Size: 62x62x62cm

Frequency: From 40 Hz up to 110 Hz

Enclosure Type: Hybrid

Recommended DriverKappalite-3015lfKappapro-15lf-2kappa-15lf or  drivers with EBP of 100 or higher; Fs (27-50 Hz), Qts (0.21 - 0.41), Vas (150 - 300 L) / (7.4 - 11.1 ft^3). Where EBP = Fs / Qts (strictly speaking it's Fs / Qes)


Cubo 15: Cubo is a multi purpose, stand alone bass bin that will equal or out run a single 18" BR*, of similar size, from ~ 40 Hz and up in terms of sensitivity. Utilising a non-expensive driver such as the Eminence 3015LF, Kappa 15LF and Kappa 15LF Pro** and a cut list from a single 18 mm*** sheet (244 x 122 cm) / (8' x 4') with a single angled cut, Cubo 15" realizes a cost effective, small and light weight enclosure following the KISS-principle.

Development: In 2007 the first prototype was build and tested. Cubo 15" is the 4th prototype in a line of hybrids aiming at the achievements as stated above.  The measurement below shows the gain over the stated bass reflex (see * for details). Cubo 15 plans are also available in an Imperial version, plan available on request.

Versions: As a rule of thumb:

Qts x Vas > 120, Cubo Standard
Qts x Vas = 100 - 120, Cubo Extended or Standard
Qts x Vas < 100, Cubo Extended
Qts x Vas < 50; Cubo 15 Extra Extended

Magnet orientation:

The driver mounted with the magnet visible (the magnet in the horn) typicall gives the lowest bass response and slightly better cooling of the voice coil. Mount the driver with the magnet inside the chamber for most output around 60 - 80 Hz or the highest possible crossover frequency.

Footnotes:* 18Sound 18LW1400 in a 175 liter bass reflex tuned to 37 Hz. (6,6 ft^3) vs. Cubo 15 ; Eminence Kappa 15LF.          ** Apart from these drivers Cubo will work with a wide variëty of 15" drivers preferably with an EBP of 100 or higher; Fs (27-50 Hz), Qts (0.21 - 0.41), Vas (150 - 300 L) / (5.5 - 11.1 ft^3). Where EBP = Fs / Qts.  If you're uncertain if a driver is suited, PM or mail me at This email address is being protected from spambots. You need JavaScript enabled to view it.         *** If you want to use 15 mm material use 11-ply Baltic birch, nothing less. Plans available on request.

Designer: Cubo15 [view profile]alt

 

Cubo 15 Standard Plan:

Cutsheet (clearly visible after download):

Cubo 15 Extended Plan:

Cubo 15 Extra Extended Plan:

Only the 2 inner horn panels are different from Cubo 15 Extended, all else equal.

 

 



dajnaton's Avatar
dajnaton replied the topic: #24815 4 weeks 23 hours ago
Hello Cubo15, greetings from Venezuela. I would like to know where to download the plans for the 15 cube version using 15mm wood sheets.

Would you recommend MDF?

I have been using Mini Scoop 18 for years and would like to change them for greater portability.

Excuse my english, use google translator.
This email address is being protected from spambots. You need JavaScript enabled to view it.
nemsik's Avatar
nemsik replied the topic: #24793 2 months 8 hours ago
Thank you for the explanation :)
Cubo is a great project, thanks for sharing it on the Internet!
Cubo15's Avatar
Cubo15 replied the topic: #24788 2 months 9 hours ago
@nemsik:

Should I remake my cubo to an Extended version?

Nahh, I wouldn't do that. I've tried a similar driver in Cubo 15 Standard and it measured pretty well. Flat frequency response is imho a bit overrated, dips and peaks due to indoor room-nodes will be much larger and processing or placement should fix that.

@MarioJ77:You can calculate which Cubo version you need, using the Qts x Vas rule posted on the plans page: Cubo 15 Plans

A Cubo 15 is a safe bet, another cabinet might be better depending on your specific needs, which I would need to know before I'm able to answer.
MarioJ77's Avatar
MarioJ77 replied the topic: #24784 2 months 2 days ago
I plan to build a Cubo 15 speaker box The Box 15LB075-UW4 with the following features: Fs 40Hz, Re 3.6 Ohm
Qms 8.48, Qts 0.4, Qes 0.38, Vas 158.91L, Mms 0.12kg, Cms 0.14mm / N, BL 16.7 Tesla m, Sd 0.09mm2, Xmax + -4mm.
I'm wondering which Cubo 15 plan I need or to do some other box construction for this speaker.
Thanks in advance for replying and donating the plan for the suggested box.
nemsik's Avatar
nemsik replied the topic: #24783 2 months 4 days ago
Thank you for your answer!
We are talking about Vas = 247L and Qts = 0.24, so I made mistake because Qts x Vas = ~59.3 but still I should use extended version, right?

