Cubo 18:
Cubo 18 is a multi purpose, stand alone bass bin that, like Cubo 15, will equal or out run a single 18" BR*, of similar size, from ~ 40 Hz and up in terms of sensitivity. Cubo 18 works with a wide variety of 18” drivers. It has a cut list from just over a single 18 mm*** sheet (244 x 122 cm) / (8' x 4') with a single angled cut. Cubo 18" realizes a cost effective, small and light weight enclosure following the KISS-principle.
Development:
In 2007 the first prototype was build and tested. Cubo 18" is the 5th prototype in a line of hybrids aiming at the achievements as stated above.  Cubo 18 Standard and Cubo 18 Extended will both work with a wide variety of drivers, if uncertain which one will be most suited, build Cubo 18 Extended or mail me at This email address is being protected from spambots. You need JavaScript enabled to view it.
Size: 62x62x65cm (HxWxD)    
Frequency: From 40 Hz up to 110 Hz    
Enclosure Type: Hybrid

3D Model (by K-M-Sound-System):

Cubo 18 Rebated 6mm:

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Cubo 18 Extended Rebated 6mm:

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Footnotes: 18” drivers preferably with an EBP of 100 or higher; Fs (22-42 Hz), Qts (0.25 - 0.58), Vas (200 - 450 L) / (7.4 – 16.7 ft^3). Where EBP = Fs / Qts . Measurements will follow.
 
Cubo 18/15 (difference): Cubo 18 is 3 cm (/ 1 1/6th inch) deeper then Cubo 15. Due to phase similarities Cubo 18 and Cubo 15 can be  used together without noticeable issues. Cubo 18 has on average slightly more output for a given input in comparison with Cubo 15 (based upon electro-mechanical relatively similar drivers), especially between Fc high and Fc low,whilst Fc high and Fc low, remain similar (= cut-off frequency).
 
 
 
 Cubo 18: Front view
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Cubo 18: Side view without side panel
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Cubo 18: Driver for comparison
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Cubo 18: Detail magnet and bracing
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Cubo 18: Magnet facing out
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Cubo 18: Magnet in chamber
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Cubo15's Avatar
Cubo15 replied the topic: #24425 1 week 1 hour ago
Did you try the Fane with the magnet visible or magnet inside the chamber? That orientation has some influence on how deep the driver goes in Cubo 18 Extended, although most of it is due to Cubo 18 itself and not the driver. The RCF LFX451 is a good sub driver so it might change how deep it goes a bit but not by much. Because the RCF has good Xmax you can use o bit of EQ to get most out of
it but if you need much deeper bass Cubo Sub might be a better option for it.

I usually make a 18 - 30 millimeter ring on the baffle that has two sets of bolt patterns in it. It has 8 t-nuts for the new driver and spaced in the middle between those holes, 8 clean holes for the old driver. The ring is then mounted onto the baffle using hex bolt countersunk heads, so the ring surface is flush. The new driver can then be mounted with short bolts via the t-nuts. I like to countersink the t-nuts a bit, so that the entire bolt threat is used before exerting maximum (bolt clamp) force on the threat. The bolts are 17 - 29 mm plus whatever extra length is need for the driver, so they don't touch the baffle of the Cubo, this means they might need to be cut to length.

I've seen those clamps used before on heavy drivers, although I've never used them, they seem capable. So if implemented the right way that could be an relatively easy fix.

Best regards Cubo
sweetvibes-inc's Avatar
sweetvibes-inc replied the topic: #24419 1 week 6 days ago
Hi There Mr Cubo,

I am wondering if you can help with this problem.

I have four Cobo 18 extended that were loaded with FaneXB's 1000w 8ohm they were ok but the bass was not quite deep enough so,
I have now upgraded to RCF LFX451- 18" 1800w 8ohm. The problem is the bolt pattern and the cut out hole are very different therefore; I may have to use clamps instead of m6 bolts and T-Nuts not having enough space to get a router and a drill in the cab to work on the baffle. Can I place another baffle on top of the existing one and what difference will it make to the performance and sound quality.

