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

[xrk971]

That’s what they said about Sd when I scaled the FH3 for a 3.5in driver. A few years later, the FH3 lite came out for 3.5in drivers and guess what, it was the same size as the one I scaled based on Sd. It’s a good place to start and can always be optimized by modeling. But sometimes it works quite well.

Homage to FH3 scaled by Sd:
FH3-inspired Foam Core Mini Build

FH3 Lite:
Frugel-Horn Lite for 3" drivers

 

[Lingwendil]

Hey X, how do you think that those PA130-ish MCM 5" drivers we grabbed from Newark would work in a cornu? I was thinking that a 24x3 might be a good starting point...

 

[xrk971]

Probably work well. They are 5.25in drivers so maybe 32in actually would be needed to work. Nominal is 4in and 28in.

 

[Lingwendil]

Hmmmm. Do you think you could do a sim? I'm trying to figure if I want to do a pair in either a cornu or a Karlsonator first. I really want to do a cornu, and already have a pair of Karlsonator anyway, so if I end up running a separate HF driver I would rather do it for the cornu.

 

[xrk971]

I think the smallest Cornu that can take the MCM 55-1595 is a 30in edge. However, this driver has such a high Qts, it seems to produce quite a bass overshoot peak. But it might sound pretty fun given how much coloration there is.

This is a 30in x 4in deep Cornu:

 

[malthe]

This is the 5F/8422T01 simulated in a 35.5 cm x 4 cm cornu. Why is the whole thing dropping 12dB after the ~ 900Hz – ?

 

[Doctor Why]

Due to Qes= 0.69 may be a little weak for higher Frequencies in a Horn ?

 

[planet10]

Sims don’t tell you much when you ar eabove th emass corner… i.e. 900 Hz is way above where the sim is accurate.

dave

 

[haraldkasper]

Question

i havent time to go throug all the pages anybody knowing what pages thew plans are

 

[Karl71]

Lowther DX55 in a Cornu?

How well would it work?

 

[planet10]

Original Cornu was for an 8” Lowther.

dave

 

[Karl71]

Would it work in the contemporary DIY versions? That should have been my question.

 

[xrk971]

I thought original Cornu was FE108EZ? An 8in driver would make for a huge Cornu. Base size is about 28in on an edge and 5.5in deep.

 

[Karl71]

Yes, originally it was. Digging a little into the Cornu sites, I did find reference (in German) to a very large Cornu with an eight inch Lowther, and a pic of it.

I can’t link because I’m using my tablet.

 

[planet10]

dave

 

[Karl71]

Thanks, Dave. That’s the pic.

Now, if that could be done with a DX55...

 

[Lingwendil]

If anybody needs help resizing their plans to work with different sizes, I found that this site will make a multipage PDF of the plans for you, and then you just need to trim and fit them together.

Wall art generator - Rasterbator

I went to print out plans at work, and since all of our corporate devices run Chrome OS, and don't have Acrobat or similar, they just use the Google suite of office type tools. Without a more advanced program I found it a bit tricky to impossible to tile pages. Using the Rasterbater online tool, I now have printed up plans for 20", 24", and 28" cornu builds taped together and ready to use.

Of course, you will have to play with your printer settings, but it was pretty simple to get it all going for me.

Time to dig out my extra pair of TC9s, and some black foamcore to start laying out a pair of front/back panels

 

[Karl71]

Lingwendil -

Thanks very much!

I haven’t heard of the DX55 being used in a Cornu. I wonder why, since there is precious little out there in terms of cabinets.

 

[Karl71]

Xrk971 -

Do you think any dimension needs to be changed to accommodate the DX55?

 

[xrk971]

I would have to run simulation if you want exact scaling needed for DX55.