Ez spherical 2-way
Started with street light globes. 16" in size they cost just $23 a piece.
Using my throat as an oscillator I sang a "frequency sweep" into the globes and could hear two nasty peaks. the lower peak made the ball vibrate, I could feel it in my hands holding it, and the higher peak was internal resonance from the ball diameter.
I coated the inside with mortar concrete, 25 lbs. in each speaker. the enclosure doesn't vibrate even when hit hard with a mallet. this eliminated the lower peak.
Then I squeezed "Ultratouch denim insulation" used for home construction. the specs of this material (STC and NRC) are the best, and you get a lifetime supply for $65.
This eliminated the higher peak.
The MDF ring is glued using "Apoxie" epoxy filler.
It takes one Saturday to make both.
The ring is cut for Seas M15CH002, and the tweeter will be mounted on a 3" plastic ball (3d printed) just above it.
Started with street light globes. 16" in size they cost just $23 a piece.
Using my throat as an oscillator I sang a "frequency sweep" into the globes and could hear two nasty peaks. the lower peak made the ball vibrate, I could feel it in my hands holding it, and the higher peak was internal resonance from the ball diameter.
I coated the inside with mortar concrete, 25 lbs. in each speaker. the enclosure doesn't vibrate even when hit hard with a mallet. this eliminated the lower peak.
Then I squeezed "Ultratouch denim insulation" used for home construction. the specs of this material (STC and NRC) are the best, and you get a lifetime supply for $65.
This eliminated the higher peak.
The MDF ring is glued using "Apoxie" epoxy filler.
It takes one Saturday to make both.
The ring is cut for Seas M15CH002, and the tweeter will be mounted on a 3" plastic ball (3d printed) just above it.
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