Mounting information: RCF LFX451
Overall Diameter: 465 mm / 18.3 inch
Bolt Circle Diameter: 442-447 mm / 17.4-17.6 inch
Bolt Hole Diameter: 6.5 mm / 0.25 inch
Front Mount Baffle Cut-out: 424 mm / 16.7 inch
Rear Mount Baffle Cut-out: 424 mm / 16.7 inch
Depth: 194 mm / 7.63 inch

MOUNTING Fane XB
Overall Diameter 19.1" / 485 mm
Width Across Flats 18" / 457 mm
Flange Height 0.465" / 11.8 mm
Baffle Hole Diameter F/M 16.52" / 420 mm
Baffle Hole Diameter R/M 16.33" / 414 mm
Fixing Holes 8x 0.275" diam on 18.425" PCD
8x 0.275" diam on 17.25" PCD
8x 7 mm diam on 468 PCD
8x 7 diam on 438.15 PCD
Depth 8.07" / 205 mm

Thanks in advance and I look forward to hearing from you,

Sweetvibes-inc
sweetvibes-inc's Avatar
sweetvibes-inc replied the topic: #24418 1 week 6 days ago
Hi There Mr Cubo,

I am wondering if you can help with this problem.

I have four Cobo 18 extended that were loaded with FaneXB's 1000w 8ohm they were ok but the bass was not quite deep enough so,
I have now upgraded to RCF LFX451- 18" 1800w 8ohm. The problem is the bolt pattern and the cut out hole are very different therefore; I may have to use clamps instead of m6 bolts and T-Nuts not having enough space to get a router and a drill in the cab to work on the baffle. Can I place another baffle on top of the existing one and what difference will it make to the performance and sound quality.

Mounting information: RCF LFX451
Overall Diameter: 465 mm / 18.3 inch
Bolt Circle Diameter: 442-447 mm / 17.4-17.6 inch
Bolt Hole Diameter: 6.5 mm / 0.25 inch
Front Mount Baffle Cut-out: 424 mm / 16.7 inch
Rear Mount Baffle Cut-out: 424 mm / 16.7 inch
Depth: 194 mm / 7.63 inch

MOUNTING Fane XB
Overall Diameter 19.1" / 485 mm
Width Across Flats 18" / 457 mm
Flange Height 0.465" / 11.8 mm
Baffle Hole Diameter F/M 16.52" / 420 mm
Baffle Hole Diameter R/M 16.33" / 414 mm
Fixing Holes 8x 0.275" diam on 18.425" PCD
8x 0.275" diam on 17.25" PCD
8x 7 mm diam on 468 PCD
8x 7 diam on 438.15 PCD
Depth 8.07" / 205 mm

Thanks in advance and I look forward to hearing from you,

Sweetvibes-inc
Cubo15's Avatar
Cubo15 replied the topic: #24393 2 months 2 weeks ago
Those 3 are all in the same league (Cubo 18 Standard drivers) but I would start with the 3rd option

Best regards Cubo
disco's Avatar
disco replied the topic: #24392 2 months 3 weeks ago
hello) what will fit the best? there is 18" 1- fs32 re6,8 qms 12,2 qes0,35 qts 0,339 vas443l mms123g bl21,4 windight deptn 8mm coil 22mm cms0,27
2- fs 27hz qts0,25 qes 0,26 qms5,4 vas620 sd1288mm bl20,3 coil height20mm depth8mm
3- fs31 qts0,28 qes0,30 qms 7,1 vas430l sd1288 cms 0,16 coil20mm depth8mm bl23
Cubo15's Avatar
Cubo15 replied the topic: #24381 3 months 1 week ago
Hi,

Efficient speakers (like the 2241G) often excel in Cubo's, with a slight rising response, that will give them near the same output as (the same driver in) a double 18" reflex cabinet. Cubo's are strong at 50 - 80 Hz, which is were most energy in almost all music is, they do go lower though.

