Cornu horn built as a sub. Crazy idea?

[Brisso57]

I just came across the "Cornu horn" design.
There's an interesting description and review on 6Moons. Google to find it.
It occurs to me that it'd be dead easy to build a sub by this method. It'd be downward-firing. (You could build it to be a stealth coffee table!)

The only thing you'd need would be to rout a spiral trench in the top & bottom baffle, then just use some suitably flexible material for the "walls". Glue up, paint, & bingo!

Comments on feasibility:rolleyes: ?

Doug

[Harry72]

A lot of effort... just for a sub.

[SilentButDeadly]

Someone has already beaten you too it....

http://sebastian-pitkanen.blogspot.com/2006/07/cornu-spiral-copy-horn.html

http://photos1.blogger.com/blogger/2655/67/400/middle-plate-lacquered.jpg

[Harry72]

But its not a sub, its a fullrange single driver cab!

[SilentButDeadly]

Yep.....http://www.6moons.com/audioreviews/cornu/cornu.html

[Petebass]

What you really want is a "Bill Fitzmaurice" coffee table sub. It's a true folded horn and a true sub. He sells you the designs and detailed plans, you build them yourself, then finish it in whatever looks good in your living room.

http://www.billfitzmaurice.com/TT.html

[soundman]

That looks like one of those.... "BUT" WHY designs.

If you want a subwoofer coffee table there are lots opf simple designs that will knock your socks off.
A good simple bass reflex enclosure with a good low frequency driver would doo the job real nice.

if you want to get fancy a compound design or a band pass.


crokey you should be able to get 100 to 150 litres out of a coffee table no problems.

cheers

[Petebass]

You're talking to a guy who's home theatre sub is a sealed 2x10 and who's bass guitar rig is a ported 2x12, both of which I designed/built myself, and both of which kick ass...........

Yeah Bill's designs are a bit of overkill, but he is very passionate about his folded horns.He'll argue that a horn is way more efficient (louder) and goes lower than a bass reflex cab using the same driver. He argues that bass reflex isn't so common because they're better, but because they're easier and cheaper to manufacture. Horns are labour intensive to build and therefore cost a lot more to produce, making it harder to sell them commercially for profit. He's also quick to point out that brands like EAW and Meyer all feature horns in their high end product range.

The science is sound. To quote Bill, "A Bass reflex cab is a high impedance devices operating into a low impedance load (air), and that makes for an inefficient power transfer. A horn acts like a transformer, allowing the driver to operate into a higher impedance load, in so doing improving the power transfer from the amp to the air. Horns don't have to be huge to work, and even a small degree of horn loading can significantly improve performance. Schroeder bass guitar cabs do just that".

One of these days I'll build one of his cabs just for kicks.............

[soundman]

I was talking about that thing up in post 3.
I do recognise that there are speaker designs out there that are designed purely for the ammusement of the builder:D :D :D

cheers

[soundman]

Just thinking....... isn't it about time we saw a revival of the "corner horn".

Was a very popular design in the 50's & 60's.
Basicaly you had a folded re-enterant horn design that fired into the corner of the room the walls then completed the last stage of the horn.

Jensen I think were one of the pioneers but there were quite a few others.
Klipsh also had some medium sized HIFI horn designs.

I would have my doubts. of some of these olad designs having the realy loww balls that are currently expected.

cheers

[noodle_snacks]

I have personally built a few hornloaded subwoofer designs. they do work well, but be aware that most reasonably sized designs are comprimised, unless used in groups of four or so (this does include bill fitzmaurice designs), or used corner firing etc. Two horn subs i have built with $100ea jaycar venom drivers (2 total), and three sheets of MDF outperform a 340 litre, ported, adire tempest EBS ($365 plus shipping) subwoofer i have in sound quality (a bit better), and output (about 15db better).

[billrule]

The Klipsch La Scalas were the big corner horns that were often used in cinemas; they were pretty good gear, and operated to close to full efficiency on only 20W RMS if memory serves.

