A new Cab design; Part II!!!

Russell Dawkins · « **Reply #80 on:** 16 Jul 2017, 09:43 pm »

I like the curved top, and it probably sounds better, being stiffer, The bottom of the cabinet is horizontal, right?

This is a good looking cabinet and the combination of the curve and the angle will certainly stop anyone from putting a flower pot on top and spoiling the sound!

One thing to watch out for: make sure the arc of the top does not have the same center point as the HF driver, i.e., that there is still a varying distance from the HF driver's center to the top edge, to distribute the frequencies affected by the edge diffraction.

EdRo · « **Reply #81 on:** 16 Jul 2017, 10:47 pm »

If I've done my calculations right, the wave guide is around 8.18" across. The baffle is 12" wide, and the top of the guide is 1.25" from the top of the baffle. Hopefully that'll be enough differentiation. We shall see. The proof's in the pudding, right? That's what prototypes are all about. Thanks for checking it out!

EdRo · « **Reply #82 on:** 16 Jul 2017, 10:51 pm »

My wife thinks the new top looks like Queen Nefertari's crown. I don't know if that's good or bad, but putting that curve in the top makes that panel automatically stiffer and less likely to have dips and surface deviation for finishing. I'm trying to think of form following function. Oh, and the bottom and the baffle are the only "flat spots" on this cab design. Nothing new, I'm sure, but it's new for me!

EdRo · « **Reply #83 on:** 16 Jul 2017, 11:02 pm »

EdRo · « **Reply #84 on:** 20 Jul 2017, 02:11 am »

Progress!!!

EdRo · « **Reply #85 on:** 20 Jul 2017, 02:53 am »

So...let me explain. This set of cabs will have an "inner" and "outer" set of baffles. The inner corian baffle is what you see here. It still needs the stainless threaded inserts and the woofer and port thru holes cut. The thru-hole near the top is for the Transducer Labs magnesium oxide dome tweeter. I put that curve in the top today, and I have to say that I think I'm starting to like this builds shape!
Back to the explaining. The outer baffle will bolt down on the inner baffle. The woof will have a heavy gasket material around it and will be squeezed between the inner and outer baffles to try to reduce vibration transmission to the cab. There will be a special material that sits on the back top edge of the port shelf that will go up to just above the woofer, to clean up some low/mids that might try to escape out that bottom port. I think that this could be the quietest set of cabs that I've ever built!

Pete Schumacher · « **Reply #86 on:** 23 Jul 2017, 06:53 am »

Quote from: Russell Dawkins on 16 Jul 2017, 09:43 pm

One thing to watch out for: make sure the arc of the top does not have the same center point as the HF driver, i.e., that there is still a varying distance from the HF driver's center to the top edge, to distribute the frequencies affected by the edge diffraction.

In this case, because the tweeter will be sitting 1.5" down inside an 8" diameter waveguide with a smooth circular arc profile from throat to mouth, edge diffraction is not a concern. The tweeter is effectively on a baffle with 4" diameter roundovers. Diffraction is well controlled and allows it to match the woofer directivity in the crossover range. That guide not only controls diffraction, it uses the diffraction shaping of the tweeter response to greatly reduce tweeter stress levels in the 1KHz region. The electrical transfer function will be at least 12dB down at 1KHz relative to the top of the tweeter band, allowing strain free crossover to the woofer anywhere between 800Hz and 1200Hz.

EdRo · « **Reply #87 on:** 17 Sep 2017, 05:11 pm »

Here are a few pics of my prototype nearing the home stretch.

LesterSleepsIn · « **Reply #88 on:** 17 Sep 2017, 06:18 pm »

Looks great Ed! I thought from the earlier photos that not only were the cabs peaked to the rear but the tops seemed to slant to one side. Perhaps an optical illusion?

Cheers,
Lester

EdRo · « **Reply #89 on:** 17 Sep 2017, 06:27 pm »

There isn't a slant to one side or the other(at least not intentionally

) I'm really excited about how these are starting to look. These might not be as curvy as my Aurora or Nimbus designs, but they have some pretty dramatic lines of their own!

otto802 · « **Reply #90 on:** 18 Sep 2017, 09:38 pm »

Quote from: LesterSleepsIn on 17 Sep 2017, 06:18 pm

Looks great Ed! I thought from the earlier photos that not only were the cabs peaked to the rear but the tops seemed to slant to one side. Perhaps an optical illusion?

Cheers,
Lester

The top is convex, so it could appear to slant depending on the angle of the photo.

EdRo · « **Reply #91 on:** 6 Oct 2017, 12:49 am »

Just an update on these; I weighed a cab with baffle in place, and it tipped the scales at 115.8lbs! Without drivers.

EdRo · « **Reply #92 on:** 6 Oct 2017, 01:12 am »

A woof and dome Tweet are 11.4lbs additional.

EdRo · « **Reply #93 on:** 11 Oct 2017, 07:11 pm »

Baffles are fitted. Ready to start driver sims for x-o design!

EdRo · « **Reply #94 on:** 11 Oct 2017, 11:21 pm »

Drivers help finalize the look.

EdRo · « **Reply #95 on:** 13 Oct 2017, 02:08 am »

These corian baffles buff up pretty well. It's amazing that those two baffles are the same material! I don't think that these should be painted at all!

bajaed · « **Reply #96 on:** 13 Oct 2017, 02:22 am »

Amazing work Ed! You're right about the baffles, no paint needed.

otto802 · « **Reply #97 on:** 29 Oct 2017, 06:35 pm »

The hard decision now is what color to paint the cabs? The black baffles are so shiny and sweet!

I'd love to see some examples and ideas of great color combos to go with the black baffles on these!

EdRo · « **Reply #98 on:** 30 Oct 2017, 04:51 pm »

Ready for paint finally. Now the question is, to work out the x-o before paint or after?

bajaed · « **Reply #99 on:** 30 Oct 2017, 10:29 pm »

I think a dark bronze/Brown flake would look great on those.