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

Blaides,
Nice going there - I know how it is to finish a speaker at night when all is asleep. You won't be disappointed. Looking forward to some pics.
Re the PS for the amp: 12 volt can work fine if you don't need the full 40 watts. You can use an old laptop 19 volt brick SMPS - 3.5 amp is enough for most uses. They can be ordered new for circa $8 (Amazon, NewEgg, etc). Probably different online retailer in UK. I just got my Ybdz 2.0 tpa3116d2 from Aliexpress yesterday. It was cheap at $13.50 ea but took 2 months to get. Sounds great though. I am using a 19v 3.54 amp SMPS from my last laptop.
X

Thanks X.

I've already got an old laptop powerbrick rated for 19V/4.74A, one benefit of working in IT :), the issue I have is finding a DC socket rated for 19V operation :(.

My TPA3116 came direct from Yuan Jing, it arrived in less than 7 days (it was posted on the 11th and arrived on the 15th) using their cheapest airmail delivery, faster than some of my recent Amazon orders :p.
 
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Are you talking about the DC socket that goes on the barrel shaped jack from the laptop brick? Those are I think 5.5 mm standard jacks - unless you have a Dell or Fujitsu ps which uses funny larger dia jacks. There is nothing special about 19v and 5 amps for jacks - should be able to order it. YJ probably even sells it. I just cut the jack off and wire directly to the board's screw terminal. I don't turn my amps off ever.
 
Are you talking about the DC socket that goes on the barrel shaped jack from the laptop brick? Those are I think 5.5 mm standard jacks - unless you have a Dell or Fujitsu ps which uses funny larger dia jacks. There is nothing special about 19v and 5 amps for jacks - should be able to order it. YJ probably even sells it. I just cut the jack off and wire directly to the board's screw terminal. I don't turn my amps off ever.

Yes it's the socket for the power supply to connect to, the one I have has a standard 2.5mm centre. I would butcher the supply and wire it direct to the board but I might need it for a laptop in future :).

I was just not sure of running a part rated for 12V/5A at 19V/5A, but I might just grab one of these dc-skt-dual-2-1-2-5mm-solder-dc10l and give it a bash. Plus being 2.1/2.5mm compatible means it'll enable me to use a different supply if the one I have gives up the ghost.
 
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They are different length paths that start from a common throat and channel. Then there is a bifurcation on the paths and one is longer than the other. You can do this by laying a piece of string along the paths of the PDF plan. IIRC the paths are about 1.5 m and 2.2 m for the 75 cm case. The two horn lengths help to produce a smoother horn output, albeit, still lumpy by regular monitor speaker standards striving for flatness. However, the peaks seam to land in all the right places and the coloration is not objectionable for most music.
 

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Having lived with my completed Cornus for a few days I'm beginning to suspect that I haven't got the stuffing quite right :(.

For the most part things sound good, but on some tracks that I know well you get the bass/rhythm and the vocals but the mids seem recessed and almost missing.

I assume I'll need to add more stuffing to the channels, as the driver chamber is already pretty densely stuffed, time to find an old wire coat hanger or something similar to help me push some stuffing further into the channels :rolleyes:.
 
I'm beginning to suspect that I haven't got the stuffing quite right :(.
To be expected. The initial shine wears off: "Wow that's a lot of bass!" to "What happened to the vocals?"
Yes, it takes a little trial and error (or a measurement mic) to get the stuffing right to balance the mids with the bass. Probably add some stuffing to first 3 or 4 inches of throat to channel before the split. Some success has also been achieved by adding stuffing loosely through the mouth.
Couldn't have said it better.
 
I have one speaker done yesterday but no time to hook it up yet, this weekend it looks like I will have time to finish the other one - however I will not have the patience to wait for the second one to be complete before signal is given the first one :cheers:
The build is by any standard fairly crude but it's main objective was to satisfy my curiousity with the Cornu design and the Vifa TC9 element :rolleyes:
I put stuffing in just past to where the channel splits in two.

My intention for these is to use them in my gym at home where they will fit nicely up on the wall :) Pics will follow...
 
Cal dislikes measurements for two reasons.

1. It can make me want to dislike a speaker I previously liked because it measures poorly and vice versa.

2. It tells me my ears are different from others, so my taste in a speaker's sound is somehow flawed.
Great words Cal, same reason I dislike measurements. Plus I just don't want to lay out the cash, and If my ears like what I'm hearing that is all that matters. Is it what others hear? IDK, do I care? not really they don't have to live with the system. :)
 
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