It occurred to me that the steel hemispheres have a 3mm wall thickness rather than the 5mm I used when thinking about acrylic. That 2mm extra radius makes quite a difference in volume - 13.3 Litres for 3mm thickness vs 12.77 Litres for 5mm thickness. In this case I think I can make the partition wit...

Thanks :guiness; Are you admiring my balls :lol: The holes need tidying up as I said and enlarging by half a mm and then I need to do the other one. I tried this on one of the other balls that now have the wrong size holes in just to check it works and it all goes together very nicely. I put some sa...

I have made four holes in another 150mm diameter indestructible dog ball :grin: Blue this time. Done with a hole saw, tape measure and a few metal squares. I am very pleased with it so far, the holes are in exactly the right places and 90 deg between each hole and it's neighbours. Just needs a bit o...

Tweeter protectors for when little fingers are around :grin: https://www.avsforum.com/attachments/dynaudio-protection-tweeter-620x264-jpg.1062522/ Or this http://i.imgur.com/ERcPjUW.jpg Having been thinking about tweeter grilles I could not come up with an ideal solution which did not undo some of t...

Thanks for your input Geoff and Rex. It's always good to have some engineers around. We have a saying in agriculture - "That'll be good enough for farming" :lol: Things get fixed with the big hammer. That doesn't cut it here however. This drawing shows nearly perfectly what I have planned....

Up and down in a cube is good, I know that already as my latest prototype is exactly that. I would be nice to have a play around though.

As to stands, why not attach three legs to an oak ring then you can sit the speaker in the ring. That would be the logical thing to do. But I was getting all obsessive about having enclosures as smooth as possible because the mid bass are still producing output at 10kHz due to there being no electr...

Either design has a high centre of gravity, you need to ensure that it will remain inside the footprint of the speakers. The wider the spacing of the feet the more stable the speaker. Thanks Geoff. I did realise that. I could make the legs from solid round brass bar as I have a load of it. That wil...

Rex or Geoff, what do you think of the following that J lifted from a manufacturers website "The internal volume of the enclosure is spherical which maintains an even pressure around the rear of the driver cone so the acoustic energy at lower frequencies is preserved". Has this been trans...

Rex or Geoff, what do you think of the following that J lifted from a manufacturers website

"The internal volume of the enclosure is spherical which maintains an even pressure around the rear of the driver cone so the acoustic energy at lower frequencies is preserved".