The Origami dipole line-source sub

[Khanate]

Suddenly I got creative. And an idea for a line-source, dipole, horny-H-baffel sub showed up in my head. The result you can see in the picture below.

It's quite large at 96x84x240 [cm] WxDxH, and 7 15" woofers.

I have not done any mathematical studies. I've just visualised my idea.

It would be interesting to read your thoughts about the design.

 

[bjorno]

Hi, This picture or your posted image cannot be opened unless you apply for a hifisentralen.no membership.

Hifisentralen

Why not post the picture here at DIYaudio and check if it can be opened?

b 🙂

 

[Khanate]

Thanks bjorno. I'll have to uploud the picture at photobucket. For some reason I'm not able to post pictures directly from my hard-drive. Unfortunately I cant acces photobucket from where I'm now. But maybe later this evening.

 

[Cal Weldon]

Posting pics:

Click 'Post Reply' and go down to 'Manage Attachments'.

 

[Khanate]

Here we go. Thanks Cal 🙂

 

[tb46]

Hi Khanate,

You might find this thread interesting: http://www.diyaudio.com/forums/multi-way/69401-bastani-prometheus-w-dipole-sub.html

Regards,

 

[63781]

Its a good idea to run the drivers in push-pull, as this reduces distortion. But then you should have 6 or 8 driver for the best effect, not 7.

Apart from that I like the idea.

 

[Khanate]

Thanks StigErik. This design just happened. I happened to start with a 15" woofer, and decided for 90 deg angles in the folded array, and 60 deg expansion horizontally. After some fiddling with the dimensions in CAD-system, I ended up with this.

The first time I encountered a folded speaker-diaphragm was in my youth when I read about the Heil-driver in the fantastic Danish magazine High-Fidelity. The way the Heil-driver pushed the air-waves, they said, was comparable to how we can shoot away a cherries-stone by pinching it with our fingers. So, accordingly, the bass of this system should be super-fast 😛 Imagine yourself being hit with coco-nuts in your belly at 344 m/s 😱

In the nearest future this is not a project I will realise. The system is way too big for my apartment. I just got an idea, and it was fun to document it with CAD. I could be tempted though to see how small I can make it with smaller woofers. Maybe an array with several 10" woofers, in the same arrangement, would give a more acceptable size.

I have no idea how the different speaker-parameters like baffle-step, cavity resonance, cancellation, the room, speaker- Qts/load/impedance/resonanse-peak etc will shape the result. But in the time of affordable sound processors, maybe it's not that much of a problem?

 

[63781]

Your design is NOT an Air Motion Transformer like the Heil, not in any way. The nearest thing we have for bass are the Tymphany LAT drivers, they work in the same way as AMT's.

Also - if you want to make something very compact, a Ripol might be more interesting. Google "ripol" and you will find a lot of info. Ripols can be stacked as tall towers.

 

[Khanate]

Sure StigErik, the Heil-analogy was just a joke 🙂 My 90 degree expansion in the "throat" is of course a lot when compared to LAT and the Ripol. But, I would guess that it gives some increase in velocity compared to a flat baffle.

Anyway, the Ripol is an intriguing design. And as a tower; even more so.

Actually I've been lurking around in this forum for a while. Reading about ripols, dipols, cardoid-dipols, OSWG and horns in general. Lots of interesting and inspiring stuff, like your own open-baffle to no-baffle tread.

 

[63781]

True - this forum is great with a lot of interesting threads. I love the fact that professionals with a lot of real knowledge are also contributing, unlike some other forums where professional people are usually banned. Not to mention hifi-forums where the general ignorance is getting worse every day......

 

[Kjeldsen]

Some measurements on a LAT 700 tower here. Maybe som inspiration
http://www.soundimage.dk/Eloquence and LAT 700/Eloquence.htm

 

[djk]

extend this taller as needed, or rotate the drivers 90°

 

[63781]

@Kjeldsen:
Very nice woofer towers! Are they usually placed that close to the rear wall and corner?

 

[Kjeldsen]

@Kjeldsen:
Very nice woofer towers! Are they usually placed that close to the rear wall and corner?

Sorry, it's not mine (see link), but from one active in danish site Hifi4all. He is former writer for former danish mag high fidelity.

My own OB's are far from finished🙁

 

[Khanate]

To be honest, I think the LAT drivers looks awful. They reminds me of the modern reinforced plastic propane/butane-containers. But the Ripole triggers my interest. I'll see if I can come up with something smart 🙂

LAT? No, just some gas. 😛

An externally hosted image should be here but it was not working when we last tested it.

 

[63781]

To be honest, I think the LAT drivers looks awful.

That's why cloth grilles were invented I guess .... 😉

 

[Khanate]

😀You're so smart

BTW: the propane-bottle won a good-design award. Probably not so with the Lat.

Anyway, since we are talking about LATs: are they any good? 🙂

 

[Dag Johansen]

Anyway, since we are talking about LATs: are they any good? 🙂

Short answer: no!🙄
They are the result of to many engineers trying to reinvent the wheel.

Dag

 

[Khanate]

Short answer: no!🙄
They are the result of to many engineers trying to reinvent the wheel.

Dag

Ha ha. Sounds like something I could have done. I like to reinvent. Wheels, speakers etc. Just for fun. And I guess I'm not alone 😀