Free Speaker Plans

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:

 

Cubo 18 Extended Rebated 6mm:

 
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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Posted: 6 days 3 hours ago by easy my youth #22062
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Thanxx for the help cubo - not to mention a quick response ! 30 metres throw is not bad at all, I was expecting less. Cubo sub is what I plan to build. Yes, I would more than welcome cubo 15 kick plans, a couple of questions : how high can it play, what 15s do you suggest . Have access to RCF, B&C, Emi, 18 Sound. PD, Void, Fane are super expensive here. Ferrite magnet is OK with me. So I would like to give it a try. Any phase or comb filtering issues when crossed to horn or reflex midtop. Thanxx again, easy my youth
Posted: 1 week 45 minutes ago by Cubo15 #22057
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The consensus is that Cubo's have the same "throw" as a reflex cabinet but louder, as you have used 18" reflex before I guess you know what to expect when used outside.
I've noticed that Cubo Sub throws a bit further. If one would say a Cubo 15 throw's up to 20 meter, than a Cubo Sub would throw up to 30 meters, whereas a scoop will throw 40 - 50 meter.

If cabinet size/portabilty isn't an issue, you could try Cubo Sub instead, that would also make sure you aren't missing any lower notes. The L18X451 is a great driver for sub duty and will work in Cubo 18 Extended and Cubo Sub equally well.

Do yo need plans for 15" kicks as well? I've been working on Cubo Kicks for quite some time now and I basically just need a few people tell me how great it is before I dare launching the plans officially. The benefit is that it's for 15" drivers, stacks and looks nicely with other Cubo's and is easy to build as well.

Best regards

Cubo
Posted: 1 week 1 day ago by easy my youth #22053
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Greetings from Jamaica. I am rebuilding my sound and considering cubo 18 extended. I play roots reggae, cd and vinyl, strictly outdoor venues, 300-500 persons. Box portability and weight are not issues because I have storage, transport, and many helping hands. Ease of construction is important, no access to CNC, etc. I have used 18 scoops in the past but this time around will be mixing live music from time to time, so I am thinking cubo 18 extended using rcf lf18x451 driver. Comments suggest cubo 18 is indoor venue only. System is 18 sub to 15 kick , 12 mid, 1.5 compression driver. Any comments, questions, or suggestions welcomed. Give Thanxx, easy my youth
Posted: 1 month 1 day ago by Cubo15 #21976
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For the Lomax you can use a high pass at 35 Hz or higher. I suspect it to work best up to 100 Hz.

Best regards

Cubo
Posted: 1 month 1 day ago by haze #21974
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Thank you very much for availability
probably I'm going to cubo extended because of the size
which hpf is recommended for this woofer? Keep 40hz or I can go a little low
Posted: 1 month 1 day ago by Cubo15 #21973
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The Peavey Lomax 18 will work best in Cubo 18 Extended, with the magnet in the horn (visible). The Lomax 18 will also work in Cubo Sub.

Best regards

Cubo
Posted: 1 month 1 week ago by haze #21952
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i have some peavey lomax18 can they work?
fs 31,5
re 5,4
sd 0,118
bl 23,4
vas 294
mms 194
qms 11,15
qes 0,33
qts 0,386
xmax 10,2
1200 w cont.
Posted: 2 months 7 hours ago by wahyudi #21901
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thanks, i like it.
Posted: 2 months 1 week ago by Koji Ohno #21863
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my lovely 4 cubo 18.. :side:
Posted: 2 months 2 weeks ago by Cubo15 #21839
Posted: 2 months 2 weeks ago by Vaibhavdj141996 #21838
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what is the difference in Magnet facing out and in magnet in chamber of cubo 18? what is the advantage of magnet in chamber?
Posted: 2 months 3 weeks ago by Cubo15 #21822
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Cool, feedback is always welcome, as are pictures!

Best regards

Cubo
Posted: 2 months 4 weeks ago by don_caniball #21818
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thanks a lot , i´ll start with 4 pcs in next month i hope ! :) and when they´ll be completed and tested , i´ll give some feedback ! good luck :) and i am sorry for bad english i am from slovakia as i said before .
Posted: 2 months 4 weeks ago by Cubo15 #21817
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Hi,

I would start with Cubo 18 Extended, with the magnet outside. I like the LF18G401 as it's pretty efficient (3% +). If you want to maximise on efficiency you can put it with the magnet inside the chamber but with the magnet outside would be my initial bet.

