Cubo 15

Size: 62x62x62cm

Frequency: From 40 Hz up to 110 Hz

Enclosure Type: Hybrid

Recommended Driver: Kappalite-3015lf, Kappapro-15lf-2, kappa-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 4^th 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]

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.

Posts in discussion: Cubo 15

Cubo15 replied the topic:

#25055

1 year 3 months ago

It's not going to do great, do to its very low Vas (even compared to other 12" drivers). Its Vas is low, especially for use in a 15" enclosure, causing a large dip between 60 - 100 Hz. The PS100 will not have that problem (as its Vas is 3.5 times greater).

Tacatomon replied the topic:

#25054

1 year 3 months ago

Yes, I'm curious about the performance of the 12" in the Cubo 15 Extra Extended because it has a lot more excursion. Also, I have a 15PS100-8 to test out the box.
With a removable circular baffle for the 12" to fit the and seal the 15" box opening.

Cubo15 replied the topic:

#25053

1 year 3 months ago

Do you want to use a 12" driver in Cubo 15, or do you mean the 15HP1030 instead?

Tacatomon replied the topic:

#25052

1 year 3 months ago

How would the FaitalPro 12HP1030 perform in the Cube 15 Extra Extended?

www.loudspeakerdatabase.com/Faital/12HP1030#4%CE%A9

Cubo15 replied the topic:

#25036

1 year 9 months ago

That depends on the clearance in front of the drivers and the excursion they make. To make sure that the accordion surrounds of the two drivers can not touch each other you might want to use a spacer ring between the drivers. I.e. an 18 mm MDF ring between the drivers doesn't hurt the outcome but might not be needed.

Buje replied the topic:

#25033

1 year 9 months ago

Thank you, I have 4 Ev 15 dl 400, to test, the location, front to front, do you need any modification for this?

Cubo15 replied the topic:

#25030

1 year 9 months ago

It is, however a single driver with double the power handling will work just as well.

Buje replied the topic:

#25029

1 year 9 months ago

Cubo 15 isobaric is posible? thanks

Cubo15 replied the topic:

#25008

2 years 4 months ago

The high pass is good, I know that some Cuboteers cross Cubo 15 at 120 Hz or higher but I prefer 80 - 100 Hz myself, so I can't personally recommend it. The Turbosound tcx115b looks like a good choice, it won't be as loud as a Cubo 15 but it works better with the amplifier/ processing that you've got. So unless you're able to use additional EQ on the Cubo 15 (to suppress 100 - 150 Hz), I think the Turbosound tcx115 is a good choice. Best regards Cubo

savior replied the topic:

#25007

2 years 4 months ago

thanks cube, my problem is that I would use his original amplifier which has the cuts already set and not settable!
you say they won't do?
the amp delivers 550watt, the cut is from 38hz to 120hz.
however in the diagram I may see that the cut is at 40hz 12db.
I'm ignorant of technical data! i have manufacturing experience with cnc machines, but i have always built cabinets and heads for guitar amps designed by others.
do you think maybe a bandpass like the turbosound tcx115b would be better, which as a frequency range is very similar to my sw540 sub?

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Cubo15 replied the topic:

#25006

2 years 4 months ago

Those are actually pretty good drivers, I would use them in Cubo 15 Extended or Extra Extended up to about 80 - 100 Hz. The only thing lacking is the Xmax, I would use a high pass at 40 Hz and use about 500 W of amplifier power per driver.

Cubo

savior replied the topic:

#25005

2 years 4 months ago

hi cube, i'm savior from italy. i have a problem with 2 sub montarbo sw540. in practice they have the plastic cabinet and too small, so these subs sound the same way both front and back! I was thinking of building two new cabinets and came across the cube 15 project.
the features of my sw540 sub are:
MOSFET amplifier (class AB)
Max. Output power 550 watts continuous rms 850 max peak
Frequency Response 38Hz ÷ 120Hz ± 1dB
impedance 4ohms
Stereo electronic crossover 24dB / octave Crossover frequency 120hz

I think the woofer is from B&C but you don't know the model! however i found some specifications of this woofer in the manual.
Nominal diameter 15 "
Frequency range 37 ÷ 2000Hz
Sensitivity 99db
Rated impedance 4 ohms
Net weight 8 kg
FS 37hz
RE 3.04 Ohms
Qms 16.93
Qes 0.35
Qts 0.34
Vas 0.1m3
ηo 3.17%
B.l 16.62 T / m
SD 0.085m2
Xmax ± 5.25mm

Cubo15 replied the topic:

#25003

2 years 5 months ago

Both the STX W.38.1200.8.MC and W.38.800.8.MC look good on paper, except one thing, the weight of the drivers doesn't correspond to such T/S-parameters: Normally you wouldn't use the physical weight of a driver to base it's performance on, but since all these drivers have ferrite magnets and from the looks of the photo's also have aluminium baskets, you would expect better overall performance with an increasing physical weight.

