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Old 11th July 2013, 06:13 PM   #961
prezden is offline prezden  Canada
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Thanks guys- I have to find someplace in Canada where I can the bluetooth modules- The shipping from parts express is more than double the cost of the modules. Mouser have these: How do I wire them up?

SPBT2632C1A.AT2 STMicroelectronics | Mouser
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Old 11th July 2013, 08:48 PM   #962
xrk971 is online now xrk971  United States
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Prez,
Not the same thing. That looks like a BT comm module for digital data only. Like wifi. You need one with audio output.
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Old 11th July 2013, 08:59 PM   #963
prezden is offline prezden  Canada
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Thanks x- that's what I thought. It's weird that none of the Canadian suppliers carry them
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Old 12th July 2013, 03:34 AM   #964
xrk971 is online now xrk971  United States
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Default Big Budget Cornu (BBC) that Packs a Punch!

OK, I have been messing around with modeling speakers way too long and not getting to do any actual building speakers. It's making me pretty antsy... I have what I think is a pretty cost effective design for a Big Budget Cornu (BBC) that packs a punch.

The idea is this, how can one build a speaker that can throw a decent 90+ dB (50 Hz to 100 Hz) bass shelf at least 3 meters away on 1 watt for as little $ as possible.

The design I have come up with uses the $3.60 Aurasound NS525 driver that has been successfully used in the DNA horn. The Madisound Speaker Store

Match that to a 36 in x 4 in deep Cornu spiral horn, fitted with a simple conical front horn that goes from 12.5 cm x 12.5 cm throat to 23 cm x 23 cm throat with a 10 cm depth.

I am thinking that the front and back panels can be made from two sheets of 4 ft x 8 ft x 1/8 in thick luaun plywood ($12 ea). The channels and front horn will require about 6 sheets of 30x20 in foam core ($6).

So we are at $15 for drivers (with shipping), $24 for plywood, $6 for foam core, maybe $5 hot melt sticks. Total cost is $50. But here is what you get:

First plot is frequency response at 3 m with 1 watt. Second plot is impedance. Third plot is cone displacement.

This is perfect for a low power tube amp, a 5 watt Nelson Pass single ended class A ACA, etc.

Any takers? This will probably be my next project once I get back in build mode.

Make no mistake, this is a BIG speaker with 9 square feet of baffle. But it mounts on a wall and is relatively thin. The sound will be BIG with little power driving it.

Have fun.
Attached Images
File Type: png Cornu-36in-NS525-Freq-3m.png (31.1 KB, 541 views)
File Type: png Cornu-36in-NS525-Impedance.png (24.8 KB, 401 views)
File Type: png Cornu-36in-NS525-Displ.png (25.6 KB, 402 views)

Last edited by xrk971; 12th July 2013 at 03:40 AM.
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Old 23rd July 2013, 10:45 AM   #965
petervr is offline petervr  New Zealand
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Default Kiwi Cornu

I'm pretty late to the Cornu party, but then again only found this site a few weeks ago.

I have some AN Super 8's that I want to put into an enclosure but after having read about the Cornu's I thought I'd give those a go first.

This being my very first project, I thought I'd play it safe in order to avoid disappointment and go for a straight copycat of X's first one: 20" X 20" with the Vifa TC9FD18. So I got those ordered and had them shipped over here ($40 for shipping..., but have little options in that regard).

After they arrived I hooked up the Vifa's and let them break in for a while as my regular stereo speakers. The sound was pretty much what you could expect from just a little 3.5" driver sitting on the mantelpiece on their own: not much..
Anyway, I glued up one speaker last night and have mounted the driver tonight and started listening to it:

I'm very pleasantly surprised at the change: This speaker sounds very nice with very nice bass (to my untrained ears anyway). Quite amazing what this little thing can do once its in the enclosure!

Now on to glue and mount the second one and hopefully have them both going tomorrow night!

For the build I used foam core for the horn channels and 4.75mm MDF for the face and back, since the price of foam core and MDF is pretty much the same over here and I didn't want to buy more than 1 sheet of FC (32 x 40).

A stack of left over terracotta floor tiles came in very handy for clamping the speakers, as you can see from one the pics.

So, all up this has been a very rewarding first project with a good outcome.
Thanks xrk971 and all the other contributors.

Now thinking about a full size Karlsonator for my AN8's ...

Attached are a few pics of the build.
Attached Images
File Type: jpg base_layout.JPG (507.2 KB, 336 views)
File Type: jpg base_spiral.JPG (556.9 KB, 331 views)
File Type: jpg base_spiral2.JPG (515.1 KB, 104 views)
File Type: jpg glueing_top3.jpg (150.4 KB, 93 views)
File Type: jpg completed_1.JPG (587.1 KB, 98 views)
File Type: jpg completed_3.JPG (517.3 KB, 91 views)
File Type: jpg completed_2.JPG (569.3 KB, 86 views)
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Old 23rd July 2013, 11:16 AM   #966
xrk971 is online now xrk971  United States
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Peterv,
Wow! Congratulations on a great build! It looks like you built a copy of the very first Cornu I made based on the modified channel paths that I used with the squared angular internal passages in the first part. I am happy to hear that the sound is pleasing. It's a fun little speaker and a unique conversation piece when friends come over.
Looking forward to seeing what you do with the AN 8.

Regards,
X
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Old 23rd July 2013, 04:39 PM   #967
prezden is offline prezden  Canada
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Very nicely done
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Old 23rd July 2013, 08:45 PM   #968
petervr is offline petervr  New Zealand
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Quote:
Originally Posted by prezden View Post
Very nicely done
Thanks prezden. All that I need to do now is finish them off with some cool art prints like the ones you have on yours!
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Old 23rd July 2013, 09:03 PM   #969
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I have build my FC Cornu a while ago and put i a side. Why? well i tried different kinds of glue to glue to glue the two parts together but again and again with the same results it lets go on the edges and leaked. So since you have a successful build which glue or kind of glue did you use? i am sure it is already been answered somewhere but could not find it.
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Old 23rd July 2013, 09:12 PM   #970
petervr is offline petervr  New Zealand
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Quote:
Originally Posted by Xerxes75 View Post
I have build my FC Cornu a while ago and put i a side. Why? well i tried different kinds of glue to glue to glue the two parts together but again and again with the same results it lets go on the edges and leaked. So since you have a successful build which glue or kind of glue did you use? i am sure it is already been answered somewhere but could not find it.
Goeienavond.

I used Gorilla wood glue. It is polyurethane based and foams up around the edges hence sealing the gaps.

Hope that helps.

groeten

Peter V
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File Type: jpg Gorilla_wood_glue.jpg (65.4 KB, 77 views)
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