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Cubo Sub / Cubo 21

The largest cabinet from the Cubo series stands upon the edge of portabilty; To big to be compact, to compact to be big.

Like it's predecessors Cubo 12, Cubo 15 and Cubo 18 it's a stand-alone bass bin. It will equal or out run an 18" reflex cabinet from 30 Hz and up in terms of sensitivty*. Like all Cubo-designs it excels on the KISS-principle, with a single angled cut and a cut list from 1 and a 1/2 sheets of 244 x 122 cm / 8' x 4'.

Development

Based on Cubo 15 and Cubo 18, Cubo Sub is the 3rd prototype in a series of cabinets aiming at good reproduction down to 30 Hz. Mount the driver with the magnet in the horn for best low frequency reproduction from 30 Hz up to 100 Hz. With the magnet in the chamber for maximum output from 35 Hz up to 110 Hz.

Versions

Cubo Sub is optimized for single 15"/ 18" drivers**, and single 21" drivers, nicknamed Cubo 21. 

All 21" drivers will fit in the standard Cubo Sub but in that case care must be taken when pre-drilling the bolt pattern. Plans for Cubo 21 are available through e-mail (questionsaboutcubo at gmail dot com).

*        Measurement against BR18a tuned to 37 Hz

**      Due to reproducing sub frequencies 18" drivers with an Xmax of 7 mm or more are favoured. On average a 15" needs 1.5 times the excursion capabilities to produce the same output as an 18" driver or 2 times that of a 21" driver.

Acknowledgements

The designer likes to thank Xoc1 for his aid in the development process.

 

 

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 Download highest quality: Picture below / right click / save as.

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  Download highest quality: Picture below / right click / save as.

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Preliminary measurements can be found here: http://www.freespeakerplans.com/index.php?option=com_jfusion&Itemid=64&jfile=viewtopic.php&p=11555#p11555


Posted: 3 weeks 4 hours ago by Cubo15 #23168
Cubo15's Avatar
@m0gsia: I was talking about the Xmech, not the Xmax. The difference in Xmax is neglectable (as would 1 mm in Xmech difference be). If either the Void or the PD has say 5 - 10 mm more Xmech than the other, I would favour the one with the largest Xmech.
Those crazy drivers are basically the flagship drivers from most Europian brands (like RCF, 18Sound, B&C, Faital Pro, BMS, etc.). Typically 18" and 21" drivers with 5" VC with 1500 - 1800 W AES powerhandling, more Xmax than the Void and PD, much more Xmech (just in case) and a neodymium magnet to save your back ;)

Imho you don't need to go lower for PA-purposes then Cubo Sub delivers, scoops and mini-scoops might get there and might not, depending on the exact model you're talking about.

@SPL fanatic: For most BPH there are better choices but for anything that is ment as a true sub (such as Cubo Sub), the 18SW115 is a logical choice.

Best regards

Cubo
Posted: 3 weeks 2 days ago by SPL fanatic #23157
SPL fanatic's Avatar
Hi Cubo and friends :)

Is anybody here with real life experience with 18sw115 in cubo sub? I have 8 pieces and trying to figure out the best cabinet for them. The only thing I know now is BR is much more better for this speaker then folded horn and BPH. Actualy not works in BPH.

Hornresp data for Cubo Sub would be welcomed also.

thanks in advance
Posted: 4 weeks 1 day ago by m0gsia #23143
m0gsia's Avatar
Hey Cubo

Thanks for the reply. The support you give the community is amazing!

The void has 1mm less xmax but its 100gbp per driver less than the pd1850mk2 so I think this will be my choice.

Im curious what these crazy drivers for the sub are! Im in the uk but i can order from thomann.

Out of interest how do you think the cubo sub compares to a full size scoop and a mini scoop?

Cheers
Chris
Posted: 4 weeks 1 day ago by Cubo15 #23142
Cubo15's Avatar
My personal list from best to least, would probably be PD1850, V18-1000 (depending on which one has the highest Xmech), then the Fane Colossus 18XB. For Cubo 18 Extended the PD.1850 mk1 or V18-1000 would be one of the greater drivers out there, for Cubo Sub there's a bunch of even heftier drivers out there but up to 1000 W of amplifier power these drivers will suffice.

Imo: Butt joints if you make a few, rebated joints if you make many.

Best regards

Cubo
Posted: 1 month 1 week ago by m0gsia #23122
m0gsia's Avatar
Hello Cubo,

I've built a pair of Cubo15s that I love but we need some more low end for dub music! So I'm looking at making the Cubosub

I've looked through the thread and cannot find the answer. How suitable are the following drivers in the CuboSub? Are Butt joints okay or are rebated joins necessary for this power level?

Void v18-1000 (my first choice)
Fane Colossus 18XB
PD 1850

Cheers
Chris
Posted: 1 month 3 weeks ago by Cubo15 #23082
Cubo15's Avatar
@ Dizz-E: You could use the 18SWS800 in Cubo Sub, though it isn't the toughest driver for that purpose. However if you're willing to raise the high pass to 35 - 40 Hz anyway, it would be better to build Cubo 18 Extended instead.

@Kasey: The 18SW115 can be used in both Cubo 18 or Cubo Sub, not sure which one you're referring too. In Cubo Sub for best low frequency response from 30 Hz and up. In Cubo 18 Extended for 35 - 40 Hz and up. Though usable in both designs the 18SW115 is a true sub woofer. You could also use normal reflex boxes, which would make most sense if you want the smallest cabinet. However output-wise one of the Cubo-designs would make more sense.

