f---k it up
Soldermizer,
There is a Cornu Akabak script provide by Don Hills early on in this thread. If you know how to use Akabak, it should not be hard to use. The Cornu indeed uses 4 horns with 2 of different lengths to smooth the response and that type of topology can only be done in Akabak or more advanced 3d simulation software. You can't fake it in HR, but in your case if doing a single spiral, you don't have to as HR models a single horn path very well.
Just note that although the Cornu as presented here in this thread looks complicated to make, it is not. Indeed it is one of the easiest and potentially cheapest diy builds you can do. Since you live in the US, I would suggest a visit to your local Dollar Tree (or similar) and pick up $5 worth of foam core to play with. It will be much easier to work with and use the Cornu scaled pdf drawing for your driver. Since you want to use the GRS 4FR driver, I can sim that for you but based on experience, I can guess that a 24 in x 24 in x 4 in deep Cornu will work fine. You may have to play with the driver chamber to make room for the basket and magnet. Starting on your own design from scratch is commendable but you may be setting yourself up for a less than ideal experience. If you follow the instructions on the regular Cornu with foam core and a hot melt glue gun, you will be rewarded with a great sounding, unique speaker that is EASY to build. Trust us on this.
Cheers and good luck!
X
There is a Cornu Akabak script provide by Don Hills early on in this thread. If you know how to use Akabak, it should not be hard to use. The Cornu indeed uses 4 horns with 2 of different lengths to smooth the response and that type of topology can only be done in Akabak or more advanced 3d simulation software. You can't fake it in HR, but in your case if doing a single spiral, you don't have to as HR models a single horn path very well.
Just note that although the Cornu as presented here in this thread looks complicated to make, it is not. Indeed it is one of the easiest and potentially cheapest diy builds you can do. Since you live in the US, I would suggest a visit to your local Dollar Tree (or similar) and pick up $5 worth of foam core to play with. It will be much easier to work with and use the Cornu scaled pdf drawing for your driver. Since you want to use the GRS 4FR driver, I can sim that for you but based on experience, I can guess that a 24 in x 24 in x 4 in deep Cornu will work fine. You may have to play with the driver chamber to make room for the basket and magnet. Starting on your own design from scratch is commendable but you may be setting yourself up for a less than ideal experience. If you follow the instructions on the regular Cornu with foam core and a hot melt glue gun, you will be rewarded with a great sounding, unique speaker that is EASY to build. Trust us on this.
Cheers and good luck!
X
I'm not sure if I reported, but I finished my thin plywood 4in bamboo drivers cornus a while ago, and have been just listening to them. I like them!
I mean they're finished functionally, but not yet done with the looks. Big dilemma, leave them natural wood finish, cover them with fabric...
I mean they're finished functionally, but not yet done with the looks. Big dilemma, leave them natural wood finish, cover them with fabric...
Thanks for the words of wisdom. Even though my initial results are likely to be sub standard*, I have begun "practicing" upon my supply of coroplast boards. Just to perfect my measuring skills (greatly in need of -- even the legendary "gap-filling" quality of PU quails at the sight of my jagged peaks), as well as hot glueing and Gorilla Glue-ing. For the record, while not the "go to" material, coroplast seems to be quite sturdy, is available for free along roadsides, takes the above adhesives easily. It's also corrogated every few mm so no scoring is needed
If it weren't for experimenters like me, there would not be as many failed subwoofer cabinets destined for fires. At least with FC it's easier to dispose of the evidence and the odds of making the enclosure too big to remove from the room is less, but that is a confession for another thread
* For gosh sakes, I am contemplating using not even a REAL Bose 901 driver, but a possible surrogate with even worse specs
If it weren't for experimenters like me, there would not be as many failed subwoofer cabinets destined for fires. At least with FC it's easier to dispose of the evidence and the odds of making the enclosure too big to remove from the room is less, but that is a confession for another thread
* For gosh sakes, I am contemplating using not even a REAL Bose 901 driver, but a possible surrogate with even worse specs
I never said it is not the go to material - seems like a good option especially around areas where they stick a bizillion new construction housing signs by the roadside. Or right around election season when all the candidates for congress stick another bizillion signs along Hwy 50 in VA.
The corrugation seems like a good feature for curves and spiral channels.
Or right around election season when all the candidates for congress stick another bizillion signs along Hwy 50 in VA.
Then it is not for free... you have paid for it dearly!!!