[GourmetSaint]

I have also built a table sub http://www.gourmetsaint.com.au/Subwoofer

Cheers,

Mark

[Petebass]

I have also built a table sub http://www.gourmetsaint.com.au/Subwoofer

Cheers,

MarkDid you use a glass top as per the one pictured on this website?

[Harry72]

Mark what happens if one of those drivers die, I cant see how you'd access it?

[soundman]

you would usualy have a hatch in the side directyl opposite the driver.

Thats how just about every bent horn I've ever seen get loaded.

the early clipsh la scala did only have a small power driver... like evrything about that time... but they did release a concert version in the eighty's/ nineties.. that had modern high power drivers in them.

The original altec 201 cainet had a pair of 50 watt 515 drivers in them & they stood 8 feet high and three feet wide...... lots of people put higher power drivers in them later .... including altec..... I think the last of the 515 drivers were rated at 250 watts.

Anybody want some 210 cabinets.... I know where there are some:D

remember 8 feet high, 3 feet wide and about 4 feet deep.... each side is a sheet of ply.... no bent horns here... open front loaded horn with bass porting.

cheers

[GourmetSaint]

That is my sub pictured on my site. I had the 15mm glass top cut to order with a cutout for the vol/xover controls.

[GourmetSaint]

The glass is sitting on a rubber "gasket" and stuck down with a rubber adhesive used for car windscreen installations. The glass top can be removed for any "maintenance". The drivers are mounted in on a removeable panel which is attached from behind. See the drawing on the website. The seal peels of and new sealer is used to reattach.

[MrFixIt]

crokey you should be able to get 100 to 150 litres out of a coffee table no problems.

The amount of litres is not really relevant UNLESS the specific design calls for such a size. You can obtain fantastic bass from very small boxes eg 25-30 litres.

[GourmetSaint]

I agree. The volume of the two sealed chambers where the drivers are were calculated according to the t/s parameters of the 10" drivers which came out to just over 30 litres each.

[Harry72]

Yup modern sub design's have miniaturized the big boxes of yesteryear.
The 10" Kicker square sub in my car only needs 20ltrs sealed, starts rolling off at 45Hz... and being in a hatchback the resonance starts boosting around 50Hz, she's pretty well flat down too 30Hz(tested).

[soundman]

Very true that many of the bass cabinet designs these days are very compact.
But there is a price to be paid....... efficiency.

lots of the hifi drivers I see these days have efficiencies in the 80db/W at 1 metre range..... 89 is considered sensitive..... a good pro driver or a hi fi driver of some time ago would have a sensitivity in the high nineties, perhaps breaking the 100.

This is why alll these huge amps are needed these days.

add to that the other price to be paid.... high frequency resoponse.
Most of these modern bass drivers have such heavy cones coverd in so much dope that you are flat out getting 1Khz oyt of them
so you ahve to have your three way system with a sub as as well.

100 to 120 litres is a good sized box for a traditional 12" hi fi driver or a pro 15".
I have a design that takes two 400 watt ( rms real ones) 15 inch drivers, that goes 220 litres and gets to -3db @ 35 Hz, with a sensitivity arround 95db/watt at 1m. two of these is plenty for 250 seat at tables room.
and it will run two way to a large format horn crossed at 2KHz if thats waht you want.

Half that design would go into a 110 litre coffee table quite nicely. stick 200watts up its tail & that will be enough bottom end for most mortals.

Yep 100 to 150 litres is very relivent.







if you are serious.

cheers

[Harry72]

" But there is a price to be paid....... efficiency."

Yup, thats why there's 350wrms driving the car sub:D, the amp has a "2gauge welding cable" for power directly from the battery(120amp fuse at the battery incase of an accident))
Efficiency is easier to get around in a home/car environment... totally opposite to Prosound.

" Most of these modern bass drivers have such heavy cones coverd in so much dope that you are flat out getting 1Khz oyt of them
so you ahve to have your three way system with a sub as as well."

Yup#2, although a decent 2 way optimised to run with a sub works good... hopefully needing only a low order Xover between them!