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

I remember the Cronu Spiralhorns at ETF way back in 2003. I walked into the room with music playing and had to ask "where are the speakers". The guy that built them had nice silk art stretched across the fronts and it had me completely fooled since they were hanging on the wall like paintings. I asked to have some punchy music put on to see how well they play it and we had a room full of German, Dutch, Swiss and American guys up on our feet dancing to it. It was a fun moment. They are truly stealth speakers.
 
27" should be great for those X. How old are the 1197's? Ferrite or Alnico?

I think these are ferrite, circa 1999 based on the stamped label on the back. They were new in box units that I got as a gift from Godzilla. 🙂

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Kiwi Cornu update and a couple of questions

Firstly to say, that is now been almost four years since I built mine, and I still really enjoy them and play music through them pretty much every night. Amazing speakers.

I want to make them as artful and 'stealth' as possible and have decided to put a piece of thin MDF in front of them covered with digitally printed loudspeaker cloth. (see pic). This cover is the same size as the speakers (500mm x 500mm).

I now want to make some other front covers for them but make these about an inch wider on all sides so the speaker becomes even less visible than before and you really have to look at them side-on to realize that they are speakers and not paintings/art prints. Do you think that making the front cover wider will impact on the sound quality?

Second question: to get them up against the wall as closely as possible (and still have a pro finished look) I want to fit my next set with some cup shape speaker terminals (as per pics). They will protrude about 15 mm into the driver cavity and there will be a gap of 10 mm between them and the back of the VIFA driver (which protrudes about 35mm into the cavity). Any impact on sound? and if so, what can I do about it to remedy it?
 

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I think the extension of the baffle will make them sound better as you're really just extending the length of the horns. As far as the terminal goes, what percentage of the driver chamber are you using up? If it 10% or less, can't see that as a problem. Also consider than the best terminal is no terminal so if you can live with it as is...
 
I agree with Cal, but if the cup is not taking up significant room, should not be a problem. Maybe glue a piece of felt padding to cover the hard plastic cup to reduce the back reflection. Looks very nice. You could even put a wooden painting frame around it and no one will know it is a speaker.

Is this the actual speaker?

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Is a cornu design a variant of a T-line?

It seems to me that a t-line and a cornu are similar.I have started a "compact T-Line" thread on the Full Range forum and If you think so, I would like to point to this forum if you'll think it is appropriate. I have downloaded the template and printed/taped several sheets together to use a foam core frame and 3/16" heated/bendable PVC strips.

Questions:
1. In a T-line you have some harmonics/ripples that can be made smaller by putting the driver about 1/3 of the way down the tunnel: Does a cornu design need that?
2. I noticed that a cornu has four tunnels. Are they tuned to different frequencies which I would think, is a better design than a T-line - is that correct?
3. Driver: Is the best to have a driver around 80 fs and low vas?
Thanks
scott
 
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Cornu is most definitely a back loaded horn (it had about a 1:25 expansion ratio - very rarely do BLH approach this mostly 1:10 or less). There are 2 pairs of horns each with a different t length to help smooth out the ripples from the 1st reflection at the horn mouth. That's why it has so much bass "gain". It's pretty forgiving with what you use actually. I used a TC9 with high Qts.
 
Cornu is most definitely a back loaded horn (it had about a 1:25 expansion ratio - very rarely do BLH approach this mostly 1:10 or less). There are 2 pairs of horns each with a different t length to help smooth out the ripples from the 1st reflection at the horn mouth. That's why it has so much bass "gain". It's pretty forgiving with what you use actually. I used a TC9 with high Qts.

Would an Audience A3 work well in a larger one?
 
I have spent the last 7 hours reading this great cornu forum. What dedication and passion you'll have!
I posted a rather long post in another tread ( loudspeaker/full range/"Cornu vs Xrk971" that should have gone here and I don't want to double post. It basically asked XRK971 which speaker system does he like the most - the speaker in his "wall mounted theater" thread or his cornu build. As well as asking others to give me their opinions before I start the build. To the moderator, should I repost it here or can it be moved here?
Thanks
 
I think when you start your Cornu journey, you will appreciate what we all did in the beginning. My concern is that we stopped before they got big enough to appreciate their potential. I am thinking bigger is better but I am also cautious that Daniel Ceisinger (sp?) didn't pursue larger ones for whatever reason. All I know is that every time I increased the size, I had a new ***** and giggle session. I would love to try a 48"er with the appropriate driver and I know X will help me along the way. He is the key that unlocked my age old desire and gave me the opportunity to realize something I didn't think I was going to accomplish.

Maybe when there's more time.

In the meantime I will enjoy the ones I have and the other projects as well.

bonjonno, best wishes in getting your feet wet. I hope it goes well.
 
Cal, I'd love to start with a large one. But I live in a teeny tiny place and there isn't enough free wall space! Last week I started the foam bug by making a pair of mini karlsonators 0.4X. they are playing as I type and sounding grand. I have a feeling that the Cornu holds some of the magic I used to experience in 1972 listening to Hendrix thru dynaco amps and Frazier Dixielander folded horns. I'll know if there's promise if they can make a headphone sized speaker emanate bigly. That may cause me to have to add another room on the house and go large...