I don't have drivers in hand and months away from starting anything (even getting the drivers) but the SB Acoustics SB65 caught my eye. How would these look in a Cornu horn? What sort of extension could be expected? I was actually looking of these for a boom box but the high frequency response extension greater than 10K and relatively good bass output (for the size) seems like it could be a really good fit for a Cornu based on the models I've seen in the thread so far.
Size is less of a concern than depth for where these would be positioned (on wall overlooking dining area of kitchen). Kitchen isn't huge but a 2.5" driver might not fill the kitchen area (~15x30 ft, speakers on the 15' section). I should stress that these would be for casual listening with people sitting directly under the speakers (nearfield perhaps not ideal for summing port and speaker output) to 25 ft away at the sink. Any suggestions for a larger full range driver that could be put in a shallow Cornu? Seems like most 4-5" or greater full range drivers I've seen posted require a depth >4". The wall they would reside on is a high traffic area so points to the 2.5" driver for making a shallow depth possible. Plywood/hardboard baffle is not an issue if >24" is justified, mostly concerned about depth at this point.
Still brain storming ideas. Perhaps a foam core cornu computer speaker -rebuild will be in my nearer future to test how the design would work in the space. Also, speaking of boom box, has anyone built a deck-friendly, portable kickstand style cornu? More ideas than time or money at the moment I'm afraid.
Size is less of a concern than depth for where these would be positioned (on wall overlooking dining area of kitchen). Kitchen isn't huge but a 2.5" driver might not fill the kitchen area (~15x30 ft, speakers on the 15' section). I should stress that these would be for casual listening with people sitting directly under the speakers (nearfield perhaps not ideal for summing port and speaker output) to 25 ft away at the sink. Any suggestions for a larger full range driver that could be put in a shallow Cornu? Seems like most 4-5" or greater full range drivers I've seen posted require a depth >4". The wall they would reside on is a high traffic area so points to the 2.5" driver for making a shallow depth possible. Plywood/hardboard baffle is not an issue if >24" is justified, mostly concerned about depth at this point.
Still brain storming ideas. Perhaps a foam core cornu computer speaker -rebuild will be in my nearer future to test how the design would work in the space. Also, speaking of boom box, has anyone built a deck-friendly, portable kickstand style cornu? More ideas than time or money at the moment I'm afraid.
I'm caught up with the thread finally!
xrk971, first let me tell you you survived a close call! Just within the past week I was in your area (and my former home)...driving south from visiting relatives in Bethesda MD among other places. You are lucky I don't know where you live because I would have demanded a guided tour
It's amazing how I can move nearly 1000 miles south and not much changes: I am still about 20 miles west of US301 and have traded US50 for (Florida) SR50
I withdraw my prior approval of glue with coroplast: my test sample (the Cornucopulate) has a partial separation. So further testing is needed.
Already mentioned earlier: with a clear or translucent front, one can put in pretty lights. Why not something like those 1970s "color organs"? I haven't seen those yet but I am sure they exist. Meanwhile for about $12 you can buy a 5 meter string of LED lights with wireless remote such as this one:
http://www.aliexpress.com/item/Disc...er-Adapter-only-RGB-Changeable/714570758.html
xrk971, first let me tell you you survived a close call! Just within the past week I was in your area (and my former home)...driving south from visiting relatives in Bethesda MD among other places. You are lucky I don't know where you live because I would have demanded a guided tour
It's amazing how I can move nearly 1000 miles south and not much changes: I am still about 20 miles west of US301 and have traded US50 for (Florida) SR50
I withdraw my prior approval of glue with coroplast: my test sample (the Cornucopulate) has a partial separation. So further testing is needed.
Already mentioned earlier: with a clear or translucent front, one can put in pretty lights. Why not something like those 1970s "color organs"? I haven't seen those yet but I am sure they exist. Meanwhile for about $12 you can buy a 5 meter string of LED lights with wireless remote such as this one:
http://www.aliexpress.com/item/Disc...er-Adapter-only-RGB-Changeable/714570758.html
Some corrections: "glue" = "hot glue"; I still like the coroplast for practice. There truly is an abundant supply of it here in FL. And the election is still a month away. Obviously you aren't going to get any blank using my scrounging methods, but on the other hand it is probably paintable, if you don't want "Joe Blow for Mosquito Control Commissioner" or "Sinkholes-R-US New Homes" signs as "modern art" hanging upon your wall
I apologize if this has already been asked before or discussed. Is it possible to elongate the design of the cornu? I am not well versed in horns or speaker design... I was looking at my TV and thought it would look cool If once wrapped in a silk or fabric it could look like an art piece. And I would be a hero in the area of WAF.