TH-18 Flat to 35hz! (Xoc1's design)

@PetroRobot

I can't quote you for some reason

Yes, Cubo kick 15 is wider than TH18 in the original plans.

Look for posts by user 'jo bg' in this thread and on Speaker Plans forum.

Jo bg contacted Cubo to ask if the Cubo kick could be reduced in width to match the TH18. Then they can be stacked neatly like this. Cubo said yes, but the crossover frequency should be raised a little bit.

Jo BG posted that they are extremely happy with the results, so basically I copied their idea


There's a post somewhere where jo bg provides the frequency they use to cross the sub and the kick. It's saved on my laptop but at the moment I'm on my phone. I can look later, but all the information is on here or speaker plans forum

Good luck 👍
 
thanks! found something on freespeakerplans about that
Soundsystem of Jo BG is Bassi Gradassi (i think you can found some old photos in this thread). Heard it this summer and was magical. Clarity and power at the same time without the slowness of the typical dub system.
First time didnt use earplugs at a party.
 
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One of our crew @FinBot built a pair of mk1's many years ago, along with some of Art's SyntripP. The TH-18 boxers are pretty battered and have a few leaks and we were thinking about rebuilding them (along with another 4). I have read through a lot of this thread and debating whether to rebuild the mk1's or try the elusive mk2's.

Most of the 'bread crumbs' on the mk2's I can find show:
-the corner bracing removed (except for the one sealing the handles) for more volume
-Cone correction (eg post 2,963 for 18SW115s and some earlier posts). There's examples of builds with bracing in the stub and some without.
-Longer horn path linked to implementing cone correction.

Did i miss much else?

I know Art and a few others have dropped some hints on how DSL implemented the cone correction, but I'd rather stick to what the community has developed.

I plan to do the cad work in Fusion 360 and can share the 3d model and cut sheets if people want. Will also aim to add in skids to help them stack, pole sockets and bracing around the mouth to attach grills.


TH 18 MOD.jpg TH18MK1_2Prelim.jpg Revised cone correction layout3A.jpg 1660165080110.png
 
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Deman,

The "3A" revision is OK, provided you eliminate the small "Y" brace in the "stub".
Throat Stub.png

As Tom Danley has explained, (akin to radio-frequency engineering) "stub" or resonant stub is a length of transmission line or waveguide that is connected at one end only.

He's used them in several of his TH designs.

Art
 
Hey guys, I built 4 TH18 with 18tbx100 and they sound great! Would upgrading to the 18sw115 be worth the money for the increase in max spl and power handling? The weight savings doesn’t make a huge difference to me, but more spl and headroom is the goal. Thanks
-Ben
 
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Ben,

Depends on your definition of "worth it", and "better", how much amplifier power/voltage you have available, as well as the ac power available.

The 18sw115 should provide ~4 dB more output than the 18tbx100 , but will require >~5dB more power to do it.
Best to check the Hornresp sims for both drivers and specifications of your amps to verify.

Art
 
For 3dB more you need double your power for that driver , for another 3dB more is another double , so if you have a 1.5kw per channel amp at 8ohms you will need , 1.5x2x2... 6Kw to feed that driver in order to get 5-6db more...
As you have 4 cabinets , you can use 4 inuke 6000 unless you have bigger amps like the china clones (CVR, Sanway, Admark)
And you need to get the 4 ohm drivers to get the max out of a given amp channel
 
Thanks for the help gents, I’m running a sanway D20KQ which is 4000x4 @ 4 ohms. It measured 124v before clip. Provided the venue has adequate power available to run it wide open ha. That sounds like a decent option for more output without having to get a bigger trailer for more boxes. Cheers!
-Ben

 
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hello friends, it is an honor for me to read our passion here with good and bad opinions all threads. Well, what happened to someone here with a driver in the simple xoc version because the pressure is decreasing and correcting the cone to be flat helps a lot perhaps and i will do this type. I have 4 buckets BWP18/4 5" cone, what size should I make for this piece? I saw in the drawing 100mm, that is 50/50 middle. What should I do? how counting..

Pushed 2x PSSO HP-3200 2x800rms 4ohm
IMG_20240219_061244.jpg
 

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So 4db more per driver times 4 is 16db better than the current 18tbx100's?
So 2 nukes 6000 with 4 ohms sw115's will get 16dbs. More than what he have?
Four cabinets equally powered and mutually coupled increase +12dB over one cabinet.

Four dB per cabinet is four dB more total, using the same amount of cabinets, swapping cones.

4000 watts should be OK for the BC 18SW115 if the four ohm version (BC 18SW115-4) is used.
124v is ~3800 at 4 ohms, or 1900 at eight, enough power to cook the 8 ohm B&C 18TBX100.