Best regards

Cubo
Posted: 3 months 10 hours ago by don_caniball #21810
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hello , which type (extended or classic) is better for RCF LF18G401 and with magnet inside or outside :) thanks a lot ! greetings from slovakia ! :)
Posted: 3 months 3 days ago by Cubo15 #21797
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@Tweeter_Box: With the magnet inside the chamber I would say 35 - 40 Hz, 12 - 24 dB/ octave. What sounds best, is best untill proven otherwise. To your previous 2 questions I believe the answer were yes and yes, can't remember exactly what questions they are tho.

@Crossed: that's good news, you might be able to use 6 Cubo's for two 2 x 12" tops (/ 1.5") if it's bass-heavy music. The again, if I had your current setup I wouldn't need my system to grow ;)

@PrettyHard: It would work but I don't think it would give the deepest bass possible and need a bit of power to get going Xmax-wise everything is very OK. Someone from the Philipines has build two and since he responded quite happy I asume it went well.

Best regards

Cubo
Posted: 3 months 4 days ago by Tweeter_Box #21794
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hi, whats the recomeneded HPF & slope for cubo extended pd1850 loaded with magnet inside the chamber? does the polarity need to be reversed? i find it plays better with polarity as normal
Posted: 3 months 1 week ago by Tweeter_Box #21761
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...
Posted: 3 months 3 weeks ago by crossed #21743
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And two more Cubos enter the world.

This will bring me up to four total and should give me a nice system for medium size parties. I built the dual 12 + 1.5 last month and two Cubos were not nearly enough to keep up.

Posted: 3 months 3 weeks ago by PrettyHard #21741
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Hi Cubo

i want to ask if the P Audio c18 650el can work well on cubo 18 cab?

www.paudiothailand.com/pdf/products/C18-650EL3.pdf

Thanks in advance
Posted: 4 months 1 week ago by Cubo15 #21687
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To celebrate the 40 year anniversary of the Rubics Cube:



@Kiz77: That's an easy one, the LF18G401 wins by 3 dB (that's an insiders joke about n0).

Best regards

Cubo
Posted: 4 months 1 week ago by kiz77 #21682
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Hello @Cubo, I am going to making a pair of these very soon for a nice low end, i have two drivers in mind, the P-Audio E-18ELF Or The RCF LF18G401, Which would you recommend?
Posted: 5 months 3 days ago by Cubo15 #21658
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I like to base whether the driver faces in or out based on the specific driver parameters. As a rule of thumb with the magnet in the chamber gives slighty lower tuning, while the driver facing out gives most output.

Best regards

Cubo
Posted: 5 months 1 week ago by Knobs100 #21615
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Do you prefer speakers facing out or in. i cannot hear a difference with the naked ear
Posted: 5 months 1 week ago by Cubo15 #21612
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I built 5 cubo 15 a couple of years ago and put eminence cappa pros and they sound pretty good especially inside. I can get 4 JBL 18" neo speakers that came out of vertec boxes for $100 each. I was thinking of building 4 cubo 18 to go along with the 15. I can run them on different Crown XTi amps and cross them a little different if I need to. My question is will 4 of the 18 give me the thump I am looking for live music outside or do I need to look at a horn loaded W cab
Afaik there are different 18" models in different Vertec-subs. Since most of them seem to be high powered drivers, as opposed to the Kappa Pro's, I expect them to have lower power compression and higher power handling, so two reasons to expect them to go quite a bit louder than the Kappa's.

Only you can decide if they will thump enough, as I have no reference to what you consider to thumb enough. But if you want them to thumb beyond 20 - 30 meters, the W-bin's are a better choice, tho you might find there are better designs out there as the W-bin's aren't exactly going low.
Finnaly i made a few cubo18s ex, with a strange STX driver stx.pl/sw-stx-18-4-1300-8-f-s-mc.html.
Im quite happy because performance is very good, and value ratio is excelent (driver for 100E). Now I have ask. If I play magnet inside horn and positive wireing how much i need delayed BR to make a phase correct. And if I play in the same way but in negative wire I need delay?
Personally I don't correlate negative or positve wiring to different amounts of delay. Positve or negative wiring can end up, better in phase with your tops (and that is dependant on your tops, not your bass cabinets).

Delay in general anywhere between 1 - 5 msec, tho most Cubo-teers don't use delay, whether they have the option or not ;)

Best regards

Cubo