Ever think of building a Cornu Spiral horn? Now you can!

I made a mistake with the price of the alpair 10 gen 3, instead of $200 a pair they where $200 a piece :( But i found someone who was selling his gen 2 so i ended up getting those, picked them up this morning :D Hope they'll be as good as the gen 3, the ts parameters do differ a little:

Alpair 10 Gen. 2 information:

T/S date LMS V4 Anechoic:
Revc= 7.200 Ohm
Fo= 35.386 Hz
Sd= 88.250 cm²
Vas= 28.119 Ltr
Cms= 2.543m M/N
Mmd= 7.480 g
Mms= 7.956 g
BL= 5.606 T·M
Qms= 2.530
Qes= 0.41
Qts= 0.35
Levc= 93.626u H
No= 0.297 %
SPLo= 87 dB
X max= 8.5-mm (1 way)
Power = 35 watts nom. 70 Max
Coil = 25-mm alu body with rectangle copper winding.

Anyhow, time to get some ply :)
 

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Founder of XSA-Labs
Joined 2012
Paid Member
I don't really get it. If there's enough bass with a single layer cornu, why make it double?

The splitter on the original is there for construction reasons: it forms the guide channel for fitting the curved wooden pieces before they are glued. Using the hot melt and flexible foam core channel negates this. Having a splitter will make the acoustic mouth size of each horn smaller, and theoretically, this may affect the lowest notes that come out.

If I were to do double layer it would be for acoustic reasons of spreading the resonances of each horn length over different frequencies for a smoother output. Taken to an extreme, you could end up with something like this: http://www.diyaudio.com/forums/full-range/236779-panpipe-pentahorn-blh-speaker.html
 
Haven't you made that thing already? i remember you posting the design in this thread waaaay back :) I didn't know it was just for construction reasons.. kinda disappointing. I was thinking it would function a bit like a multicell horn. Altough i'm not sure what the advantages of those are.
 

iko

Ex-Moderator
Joined 2008
Just borrowing from the panpipe idea, to have different horns on the second layer. :D

It would even be easy to add a layer to my current cornus. Just make a hole in the back and add spirals, and one more wall at the back. I'd do it if it promised to be an improvement. Would be nice to see some simulations of it.
 
Founder of XSA-Labs
Joined 2012
Paid Member
I was thinking it would function a bit like a multicell horn. Altough i'm not sure what the advantages of those are.

Multicell is for mids/HF's to control directivity - for bass horn you want the channel to be big to support a larger wavelength in the lateral direction.

No, I never made a double layer... There are a few folks who did though, one was a huge 3 ft x 4 ft one for an 8 inch driver. I forget who did it now. Deep back in the thread. Francisco Perez did a 2 layer out of wood just like the real Cornu. That's about it. Oh, and then there is the Cornu I saw here where it is obvious that FC was used but with wooden faces and made pretty big to fit a 6.5 inch Lowther (whomever made this gorgeous speaker, please tell us more about it! :) ) :

An externally hosted image should be here but it was not working when we last tested it.
 
Founder of XSA-Labs
Joined 2012
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Some Japanese for sale site:

lowtherÕÏ°å - À×Êϵ¨»ú - ´¨ÓåµØÇø - µ¨ÒÕÐùÒôÏì²ÄÁÏÍø ÒôÏì|½»Ò×|µç×Ó¹Ü|µ¨»ú|µ¨»úÍøÕ¾|µ¨»úÂÛ̳|µ¨»ú²ÄÁÏ|Êä³öÅ£|±äѹÆ÷|µçÔ´Å£|µç×è|µçÈÝ

Translation says it took 3 men to carry these up the stairs and embed them in the wall! Those wood baffles are thick and having 3 sheets of what appears to be solid mahogany or cherry wood of approx 100 cm x 100 cm size (that is 3.5 ft x 3.5ft) (estimated based on overal dia of Lowther which is 22.5cm) is no laughing matter.
 
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