Spherical Enclosure Considerations

[romanoaf]

Hi there, In the process of building/designing my first set of bookshelf speakers. I bought an overnight sensation kit to make it a little easier.

I've been playing around with the idea of 3d printing a spherical enclosure. Something I'm not sure of is, do the volume and porting calculations remain the same if I'm moving to a spherical design? Are there any other considerations I should make prior to printing?

Preliminary CAD I've been working on

 

[LightBit]

Port calculations and volume are the same, but you will probably get nasty resonance: http://www.diyaudio.com/forums/full-range/202189-spherical-speaker-design-help-needed.html

 

[Ron E]

Crossover may need changes. Hope you have measuring gear.

 

[norman bates]

watch standing waves.

if your sphere is 6" across inside, you may have a big peak near 1khz.
My 6" x 6" x 6" compartments had that.

 

[romanoaf]

I don't have measurement equipment. I'll likely try the spherical design out on a single speaker system. I've gone through the development papers for the BW 800 series enclosures; and adding a nautilus style tube to the sphere seems to be fully doable for me with a 3" driver and my print volume capacities.

 

[Jerms]

Sphere.... on the outside... On the inside, it needs something to break up or absorb....

If it needs a port, build it into a stand?

 

[rickmcinnis]

Everyone seems to confuse the "perfect" diffraction properties of the outside of the sphere with the MESS it would be on the inside.

I remember when I first saw those drawings in AUDIO CYCLOPEDIA ...

 

[adason]

Make it a teardrop like enclosure, sort of like B&W Nautilus...

 

[romanoaf]

I'll be working towards something like this..

 

[adason]

great...HiVi has tweeter, which already looks like it, just fix it on top...

 

[BWRX]

It sure looks pretty cool! How do you plan to build the enclosures? Any reasoning behind the size and shape of the tapered chamber?

 

[romanoaf]

It sure looks pretty cool! How do you plan to build the enclosures? Any reasoning behind the size and shape of the tapered chamber?

The design is based on the B&W 800 development papers, scaled to fit a HiVi B3N; the tapered tube on the end of the sphere is intended to reduce resonance. Nothing scientific on my end, just experimenting with what I think is interesting.

The small driver size allows me to print the enclosure in one piece on an FLM 3d Printer.

 

[googlyone]

Stuff it well with wadding. I built a spherical ikea salad bowl speaker with great success.

I have a rather significant pile of measurement gear.... with decent wadding / damping resonances were not an issue at all.

The impedance znd freq response were very very well behaved. The driver was one of the old Vidlfa premium line units - the overall performance of the enclosure really surprised me.

FYI I used
Sub woofer- 20 to 80Hz
Spherical - 80 to 3000 Hz (odd I can't remember the exact XO)
Tweeter - 3khz up.

Have fun

 

[anji12305]

Stuff it well with wadding. I built a spherical ikea salad bowl speaker with great success.


Have fun

That's clever.
Kudos

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