Best regards Cubo
puffah's Avatar
puffah replied the topic: #24378 3 months 2 weeks ago
  • Hi Hi ma
Hi my name is nathan. I have 8 of the old jbl sr single 18 subwoofer boxes. the jbl sr4718. They kind of are more of a midbass box then a sub. I wanted to pull the drivers and find a better box that might make them more boomy in the low end. I know its a good driver in a bad enclosure. Has anyone used the jbl 2241g subwoofer in these cubo 18 boxes. Any idea how they would sound or if its a good idea/match with this driver. Thanks nathan
Cubo15's Avatar
Cubo15 replied the topic: #24365 4 months 4 weeks ago
Yes,You might theoretically 1 or 2 Hz extension but practically this isn't ever reported as a problem.Best regards Cubo
t.geessounds's Avatar
t.geessounds replied the topic: #24364 5 months 17 minutes ago
www.parts-express.com/lavoce-san18402-18...oofer-8-ohm--293-729

also can i get away building the cubo 18 570mm wide? need them to fit in my car
Cubo15's Avatar
Cubo15 replied the topic: #24363 5 months 7 hours ago
Hi, is that a new brand?

The 184.03 should work well in Cubo 18 Extended and Cubo Sub.

Best regards Cubo
t.geessounds's Avatar
t.geessounds replied the topic: #24361 5 months 4 days ago
hn

can the LaVoce San 184.03 
18" neo work well in the cubo ex well?
thanks
Cubo15's Avatar
Cubo15 replied the topic: #24268 1 year 2 months ago
The box 18/500 is one of the best 18" budget drivers out there (for Europe), it even has some specs (like the 4" VC and the aluminium chassis) that are usually indicators that it isn't in fact a budget driver. Where it does go wrong (although for its selling price you can't blame them), the 18LW2400 goes right, putting itself in a class above the 18/500,

So 6 vs 8 each with their respected power handling sounds fair. For the 18/500 I would go for 500 - 700 W per driver, with the 18LW2400 I would look at 750 - 1250 W.

Best regards Cubo
Swanndog's Avatar
Swanndog replied the topic: #24265 1 year 2 months ago
Can you advise if the Thomman the box 18/500 speaker would be a good choice for a budget option for the cubo 18 extended ?
Details here images.thomann.de/pics/atg/atgdata/docum...85008a_uk_screen.pdf

I have previously used the 18 sound 18lw2400 and was super impressed with the results when using 6 in a mono stack. I now have 8 unloaded cabs but do not have the budget for 8x 18lw2400. Would you suggest having 8x the box 18/500 loaded cubo18 would be comparable to 6 x 18lw2400 ? Or would it be better to save a little more £ and go for 6x 18lw2400 that i have had before and i know works well ? More is not always better so im led to believe
Thanks in advance
Cubo15's Avatar
Cubo15 replied the topic: #24223 1 year 4 months ago
It is possible to add the Extended piece after building a Standard. It will be a bit of an operation though, so if you're happy with the sound as of now, I would think twice before fixing it. Remember that the Extended piece is an optimisation rather than a necessity, so EQ can be a viable alternative indeed.

If you have made no alterations to the large triangular bracing in any way, I would add the Extended panel in 2 parts/ pieces. One from the left wall to the bracing and one from the right wall to the bracing. I would dry-fit the pieces to make sure they're a snug fit and get all the dirt and dust from anything the glue will touch. Then using a 1-component, filling PU tix (like: www.bisonprof.nl/nl-nl/producten/715-hou.../product/312-pu-tix/ ) spread out on both the enclosure walls, as well as the pieces to be fitted. I would use something like a piece of wood (or a nail gun) to support it in it's place while drying.

Alternatively, you could take out a part of the bracing with a jigsaw, then place the Extended bit in one piece. If you add wooden corner blocks to the Extended panel, you can use short screws and glue to add it from the inside.

Best regards Cubo
IainB's Avatar
IainB replied the topic: #24221 1 year 4 months ago
Hi Mr Cubo,
Ive recently purchased a pair of Cubo 18s and have since found out that they are standard and not extended, Im intending to use a pair of Fane 18xb colossus drivers, which if I remember correctly you recommend the extended version.
Short of the long question... is it possible to add the extension after the box has been built (I know if wont be pretty) or shall I just keep it as standard and play around with the EQ.
Cubo15's Avatar
Cubo15 replied the topic: #24151 1 year 8 months ago
Hi,

You can use the BMS 18n862 in Cubo 18 Extended but the cut off will be closer to 35 - 40 Hz. For HT I would rather use Cubo Sub instead, which will also suite the 18n862.

