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

[xrk971]

Originally Posted by Zigis

How thick is foam board you use? I see few different thickness in shop.
How many boards go to pair of mini or micro? Difficult to understand total length of strips.

how about thous small silver drivers, used in many small Logitech, like this;
Amazon.com: Logitech Stereo Speakers Z120, USB Powered (980-000524): Electronics

I see in local computer shops $10 pair speakers with same drivers, I don't know for sure, they are 2" or even little smaller.

It is 3/16 inch thick - if There is a Dollartree in Latvia, they have only one thickness. The z120 you suggest would even be better than the s120's I used. The strips you cut as you need but for the micro it was like about 8 x 30 in long strips. You need to join them in segments, can't have one that is long enough. It takes about 3 sheets of 20 x 30 in sheets for the micro, and 6 sheets for the mini including faces. Let me know how the z120s are mounted, if tbere is no flange with screw holes you will have to glue it in place and that is a bummer as you can't tweak and adjust the stuffing.

[Pano]

Cal, why don't you add Dave's scalable PDF to the first post?

[xrk971]

Originally Posted by gpapag

When I’ll manage to get back home, this "bug" will be my first speaker experiment in 2013.

My complements to the inventor, xrk971 and you.

George

George,
Thank you for the kind words but the inventor is Daniel Ciesinger, I am just a guy who likes to make things in a hurry and am handy with a hot melt glue gun I think I showed folks that it is possible to make a good sounding speaker without having to use heavy dead sounding MDF, or having to spend countless hours in the workshop to leave a speakerwidow behind. When building speakers doesn't require a tablesaw, a router, a drill press, or a shop vac, I am all for it. It was borne out of necessity because at the moment I don't have access to power tools or a shop, so I had to keep myself busy somehow. I think there are a lot of DIY'ers out there in a similar situation whether they live in a small apartment, or just don't yet have a workshop, that shouldn't stop them from making or trying out new speaker designs.
Regards,
Xrk971

[freax]

I wonder what a speaker made out of coconut would sound like, specifically coir: http://en.wikipedia.org/wiki/Coir

[xrk971]

Coir is a fiber and would probably work well as stuffing in a speaker. The coconut shell, however, would probably make an excellent speaker cabinet as it is spherical and you would minimize diffraction or baffle step effects. A 6 or 7 in dia coconut would probably be suitable as a HT speaker with a 3 in FR driver in a sealed coconut cabinet stuffed with coir It would really look good if your HT room was decorated with an island theme!

[jacco vermeulen]

Originally Posted by Cal Weldon

catch the bug.

Cal,

I appear to have, despite my dislike of horns, all thanks to you.
(maybe because it's not a folded horn, not a single horn exit opening/location, Hey ! And so flat)

Any reason for using use the FF125WK, instead of Mr Ciesinger's FE108E Sigma, other than half cost and availability ?

(and don't believe everything Mr Papageorgiou writes)

[quinnling]

I've been following the spiral concept through various posts on different thread and through Google searches. Conceptually it is a really elegant idea !
I have a few questions.

1. Is there any math behind it to scale to different drivers(Lowthers). On my searches I did find a person who used a Lowther Driver.

2. How much Low frequency enhancement will this horn will support ?

As crazy Idea ... How feasible is it to mount a front horn to it ? Since the speaker is a nice square ...For inspiration, maybe a horn similar this (post 54) Can be grafted to the spiral back loaded horn ? :
I want these 12" field coil on ebay


To bad I just started a different horn project .. this seems very interesting

[Cal Weldon]

Originally Posted by jacco vermeulen

Any reason for using use the FF125WK,

Yes, they were sitting on a shelf downstairs just begging to be put in a box.

Mr Ciesinger's

Thank you for spotting that, spelling corrected. So is xrk971.

[mondogenerator]

I fancy trying the micro version as i have a couple of types of 2 inch drivers. Is there a preferred range of Qts that will work best in the micro cornu?

[xrk971]

Originally Posted by quinnling

I've been following the spiral concept through various posts on different thread and through Google searches. Conceptually it is a really elegant idea !
I have a few questions.

1. Is there any math behind it to scale to different drivers(Lowthers). On my searches I did find a person who used a Lowther Driver.

2. How much Low frequency enhancement will this horn will support ?

As crazy Idea ... How feasible is it to mount a front horn to it ? Since the speaker is a nice square ...For inspiration, maybe a horn similar this (post 54) Can be grafted to the spiral back loaded horn ? :
I want these 12" field coil on ebay


To bad I just started a different horn project .. this seems very interesting

If you go back to the foam core thread, there are several posts by Don Hills whom is modeling this on Akabak, he also gives an outline of how to design one from scratch with the driver of your choice. So, I think you can design this for Lowthers. I think this horn will make an alredy efficient driver even more efficient. One of the things that the Cornu has is very high efficiency of horn output.

Regarding the front horn: Yes - in fact, Cornu (the company making these) offers wooden 8-segnment horns that can be strapped to the front of the driver. I look at this and see perfect opportunity to make the front horn out of foam core board too - and you could make it perfectly curved rather than use flat segments.

The bass or low frequency enhancement question has been asked severral times before. All I (and Cal) can say is that it has a huge impact based on listening to it. I was fiddling with the cable mounting hardware on the back of the Cornucopya yesterday while it was still playing music, and flipped it on its face on the carpeted floor and I still heard a significant amount of music coming out of the edges through the horns (mid bass, low bass, and actually quite a bit of highs - which is not unexpected given how there are few sharp corners to act as low pass filters). This gave me an idea of an easy way to demonstrate how significant the horn output is. Flip it on its face on carpet so all sound comes from horns - record this with good mic to mp3. Flip it around and record sound with both, and post this so you all can listen for yourselves. Note that this is very different than how it sounds on a wall as the ceiling and floor interaction is important. But it will give an A/B test of the difference with and without front driver output.