Faital 3FE22
Thanks sirs,
For the work it takes to do the cornu I'm going to buy some transducers, without experiments, and go on a fixed shot, I've been looking at the Faital 3FE22 as recommended by xrk971 for the 24" cornu, I can buy them in France for € 52.67 the couple, now comes the question , I have seen that there are 4Ω, 8Ω and 16Ω, which one should I buy? thanks
Un saludo
Roberto
Thanks sirs,
For the work it takes to do the cornu I'm going to buy some transducers, without experiments, and go on a fixed shot, I've been looking at the Faital 3FE22 as recommended by xrk971 for the 24" cornu, I can buy them in France for € 52.67 the couple, now comes the question , I have seen that there are 4Ω, 8Ω and 16Ω, which one should I buy? thanks
Un saludo
Roberto
If using regular home hifi amps, then 8ohms is the best choice. If using car audio amps with 12v supplies, then 4ohms. I would make it slightly bigger at 25in x 25in and 2.5in deep. That will ensure that there is enough room for the basket to fit in the chamber and it won't hurt as far as deeper bass goes.
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While this is true, not everyone has a perfect assembly area. So the wood you pick for the fronts is kept away from the work area to preserve it while the rears are laid down on the bench to do the bulk of the work, with little thought about the consequences.
If you simply flip your template over when laying out the second box you have best of both worlds.
The idea of making the 24 "cornu is to cut the four tops of a 4'x8 'plywood board and reduce the cost, the inner thickness would be 3.5" (this point is still not clear if the measure is proportional to the size of the box or to the measure of the transducer, I keep reading ...)
In any case, as far as I am reading the project, I find it very interesting and seductive, it can fit very well in my room, so perhaps the economic issue goes to the background and prioritizes the optimal measurements and transducer. Is the original drawing 74x74 cm and 10 cm thick by the length of the horns ideal?
Another question, I have seen that the original cornu and some DIY have a central board that protrudes a little more than the front and rear covers is due to an acoustic or constructive issue? Does it provide any acoustic improvement?
My idea is to open the grooves of the covers so that the horns go through and look at the front, making contrast, I want to put wengue veneer in front and laminate the horns with white wood, 5 sheets of 0.8mm = 4 mm in the press , glued with epoxy. I want the soul of the box to appear outside.
They are ideas…
In any case, as far as I am reading the project, I find it very interesting and seductive, it can fit very well in my room, so perhaps the economic issue goes to the background and prioritizes the optimal measurements and transducer. Is the original drawing 74x74 cm and 10 cm thick by the length of the horns ideal?
Another question, I have seen that the original cornu and some DIY have a central board that protrudes a little more than the front and rear covers is due to an acoustic or constructive issue? Does it provide any acoustic improvement?
My idea is to open the grooves of the covers so that the horns go through and look at the front, making contrast, I want to put wengue veneer in front and laminate the horns with white wood, 5 sheets of 0.8mm = 4 mm in the press , glued with epoxy. I want the soul of the box to appear outside.
They are ideas…
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What do you all think of the Cornucoffea omni speaker? I have thought about making this for a few years. The size and weight discourages me though. It would be one cool conversation piece and the bass would be earth shaking. Might want to remove coffee from the coffee table before playing too loudly.
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Theory Question
A cornu has 2 sets of 2 expanded horn lines, one set is about 50% longer than the other.
A transmission enclosure has one line that can be tapered, straight or (expanded but not used often.)
What would the result in sound be if the same overall size cornu was used with the same line lengths but the center was expanded and the isthmus (opening) was tapered to about the same csa as is now at the center?
Basically, a square tapered transmission line enclosure with two different wave lengths possibly resulting in higher spl at two different bass frequencies.
Another variation, just for testing, could be to use an existing cornu and place identical driverrs at each opening and place a mic at the cornu center to see where the spl bass peaks would be. Would that give a good indication if one of those speakers was used in the center abeit, lower overall spl but maybe close to the same bass peaks?
thanks
A cornu has 2 sets of 2 expanded horn lines, one set is about 50% longer than the other.
A transmission enclosure has one line that can be tapered, straight or (expanded but not used often.)
What would the result in sound be if the same overall size cornu was used with the same line lengths but the center was expanded and the isthmus (opening) was tapered to about the same csa as is now at the center?
Basically, a square tapered transmission line enclosure with two different wave lengths possibly resulting in higher spl at two different bass frequencies.
Another variation, just for testing, could be to use an existing cornu and place identical driverrs at each opening and place a mic at the cornu center to see where the spl bass peaks would be. Would that give a good indication if one of those speakers was used in the center abeit, lower overall spl but maybe close to the same bass peaks?
thanks
The same modelers work. It is an expanding quarter wave pipe with a bifurcation part way along to convert 2 to 4.
I would classify the cornu in the larger class of TL space that was opened up with King's (& Augspurger’s) modelers, followed by others.
dave
You mean a dual (each 2x) tapered TL of different lengths, spiral wrapped with common center chamber?
It is fairly easy to model in Akabak, and something similar was done in the Panpipe thread.
The PANPIPE (Pentahorn) BLH Speaker
DBLH
Although these were back loaded horns, the profile could be changed to be a tapered TL.
One thing to note that in a BLH with a driver rear chamber that has a constriction, the boundary condition for the horn length starts at the constricted throat. Now, with a quad tapered TL with a large center chamber (call it the seastar's body as an analogy) the boundary condition for the TL would be the terminus of one TL to the terminus of any one of the other 4 TL's (the seastar's arms), and hence the TL length would be effectively doubled but in parallel among many possible 6 different interaction paths. This would have the effect of bring the tuning frequency much lower and spread out the bumps and peaks - but the doubled lenght might be perhaps too low for the fs of the driver and associated TS parameters to work effectively. What this means is that a detailed simulation needs to be made to optimize the TL taper, length, central chamber volume, etc. But I think it can make the speaker box generally small for the same tuning in bass. Give me a week and I will see if I can come up with something in Akabak. Btw, I am not sure other simulation programs can handle a complex arbitrary length N-connected TL's.
Interesting idea though. One of the claims in the Cornu patent was exactly this, use as a tapered TL.
Btw, anyone even remotely interested in making one of these coffee tables?
A wooden salad bowl from Ikea might be a good omni refelctor.
An externally hosted image should be here but it was not working when we last tested it.
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Maybe need to use one of those waterproof polycone drivers, then some beer would not matter. I never even thought about the candy bowl use!
The curved conic like in the Sausalito Audio Works (SAW) would be interesting, tune it to project up a bit.
BeoLab 5 speakers:
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The Sausalito reflects and refracts, the ball diffracts.
Waves, not beams of light(wavelengths of light are many orders of magnitude shorter, so we rarely perceive the effects of wave propagation with light).
Squeak is right, the ball is cute, but mainly helps our 'hearing with our eyes'.
Waves, not beams of light(wavelengths of light are many orders of magnitude shorter, so we rarely perceive the effects of wave propagation with light).
Squeak is right, the ball is cute, but mainly helps our 'hearing with our eyes'.