"So the overall tuning doesn't really change, what changes is the flatness of the frequency response and driver-to-Cubo matching based on the Vas and Qts"
I was afraid that I changed tuning dramatically...
Should I remake my cubo to Extended version? What do you think about it? Of course, I can little flatness the frequency response by the sound processor.
Maybe do you need additional driver parameters?
Cubo15's Avatar
Cubo15 replied the topic: #24782 2 months 4 days ago
Cubo Standard has the largest rear chamber with the shortest horn path length, aiming at drivers with a medium to high Vas and Qts. Cubo Extended trades some of that rear chamber volume for extra horn length, the extra horn length tunes the Cubo lower but then again the loss of rear chamber volume increases that tuning. So the overall tuning doesn't really change, what changes is the flatness of the frequency response and driver-to-Cubo matching based on the Vas and Qts. Same applies to Extra Extended, naturally for lower Vas and medium to low Qts drivers.

If you cannot interpret Vas and Qts separately, use the product rule. So what Vas and Qts are we talking about?
nemsik's Avatar
nemsik replied the topic: #24781 2 months 6 days ago
A few years ago I build Cubo 15 STANDARD, and I used a driver where Qts x Vas = 50.3
So I should make a Cubo Extended or Extra Extended.
Anybody tell me a general difference between the Standard and Extended version when I use a driver that has Qts x Vas = 50.3 ?
I guess that this affects the frequency response, but how?
What else?

Thank you! :)
A King's Avatar
A King replied the topic: #24779 2 months 3 weeks ago
Thank you for sharing
Cubo15's Avatar
Cubo15 replied the topic: #24610 10 months 2 weeks ago
Well, let's slim you choice down immediately to the Kappa 15Lfa or the Kappa 15a, both drivers will work in Cubo Kick 15 and Cubo 15 (Extended for both). If you're ever going to use this for PA, I would slightly favor the 15lf for Cubo 15 but not necessarily for Cubo Kick. As you're going to use this at home you can get 2 of the same drivers and put one in each.

Best regards Cubo
Tommyj1989's Avatar
Tommyj1989 replied the topic: #24602 10 months 2 weeks ago
I’m building a cubo 15 sub and a cubo 15 kick please can you tell me the best driver to put in each 

Delta  15Lfc
Delta 15a
Kappa 15Lfa
Kappa 15a

It’s only going to be for home use really but some advice would be great. Thanks 
heathkit's Avatar
heathkit replied the topic: #24598 10 months 3 weeks ago
Thank you for your quick reply and great advice. I will likely do a 75 - 100 liter ported cabinet with the Faital woofer.

Kind regards,
Richard
Cubo15's Avatar
Cubo15 replied the topic: #24597 10 months 3 weeks ago
Cubo 15 is not a mid bass cabinet in anyway, it's purely meant as a bass cabinet up to about 100 - 120 Hz. (driver dependent). For home hifi, any of the mentioned 15" drivers in a closed or ported cabinet will work (around 75 - 100 liter tuned to 60 - 70 Hz). This will give you the highest crossover that's unlimited by band pass effects of various other PA oriented designs and around 96 dB/ W/ m.

The only Cubo design that will get close to a 350 Hz crossover is Cubo Kick 12, you would have to close one or several of it's ports to tune it to 60 - 70 Hz though. Sensitivity is typically over 100 dB/ W/m, so if you only have 1 - 10 W available this might make a sensible choice. If power isn't the limiting factor I would look at one of those 15" PA drivers in a closed or ported cabinet though.

Best regards Cubo
heathkit's Avatar
heathkit replied the topic: #24595 10 months 3 weeks ago
This CUBO 15 design looks good, but doesn't quite cover the range I need to go with my synergy horns. I need to cover from about 60 or 70 up to about 350 where the synergy takes over. Want good dynamics and pretty good efficiency, about 95 or so. This is only for home hifi, not pro sound reinforcement. Would like to use a 15", maybe a FaitalPro 15PR400, Eminence KAPPA LITE 3015LF, or B&C 15PS76. 

