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Old 11th December 2012, 10:28 PM   #591
iko is offline iko  Canada
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I've played around with the simulation and things change quite a lot with a few changes in the horn definition (number of horn segments or segment area). At this point I don't trust this simulation but I'll trust an spl measurement. Cal, are you equipped for such a thing?
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Old 12th December 2012, 12:41 AM   #592
Zigis is offline Zigis  Latvia
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Quote:
Originally Posted by Cal Weldon View Post
To do the trace, I used one of those tiny Philips screw drivers and made about 100 pokes per divider. When the paper was removed it was easy to follow and do the trace but as xrk said, make sure you do one spiral at a time.
Anyone know, are copying paper used in old typewriters are still available in thees days?
With this job would be much simpler.
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Old 12th December 2012, 12:50 AM   #593
xrk971 is offline xrk971  United States
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Carbon paper. Easy to poke holes with pen and then trace. Cal is already saving time by printing enlargement, I actually enlarged by hand with grid technique. You can always make carbon paper by rubbing charcoal on paper. The plan is not that hard to draw once dots are there.
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Old 12th December 2012, 01:24 AM   #594
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i know its no Cornu, but still foam core. heres my box 98% finished still waiting on the little chip amp to arrive from china. totally shoulda bought a few at $3.50 each...

its a thin marine carpet in the mouth, helps to attenuate the midbass frequencies.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

and a short vid off my phone for XRK

20121211_193632.mp4 video by klampykixx | Photobucket


on a different note, if im considering making a pair of cornu's to house a 6x9 car speaker each, i really need to pick a speaker thats brighter sounding yes? otherwise its gonna end up bassy as anything and otherwise dull? i really need to measure the specs of my drivers... alpine are hopeless... they emailed me back and dont have the spec on any of the lower class drivers..
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Old 12th December 2012, 01:43 AM   #595
Zigis is offline Zigis  Latvia
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I mean put the carbon paper on foam core board or wood panel, then put paper with spiral drawing on top, then just redraw spiral with pen, with little pushing.
Spiral is copied on board perfectly, without holes in paper.

I use this technique as a child, using for drawing copy
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Old 12th December 2012, 02:10 AM   #596
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Yes, that will work well.
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Old 12th December 2012, 02:46 AM   #597
xrk971 is offline xrk971  United States
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Klampy,
Nice job with the quad driver single mouth horn! I like the carpet treatment, very pro audio touring crew look. I can't seem to see the vid - it just goes to a photobucket page and nothing happens. No biggie.
Xrk971
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Old 12th December 2012, 03:12 AM   #598
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klampykixx,
I pondered producing an AkAbak model for your design, it's quite complex - a combination of tapped horn and back-loaded horn. Do you have T-S parameters for the drivers?

I've also considered a "Bose Wave Radio" design, with two small front facing full-range drivers. One has a relatively small sealed enclosure behind, the other has a back-loaded horn. Having only one driver with a horn allows a longer horn (therefore deeper bass) in a given space. It works, even with the tiny drivers, because the listening distance for a clock radio is usually only a couple of feet.

It would be a perfect candidate for building with 1/8" foam board for the internal walls. it could be used with an iPhone or similar providing the "clock radio" functions. The horn path could be "serpentine", like yours, or a Cornu-type spiral but reversed - spiral inwards, rather than outwards, with an exit through a hole in the centre of the bottom plate. The whole thing would be supported on feet so that the gap between the bottom plate and the table-top would form the final expansion of the horn. (This expansion can be set to any desired rate by filling in part of the space.) And finally, because the (white) foam board is somewhat translucent, you could fit internal LED lights to make it into a night light...

Run it off a small plug pack supply, add a signal-operated switch (senses the audio signal, turns on a MOSFET to supply power to the amp and LEDs).
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Old 12th December 2012, 03:27 AM   #599
xrk971 is offline xrk971  United States
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Don Hills,
I like your reverse spiral horn clock radio. I think the old Bose gen 1 had only a serpentine path on 1 driver and they went to 2 on later generations exiting a single common port like Klampy's. Are you thinking 2 in drivers or 3 inchers? The TB W3 881si for $10 ea comes to mind.... The led's with auto mosfet is a really good idea too. Do you have a schematic for that? I just had a thought, if the spirals are relatively thin, stack two one fires up and the other down, or they could both fire to common down port?
Xrk971

Last edited by xrk971; 12th December 2012 at 03:29 AM.
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Old 12th December 2012, 03:55 AM   #600
6L6 is offline 6L6  United States
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Quote:
Originally Posted by xrk971 View Post
6L6, You have some really nice curves
Lol.


Quote:
Is the black stuff the same as the Dollar Store white foam core? It looks really nice and thick facing paper.
It's the same junky stuff from the dollar store, just black. But it is easy to work with! I actually decided not to use the sheet of 'good' foamcore because it will be much harder to bend.

Also, a bit of PVA in the scores once the hot glue is set is making the curves much more solid.


Quote:
Did you power up the first one with a driver yet?
I don't have a face on it. I need a tube of liquid nails.
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