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Ever think of building a Cornu Spiral horn? Now you can!
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Old 15th February 2019, 10:01 AM   #2571
SDJKQS is offline SDJKQS  India
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Thanks for sharing my video
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Old 17th February 2019, 10:34 PM   #2572
bonjonno is offline bonjonno  United States
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Join Date: Jun 2005
Location: Rapid City
I took advantage of the single digit temps (or less) and whipped up a couple more of these foamcore speakers. These are 28 x 4 Cornu spiral horns with Dayton PC105-4 4 drivers. Cost about $60 altogether. Used Lowe's RevolutionPly 5mm poplar plywood for the front and backs. Overall they turned out OK. There is some confusion as to what I'm hearing in the midrange on some recordings, most likely drum or percussive string sounds. I'm a big fan of the various mini Karlsonators w/TC9FD's, and have delved into high end wooden projects in the past w/Focal and ScanSpeak drivers. So it'd be nice to have clearer detail, and I may order some Tang Band W42142's to plop in these boxes. Previously I built micro Cornus (14.5 sq) w/2 drivers for my TV and they yielded outstanding results. I knew ahead of time that these are not reference monitors but should result in some big wow factor. A surprise was working with the RevolutionPly instead of all foamcore. Even tho I picked a very good specimen 4x8 out of the stack at Lowes, the material exhibited waviness and buckling, especially when attaching the second piece (back). I was simply unprepeared for that and didn't have the necessary number of small heavy weights or dozens of large clamps necessary to combat this. The first speaker came out OK but the second was a mess and had lots of large air gaps after the glue dried. Hopefully they were all near the edges so I could fill in the gaps. All four horns seem to be transmitting OK tho one was a bit weaker than the others. That said, there is no lacking of bass in these things. It was a wonderful way to fill up a subzero week. Only sliced my finger once and then took time off to build an apple pie Also threw a loaf of bread in there for some variety. Thanks to everyone who tried these and talked about their experiences especially Cal and X. I posted a YouTube with a variety of short music clips that I'm prone to listen to and one w/ vocals that we recorded here locally with people I regularly work with. It was recorded on a portable Tascam that has built in X-Y mics. Everything on the recorder is flat but it yielded a bassier sound than what was experienced in the listening room. There is very minor adjustment to the eq in my computer, maybe 3 bands and nothing changed more than 2dB. So these speakers turned out surprisingly flat.
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Old 18th February 2019, 05:43 AM   #2573
xrk971 is offline xrk971  United States
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Ever think of building a Cornu Spiral horn? Now you can!
Hi Bonjonno,
I loved your video! Nice production and what a great way to share the journey of making the Cornu's. I see the Karlsonator's have a big role in your sound system too. Your Cornu's sound excellent - I have never heard the new Dayton's before so it looks like they might be a good choice for a lot of projects. You are a baker too! Winter is a great time to make bread and nothing makes the house smell better. It looks like you really made this on your kitchen counter.
Thanks for sharing,

Qts of 0.51 is a nice figure for a $10 driver. This would be great for a MLTL or in a Karlsonator too.

XRKaudio https://www.etsy.com/shop/XRKAudio

Last edited by xrk971; 18th February 2019 at 05:46 AM.
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Old 18th February 2019, 01:17 PM   #2574
PJN is offline PJN  United States
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Join Date: Dec 2004
Location: Pa, USA
Hi Bonjono,

You might want to try stuffing your cornus with Dacron pillow stuffing to attenuate the sound. I did with my pair and way able to clean up the mid-range and control excess bass/boominess. Stuff the horn sections and area behind the drivers to taste.

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Old 19th February 2019, 01:45 AM   #2575
bonjonno is offline bonjonno  United States
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Join Date: Jun 2005
Location: Rapid City
DOH! I subscribed to this thread but didn't get any notification you guys replied. Thanks X for ur kind words, you have been a total inspiration for these projects. Down to one piece of apple pie I have connected the 28" Cornu and XKiClops together and have listened to the combo for 12 hours or so and they sound great together. It could be that the Cornus are breaking in a bit and smoothing out a little. PJN thanks for the tip. In fact, I forgot to stuff b4 gluing on the back. Forgot twice!! One of the perks of getting old. I use dacron from old pillows because it's usually on hand and goes a long way. So, I pushed some into the two channels of the throat as far as I could, stuffed the speaker box- did this b4 first screwing the driver on, and put two good fistfuls in each horn mouth to taste while the music was playing. The big wads in the horn mouths really cured the boominess. It's cool you suggested exactly what I already did, affirmation that it's a good move.
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Old 22nd February 2019, 08:03 AM   #2576
Doctor Why is offline Doctor Why  Germany
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Default Damping

Hey guys,

I even had to use some damping material in my Monster Spiral Horn to reduce a weak peak at ~ 75 Hz - although the horn is only operated from about 30 Hz to about 60 Hz.

A 20cm ball of rather tightly pressed and laced BAF wool just behind the two drivers was enough.

Careful attenuation of horns with broadband speakers is therefore even more important.

LG Doc
My Rig: DIY Backloaded Horns with Magnet-modified Fostex FE206en + Modified S.M.S.L. SA98 + Source Thinkpad T430 w. USB Soundcard + Synology 32TB NAS
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