Danley Sound Labs makes a similar size synergy horn that is 3 way with 2-10" or 2-12" woofers that port into the horn. I'm not sure I want to try that, not sure the bass quality would be good enough. Thanks in advance for any suggestions.
IDonCarlo's Avatar
IDonCarlo replied the topic: #24591 11 months 6 hours ago
Where do I download?
Cubo15's Avatar
Cubo15 replied the topic: #24536 1 year 1 month ago
In this case I would advise Cubo 15 Extended for the 15NW100, although Extra Extended will also work.
mrdiego's Avatar
mrdiego replied the topic: #24532 1 year 1 month ago
so, if I use the B&C 15NW100, would you advise me to build a Cubo 15 Extended anyway?
Cubo15's Avatar
Cubo15 replied the topic: #24514 1 year 1 month ago
That depends, Pine is 500 - 650 kg/m3 also depending on shipment, manufacturer specifics and humidity. So for roughly an entire sheet of 18 mm ply --> 0.018 x 1.22 x 2.44 x density = 26 - 35 kg. As a reference Baltic is 650 - 750 kg/m3. If available I would also consider Meranti ply.

Cubo 15 Extra Extended is a safe bet as per rule of thumb, it will also work in Cubo 15 Extended though. If you're going for a high power driver like the 15NW100 and will sooner or later upgrade to a heavier amplifier I would consider using 15 mm Baltic birch (quality B/BB). Better safe then sorry.

Best regards Cubo
mrdiego's Avatar
mrdiego replied the topic: #24512 1 year 1 month ago
using 18mm wood, for example pine, how much could it weigh?

If I use B&C woofers, do I have to mount them in an extra extended cubo15? For example, the B&C 15NW100 has:
qts = 0.22
vas = 139dm3 (l)
So Qts x Vas = 30.58
Thank you
Cubo15's Avatar
Cubo15 replied the topic: #24510 1 year 1 month ago
There are plans available for Cubo 15 from 15 mm ply but in that case 11-ply Baltic birch becomes the only sensible choice. Alternatively you can use an 18 mm ply that has a lower density as Baltic birch (spruce, pine, poplar, etc.), these will be lower toughness as Baltic but will be as light as a Cubo made from 15 mm Baltic birch. Send me an e-mail at questionsaboutcubo at gmail dot com for the plans.

As for suitable drivers:

- B&C 15NW100 and 15TBX100
- RCF L15P400 and LF15G401
- 18Sound 15LW1400
- Faital Pro 15HP1020
- Celestion FTR15-4080 (there's like four different versions that are all suitable)

The B&C and 18Sound drivers are a t the upper end of your budget but really worth it if you're going to upgrade your amplifier in the future. The RCF drivers are older models but look like great value for money within you budget.

Best regards Cubo
mrdiego's Avatar
mrdiego replied the topic: #24509 1 year 2 months ago
eminence, , Eighteensound, rcf, celestion, maybe Beyma, B&C Are the brands that i can find in Italy. I would like to spend around € 200-250. Even something more powerful might be fine. In the future I could change amps. Also, would it be possible to build a 15 cube with 15mm wood? so it would be lighter, but I don't know how it might sound. Thank you Cubo15
Cubo15's Avatar
Cubo15 replied the topic: #24505 1 year 2 months ago
The KAPPA PRO-15LFC is a good choice for Cubo 15 Extended with about 600 W of amplifier power, if you use a 40 Hz high pass filter. To recommend any other driver I need to know your approximate budget and what brands are available to you/ your location.

Best regards Cubo
mrdiego's Avatar
mrdiego replied the topic: #24504 1 year 2 months ago
I want to build a cube15. I would like to use a 4ohm woofer and about 600w, as I already own the amplifier. which one could I use? with which cube 15? would the KAPPA PRO-15LFC go well with an extended cube? can you recommend anything else?
biggins's Avatar
biggins replied the topic: #24467 1 year 5 months ago
Hi Cubo, 

I have a quick question. Is it OK to mix the extended versions of the Cubo 15 with the original, non-extended version. 

My assumption is that it is not OK to mix designs as the extra horn length will cause issues with the phase alignment but just wanted to check.

Ps: thank you for your kick and sub designs. We have been using them South Australia and they have been sounding great  <3  For a picture of your designs in-situ, check the banner on my stalkbook page.

https://www.facebook.com/2ndClassSleeper/
Cubo15's Avatar
Cubo15 replied the topic: #24466 1 year 5 months ago
Well, you can always build Cubo 15 Extra Extended if you feel like it ;)
yanng22's Avatar
yanng22 replied the topic: #24465 1 year 5 months ago
Hi Cubo
My Kappa is an old version , the Qts x Vas =52.6 , ( the LF2 as 59.6).
That's why I hesitate , 52.6 is near the limit between the extra extended and extended plan.

Best regards