However, to be honest my first choice would be a 200 litre internal reflex cabinet tuned to 20 - 25 Hz (per driver). Cubo Sub will be much louder as a reflex cabinet and will do 30 Hz but to get the full benefit of the large Xmax of the driver, you might want to tune lower.

Best regards Cubo
Popeye's Avatar
Popeye replied the topic: #24149 1 year 8 months ago
Hi Mr. Cubo; I have two BMS 18n862 in bass reflex enclosure. I want make two Cubo18 normal or extended for the home theater system (my target is 30Hz frequency cutoff). Can I use my BMS drivers? Thanks in advance, I'm sorry for my bad english.

www.bmsspeakers.com/index.php?id=18n862_thiele-small
Cubo15's Avatar
Cubo15 replied the topic: #24111 1 year 10 months ago
That will work, the added horn length in combination with the larger horn mouth will improve the output of the upper part of the frequency response. Say 65 Hz and up, which is right in the lane of what the 18W1300 is good at anyway..

Best regards Cubo
Maikolmks's Avatar
Maikolmks replied the topic: #24109 1 year 10 months ago
I quickly made a drawing to explain it better
Maikolmks's Avatar
Maikolmks replied the topic: #24105 1 year 10 months ago
Hi Mr. CUBO, recently you advised me the CUBO18 Extended for my 18W1300. I wanted to ask if you can increase the size of the cabin as shown in the picture.
This way I would have more space for the tops that will go over it.
c.stam5's Avatar
c.stam5 replied the topic: #24037 2 years 2 weeks ago
Hello mr. Cubo,

Thank you for your reply! I did not know that this forum was only English so that's why I don't reply you in dutch ;).
I will send you an email to ask you for some detailed information (maybe a technical drawing :)).

Thank you very much!
Cubo15's Avatar
Cubo15 replied the topic: #24028 2 years 2 weeks ago
Welkom met de eerste Nederlandstalige post op dit forum!

For that specific design you can best contact me (in het Nederlands) through e-mail, questionsaboutcubo at gmail dot com.

I can already tell you that the L18S800 is a nice woofer for Cubo 18 Extended and that loosing that extra cm is not a problem ;)

Best regards Cubo
c.stam5's Avatar
c.stam5 replied the topic: #24025 2 years 3 weeks ago
Beste meneer Cubo,

Ik ben nieuw op dit forum (dit is überhaupt het eerste forum waar ik iets post, maar ben een geoefend lezer zullen we maar zeggen ;-)) en heb met veel interesse het topic over de RCF L18P300 gevolgd waarvan 14 extended exemplaren zijn ontworpen/gemaakt. Nu is het zo dat ik enige tijd geleden 4 stuks RCF L18S800 woofers heb gekocht en wil graag hornloaded subwoofers maken als vervanging van mijn huidige basreflex kasten. De reden dat ik over wil stappen op hornloaded is dat ik zo af en toe m'n subs ook buiten wil gebruiken, en ik dit met m'n basreflexkasten niet red.

Mijn interesse gaat uit naar het speakerplan zoals gebruikt bij de L18P300 woofers omdat ik vermoed dat dit bij de L18S800 ook zal werken, alleen wil ik graag weten of het misschien mogelijk is om nóg een extra centimeter van breedte van de kast af te snoepen omdat ik dan 2 kasten naast elkaar in mijn aanhangwagen kan vervoeren.

Ik zou u dan ook willen vragen of u de instructies welke u destijds heeft gedeeld met de makers van de 14 L18P300 kasten ook met mij zou willen delen (indien dit met de L18S800 gaat werken). En misschien kunt u in het kort omschrijven hoe ik eventueel het beste die extra centimeter kwijt kan.

Alvast bedankt!

Met vriendelijke groet,

C. Stam.
Cubo15's Avatar
Cubo15 replied the topic: #23907 2 years 3 months ago
Thanks! World domination is now a matter of time ;)

Best regards Cubo
DJGARAM's Avatar
DJGARAM replied the topic: #23900 2 years 3 months ago
Mr Cubo.
I would like to congratulate you for your work.
And to say that the Brazilians are adhering to their brilliant work.
There are many T18 users around here.
Many are happy, in every sense, in up grade, for Cubo18.
Congratulations, and thank you for your help.