Hybrid OB / Horn project

[iansr]

Quite a while back I posted about this speaker project. For reasons I won’t trouble you with, I’ve not been able to progress things, but in a few months I’ll be in a position to set things up so I’m now looking to finalise the design. The speaker is centred around Joseph Crowe’s ES290 biradial horns that Steve made for me. If needed, I have some Fostex T925A bullet tweeters to handle the upper end, but I’ll try the speakers with and without these.

To cover the FR up to the horn at c.500hz, I have 4 (sic ) x AE Dipole 12 woofers per side. My current focus is on how I configure these 4 woofers.
Steve recently brought Bert Doppenberg’s Sigma to my attention and I’m thinking about the possibility of cloning the woofer section albeit with 4 woofers rather than 6. I’ll post some pics of the Sigma once I’ve remembered how to do it!

[iansr]

[iansr]

I’d welcome comments about the Sigma woofer system, or indeed any other suggestions re the 4 woofers.

(My original plan was a vertical stack - WW/HORN/WW - but that would be 2m tall and that is too tall for my liking.)

[vinylnvalves]

That 3D cad image confirms it’s a slot loaded open baffle, Bert has just used the wings as wave guides. As long as the chamber is very small the 1/3 and 1/5 wave length modes will hopefully be above 500 Hz, may need a higher order xover to mitigate them, also allow you to cross the horn a little lower. Scott probably could suggest the best way of modelling it in Hornresp.

The bathroom board off cuts I have got could make the guides. A nice marble effect.
Seriously to others - it’s phenolic decorative finish 10mm birch ply, but is fully water proof. The cost of a full sheet is 2/3’s that of bulk standard birch ply.

[iansr]

Steve
How would you bend those boards - kerf?