The 1508-8 SPS BWX for example, weighs 7.7 kg but it has a high-ish Qes (less magnet needed) and small Xmax (4.7 mm again less magnet needed), so those numbers add up.
The Kappa Pro 15LF, weighs 10 kg, has a medium Qes and Xmax, and a 3" voice coil instead of a 4" voice coil like the Black Widow has. Again those numbers add up.

The STX W.38.1200.8.MC, weighs 7.5 kg, (claims a large voice coil and Xmax, medium Qes) and the T/S-parameters suggest it would would be close in performance to the 15TBX100, however the 15TBX100 (also large voice coil and Xmax, medium Qes) weighs 12.3 kg.

So something is off, as I'm rather safe than sorry, I would exclude the STX drivers from the list.

1) Kappa Pro 15LF
2) Black Widow 1508-8 sps (or the Kappa 15LF, 9 kg but a steel chassis)

Cubo

nemsik replied the topic:

#25001

2 years 5 months ago

Hello Oskar,
I have used two "W.38.800.8.MC" from two different series and I think they are quite weak speakers, so I don't know if the "W-38-1200-8-MC" will be much better.
Currently, I have loaded 15TBX100 and the difference is big.

oskarociak replied the topic:

#25000

2 years 5 months ago

Hello Cubo.
Can you judge which of these speakers is best for the cubo 15?
a) Kappa pro 15 lf2
b) Black Widow 1508-8 sps
c) STX W.38.1200.8.MC
Thank you in advance for your answer

Zambrotta replied the topic:

#24992

2 years 6 months ago

but the one loaded with the 2226 is the meanest of them all thank you for the design brother

Zambrotta replied the topic:

#24991

2 years 6 months ago

ok thank you for your feedback Cubo I already have 3 x Cubo 15 extended two of them loaded with p.audio bm-15w and one with the p.audio p150/2226h and their spl is amazing....

Cubo15 replied the topic:

#24989

2 years 6 months ago

Hi Zambrotta,

That's a good driver for Cubo 15 Extended, only drawback is the short Xmax, therefor a 40 Hz high pass is advised.

Zambrotta replied the topic:

#24985

2 years 6 months ago

Hello Cubo I would like to try out the Cubo sub 15 but I only have a p.audio p150/2226 15inch driver that one with a blue basket at my disposal what are the chances of it doing well in that cabinet

Cubo15 replied the topic:

#24980

2 years 7 months ago

Hi,

It's 30 Hz vs 40 Hz. I''d go for Qts below ~0.4 and Xmax over 7 mm, if you elaborate your question, you'll get a more sophisticated answer

Zambrotta replied the topic:

#24979

2 years 7 months ago

Hello Cubo how are you...can you shed some light on the difference between the Cubo sub and Cubo 15....also what kind of drivers would work well inside the Cubo sub

Cubo15 replied the topic:

#24973

2 years 9 months ago

I do like the old 15PS100 over the newer 15PS100, I would place the old version on par with the 15G450N, while the newer version is on the bottom of the list, below the JBL, which in hindsight is a close second to the 15G450N.

nemsik replied the topic:

#24972

2 years 9 months ago

What do you think about B&C 15PS100 in Cubo15 extended?

Unfortunately but I found two different datasheets:
1) www.bcspeakers.com/en/products/lf-driver/15-0/8/15ps100-8 ("new")
2) images.thomann.de/pics/prod/260670_datasheet.pdf ("old")

Please tell me if "both" speakers are good for Cubo? Which will be better?

--edit--
I ask because the "old" 15PS100 has EBP = 100Hz but the "new" has only 82hz. The recommended value for Cubo is 100 or higher.
The "old" has QTS = 0.31 but "new" has 0.43, where recommended is 0.21 - 0.41
The "old" has VAS = 152 but "new" has only 103, where recommended is 150-300

The "new" 15ps100 is suitable for cubo15?

Thank you

giveortake replied the topic:

#24971

2 years 9 months ago

In the footnotes freespeakerplans.com/plans/14-plans/basscab/44-cubo15 the email has a mistake.

Thanks for this, I have now corrected the email and profile links.

nemsik replied the topic:

#24966

2 years 9 months ago

Thank you, I've emailed to you
In the footnotes freespeakerplans.com/plans/14-plans/basscab/44-cubo15 the email has a mistake.

Cubo 15

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