The Spheres 2.0

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Sorry, for whatever reason my first page didn't save after I was done.

So I retyped it...heres what I added

Well I was pretty impressed with my first version. So I decided to try it again, and make something a little different (although the first ones were different to say the least J.
This version will be a little more versatile. I plan on making a two way with a tear drop enclosure for the tweeter and a traditional enclosure for a 4"-7" woofer.

So far I've narrowed the tweeter selection down a bit. Most likely a Vifa. Due to cost I've narrowed it to D27TG-35-06, MG27TG39-04, or DX25TG05-04. I like the last two, especially the last one. However they are both 4 ohm drivers, so I may go with the first one. I would really like to use the XT (ring radiator) line, but those sorta expensive. The PL27TG-35-06 also looks good too.

Woofer selection is still out, but most likely it will go into a 0.55 CuFt enclosure, so that at least gets me down the right track.

Crossover will most likely be a 2K-2500 12db or 24db affair.
 
Well my previous version had around 1.1L of air space, with the 3" driver I used there it goes down to about 150Hz. Certainly not alot of bass, but I never claimer other wise.

This new enclosure has probably a little more than double that volume, however it will be used for a tweeter this time. So it doesn't matter nearly as much.

As far as physical limitations, no ones been able to give me a clear idea of baffle step characteristics in a zero baffle situation. I think some have compared it to mounting on the end of a cylinder.

So far the first versions sound pretty good to me (for what they are).
 
Because baffle step is a rather messy thing because its not just the speaker but the speaker room interaction normal bafflestep comp for a box probaby isnt perfect.
Either way it cannot be more then a 6dB drop unless some cancellation occurs which I doubt would.

Id make a line level bafflestep compensation circuit thats variable and adjust things till it sounded the best. I think id just choose 3 or 6db depending on room placement and "tune" it like you would for a box. For a perfectly flat anechoic situation this may not give flat results, but in a room where the interactions are messed up anyway I doubt that its as important.

At the end of the day BSC is applied to stop a speaker sounding thin and unpleasent to listen to.

Either way they look great :) I think that other speaker uses a scan speak tweeter and a visaton titanium midbass. LOL i bet ill find that out if i click the link.

Nice work Matt
 
Nice work hybrid!!!!! ;)
Good to see someone venturing into curvy and more exotic designs.

I think Cloth's suggestion has a lot of merit - the Seas coax is well designed and has some interesting advantages - it also eliminates baffle diffraction problems you may still have with the edge of the box and the tweeter (based on the images on your site) ...

I was looking at B&W's paper on the design of their Nautilus speakers with a similar shape, they have a detailed PDF with a lot of good info on the design, including why they used a sphere and an inverted horn ... a very interesting read!

B&W technical paper on the signature series

If you used the Seas Coax driver, you could then add a pair of biamped woofers in the main cabinet and I think you would get more output and clarity that way.

There is a Seas tweeter (25TFFN/G) with a small neodymium magnet that has no face plate (similar to those car speakers) that you could use for a tweeter section just like B&W - worth considering though I dont' know how good it is ...

I think the advantages of a sphere enclosure are just as applicable for mid as for a tweeter and in particular if you design the mid enclosure to kill the back wave with the inverted horn design.
 
Some more progress

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



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



I know some of don't like this design...maybe its because big companies use it, maybe because it screams IKEA. But this is purely an exercise in creativity for me, I'm not claiming that it does anything for the sound. It hasn't sounded bad...yet, but it has been a real learning experience.

Thanks for looking and sharing.
 
Very nice work. I don't quite see the connection with Ikea though. As far as people not liking it, I imagine they must be pretty fussy, it's quite an impressive looking project you have.

I'm a little surprised about your comments on it not sounding better. I would expect at the least that the cabinet would be more inert and thus more accurate. There is also less scope for baffle diffraction problems, although these comments apply more to your previous design with the fullrange driver in the sphere.

It's quite an inventive idea to take already curved parts and combine them, I had never considered that.
 
Hybrid,

What about the Vifa MG13? (if you want the yellow look)
or is that too big?

Why do you want to cross so high? The off axis response of the mid becomes poor if you cross too high.

For the woofer section I'd be thinking beyond a rectilinear box, but at the same time you don't want to overdo the curvy aspect. Some of the B&W Nautilus speakers might provide you with some inspiration.
 
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