Here are some preliminary Shiva-X designs. We are working our way through all the drivers, producing 3D CAD designs with a cut-list showing exact dimensions anyone can copy. The Shiva-X is first on the list.
Here is the first ported design. This is about 4.3 cubic foot internal, 100% fill and a single 4" flared port. All cabinet sides are standard 3/4" MDF stock. The first design is both our smallest and least expensive to build. The port can go on front or rear and I'll have drawings for both.
Here is the output with 200W of input power. My in-room response assumes the sub placed in one of the front corners, with room dimensions (8.5' H x 21' D x 14' W) with the listening position 2/3 the way back from the front wall. I also simulate it with the rear wall missing to account for a subwoofer placed in a house where the room is open to other areas. The simulated measurement is normalized to 1M and 1/6th octave smoothed.
The black line is the simulated in-room response, the dotted blue line the anechoic radiating into 4Pi space response.
A couple notes on this. The single 4" flared port is the first thing to limit output. You can push this design into port compression and eventually chuffing at about 300W of input power with a 17Hz subsonic filter. Why not design it with a larger port? Well.... we do in the next design but that requires a larger box with more area and a larger (more expensive) amp. This design can work good with a 250W or 300W plate amp making it a very cost effective high-output subwoofer.
I can anticipate some questioning this design tactic. You can use a lessor subwoofer with a 250W plate amp and do the same design. Most of those lessor drivers cost pretty close to the same price as the Shiva-X. The Shiva-X will give close to, or more than the same output as those lessor drivers simply because it is MUCH more linear under the 30-35mm of stroke required at 250-300W of output. At that output level the BL curve of the Shiva-X is nice and flat, and the suspension design is not stressed. The cheaper drivers will be at their limits. Which would you rather have, a driver running WELL within its capability or a cheaper one running at its limits? Easy choice for me..
Estimated Cost:
Shiva-X: $165
Plate Amp: $100-$200
Port: $15
Stuffing: $10
MDF: $20
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Total: $310-$410
If you compare this to a commercial design you might want to look at the SVS PB12-NSD which is $599 internet direct. Your amplifier limited & port limited with this design so if you want more linear output, you need a bigger cabinet, and more power. That version will be next.
