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Old 15th December 2013, 10:21 PM   #1221
unaHm is offline unaHm  United States
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Ok, the front panel is being glued on! Hopefully in the dry Colorado climate I'll be able to test the enclosure with a speaker in a few hours!
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Old 16th December 2013, 04:53 AM   #1222
unaHm is offline unaHm  United States
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Well I couldn't resist - intrigue overtook me! I moved the first of the enclosures (the only one I've really been working on) to a room where I could test-fit one of the Aurasound drivers.

I tried the speaker first in free air to compare it before it sat in the enclosure.

The difference is impressive! I was quite surprised by the definition of the low end, and like others have said, the natural and open sound they have across the entire range of the speaker.

I didn't really notice any major lack of high frequencies either - they'd definitely work for a television room application, as my wife agreed when she heard them. She was surprised too!

I did listen to each port individually, and noticed that one of them seemed to be 'dead', so I can only guess that there's a leak somewhere. Bah!

Still, my first attempt wasn't particularly accurate in terms of consistent widths of strips of foam core. The second one I'm working on had every strip cut within the same session on my table saw, so creating a seal should be easier!
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Old 17th December 2013, 01:07 PM   #1223
xrk971 is offline xrk971  United States
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As an OT post on another thread, I just found out that Gpapag made a Cornu from a pizza box a while back.

More here:
The Nautaloss Ref Monitor

Click the image to open in full size.

Now that is some great re-purposing - very green speakers!
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Old 17th December 2013, 01:49 PM   #1224
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That's fantastic! Great stuff.

I might try to get my kinds involved in building something like this. What a great idea.

Last edited by Philosophil; 17th December 2013 at 01:51 PM.
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Old 17th December 2013, 01:55 PM   #1225
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I think Gpapag's idea is great!!!
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Old 17th December 2013, 02:02 PM   #1226
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Quote:
Originally Posted by xrk971 View Post
I would go with FF125WK as several folks have tried that with success in a 28 in class Cornu.
The 125 is rather bass heavy. It required more stuffing in the throats than other drivers and even so, some might want a tweeter with it. The next one I do, I think I will use the an old Foster 10F3. I think that box is well suited to that driver and it's clones.
Quote:
Originally Posted by xrk971 View Post
Gpapag made a Cornu from a pizza box
George, that's very creative.
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Old 17th December 2013, 07:20 PM   #1227
gpapag is online now gpapag  Greece
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I hadnít thought that these would attract some interest (besides, the pizza is gone )
The spiral is a slightly modified version of Daveís first pdf (att.1).
First I modified the flare ratio at the initiation of the spirals.
Then I decided on a rigid compression chamber behind the speaker. This is made from a paper cylinder (a section from the core of kitchen paper towel) on which I cut two slits which serve as the throat of the inner spirals.
I hand drew the spirals on A4 paper and then a photocopier enlarged it to fit the size of the pizza box.
I then glued the enlarged drawing at the inner side of the box using lipstick paper glue.
I made the box less acoustically transparent by covering both sides of the paper pack with self-adhesive transparent plastic sheet.
I cut the opening and glued the speaker flange to the box with bathroom silicon. I glued around it the compression chamber.
Then I made the spirals out of packaging paper straps. I used bathroom silicon for to fix the spiral strips over the spiral drawing.
I routed the speaker wire along one of the spiral sides and glued along itís length.
After all this silicon cured, I cut the spiral mouths at the side flappers of the box and then applying a bead of silicon on the top side of the spiral strips and around the sides of the box, I closed down the lid of the box , then the side flappers.
I trimmed the excess silicon from the sides and bundled the whole box with paper tape and put some books over the box.
Next day I removed the paper tape and let the box in open air for the siliconís acid smell to evaporate (it takes at least two days)
The 2Ē speakers are taken out from some dirty cheap(8Euro) computer active speaker units having a usb powered amplifier inside.
I played the cornus with this amplifier and it is a wonder what they manage.

Kudos to xrk971 and Cal for starting and developing the Cornu idea.

George
Attached Images
File Type: jpg 2 DSC00411.jpg (459.0 KB, 251 views)
File Type: jpg 3 DSC00412.jpg (312.4 KB, 247 views)
File Type: jpg 4 DSC00423.jpg (382.3 KB, 208 views)
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File Type: jpg 8 DSC00435.jpg (566.9 KB, 47 views)
File Type: jpg 9 DSC00437.jpg (362.0 KB, 56 views)
File Type: jpg 10 DSC00415.jpg (412.4 KB, 65 views)
Attached Files
File Type: pdf 1 Cornu-clone-spiral.pdf (13.0 KB, 10 views)
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Old 17th December 2013, 07:23 PM   #1228
gpapag is online now gpapag  Greece
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Out of curiosity, I built another pizza box project (same pizza size), this time the construction was of a closed type, the inner volume filled with pillow stuffing.
I compared the two.
Conclusion: There is no turning back.
“Pizza-box” style Cornu is a superior animal, an ideal active speaker system for a teenager’s or student’s room.
Don’t take me wrong. Cornu type speakers can be made to compete with serious speakers.
But it is the new generation that needs easy to build and decent sounding speakers, not us the old guys.
Young people need and would look for cheap, light, small, active speakers to match with their music sources -mobile phones, tablets and the likes- and speakers that take no desktop or floor space.
Cornus offer all these plus an open and balanced sound, not the screamy sound of the cheap PC speakers and flat screen TVs, they can be planned and built in a weekend and can bear the style of the one that builds them.

George
Attached Images
File Type: jpg 11 DSCN1432.JPG (360.7 KB, 78 views)
File Type: jpg 12 DSCN1433.JPG (350.9 KB, 66 views)
File Type: jpg 13 DSCN1434.JPG (370.9 KB, 68 views)
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Last edited by gpapag; 17th December 2013 at 07:30 PM.
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Old 17th December 2013, 07:40 PM   #1229
xrk971 is offline xrk971  United States
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George,
Thanks for the detailed account of how you made it out cardboard. I may have to take up the pizza box Cornu next - those drivers you have look ideal for messing with in this application. I have similar ones on these small collapsible Bluetooth speakers. It may be good to make a BT version that wirelessly syncs with a cell phone. Mono is fine and the BT speakers have a 3 watt amp I think. Use a cheap USB to wall plug dongle to power.

What are the dimensions of your pizza box and channel depth?

Last edited by xrk971; 17th December 2013 at 07:49 PM.
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Old 17th December 2013, 08:09 PM   #1230
gpapag is online now gpapag  Greece
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Internal dims:320mmx320mm, depth 35mm.
Compression chamber diameter 45mm, the two slots are each 7mmx30mm.
I haven’t used any stuffing.
The wireless idea is superb!

George

>Edit: By the way, these speaker units I used in the pizza box Cornu are ideal for diy headphones (tested!)
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Last edited by gpapag; 17th December 2013 at 08:15 PM.
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