Best regards

Cubo
Posted: 2 months 2 hours ago by kasey #23078
kasey's Avatar
Hi Cubo, I have the opportunity to purchase a pair of B&C 18SW115 SUBWOOFERS. Will you recommend these to be used in the cubo 18? These are very high power neodymium subwoofers that I find have very good specifications.

Or should I just put them in normal reflex boxes? What do you think?
Posted: 2 months 1 day ago by DJ Dizz-E #23077
DJ Dizz-E's Avatar
Hi Cubo,
I currently have two 18SWS800. Would these drivers be safe to put in these cabinets since the Xmax is slightly lower than you recommend? Would they be safer if I'd raise the high-pass to 35-40hz?
Thanks!
Posted: 3 months 2 weeks ago by MAD #23022
MAD's Avatar
Thanks for the info, I will buy one or two and will post here my experience with the lf18x401.
Martin
Posted: 3 months 2 weeks ago by Cubo15 #23019
Cubo15's Avatar
If you can get the LF18X401 for about 250 Euro go for it, that's a gem of a driver by the way. For that money I doubt I could suggest anything better. It's like the Prime 18XS, it likes a lot of power but it's a true sub woofer.

Best regards

Cubo
Posted: 3 months 3 weeks ago by MAD #23015
MAD's Avatar
I don't know why, but I can not add the missing text above, new try:
Hi Cubo,
I'm new to this forum and plan to build 2-4 cubo sub 18 to add more low end to my system (my 4x 212 vented cabs have great kick bass and decent low bass, but below 50Hz there is something missing). Is the RCF lf18X401 a good choice or are there better choices in that price range (about 250 Euros her at Germany)? I've checked yiur recommendations to Geritass but these are all more expensive (my absolute limit is 300 Euro per speaker). I appreciate you not knowing the prices for all speakers here at Germany but I hope you can nevertheless suggest something...
Regards,
Martin
Posted: 3 months 3 weeks ago by MAD #23014
MAD's Avatar
Hi Cubo,
I'm new to this forum and plan to build 2-4 cubo sub 18 to add more low end to my system (my 4x 212 vented cabs have great kick bass and decent low bass, but below 50Hz there is something missing
Posted: 4 months 4 weeks ago by Cubo15 #22970
Cubo15's Avatar
The DD3500 series is primarily designed for use in small (automotive) enclosures. The 18" could be used in Cubo Sub but I would definitely try to mount it with the magnet in the chamber first for PA applications. Be sure you have at least about half an inch between the rear of the magnet and the inner part of the horn.

I think 30 -90 Hz is a safe bet, high excursion and a high crossover point usually are rivalry points for a driver.

Best regards

Cubo
Posted: 5 months 4 days ago by tj6006 #22949
tj6006's Avatar
Hi!

My first post here on the forum :)

I have a spare speaker, and i would like to use it for CUBO SUB.

Here is what I have:

Woofer Diameter 18" / 45.72 cm
Coil Diameter 3"
Fs 29 Hz
Qts 0.454
Qes 0.506
Qms 4.382
Vas 136.5 L
2-Way Suspension Travel 80mm
Cutout Diameter 16.75"
Mounting Depth 9.5"

Would this speaker work well?

I plan to use it as subwoofer, from 30-120hz (maybe just 30-90hz), driven with fp10.000.

Thanks a lot!
Posted: 7 months 1 week ago by Cubo15 #22836
Cubo15's Avatar
@T.geessounds: The 18NLW9601 is not the most efficient subwoofer, I would only recommend it if you have at least a solid 1500 W or more to feed it. In a Cubo 18 Extended it's about 2 dB less efficient than a Cubo 15 loaded with the Eminence Kappa 15LF. At full power it can rival with a double Cubo 15 loaded with the Kappa 15LF. If I had a 2000 - 2500 W amplifier it would be one of the few 18"driver choices for Cubo Sub.

@Geritass:

RCF: Cubo Sub: LF18X451 Cubo Sub and Cubo 18 LF18N451, LF18N401
18Sound: Cubo Sub and Cubo 18: 18NLW9601 (see above), 18NLW9000 Cubo 18: 18NLW9400
B&C: Cubo Sub: 18SW115, 18SW100 Cubo Sub and Cubo 18: 18NW100
Faital Pro: Cubo Sub: 18XL1600, Cubo Sub and Cubo 18: 18HP1020

All drivers will have similar low frequency response, maximum SPL will be mostly power related below 80 Hz. Choose the one with the biggest coil, for either Cubo Sub or Cubo 18, with most Xmax for Cubo Sub

Best regards

Cubo
Posted: 7 months 1 week ago by geritass #22833
geritass's Avatar
Hi, Cubo. may you recommend me the best subwoofer speaker for the CUBO SUB, and the CUBO 18 than reach the maximum Low frecuencie and maximum SPL (18sound, RCf, B&C, faitalpro)
thanks
Posted: 7 months 2 weeks ago by t.geessounds #22823
t.geessounds's Avatar
would the 18sound 18nlw9601 work well in the cubo sub??
Posted: 8 months 2 weeks ago by Cubo15 #22773
Cubo15's Avatar
@Valmiki77: I would use the 18SW3000 in Cubo Sub with the magnet inside the chamber. That way it will start to roll off somewhere around 35 Hz and be usable from 30 Hz and up. With the magnet inside the horn it will go a few Hz lower but at the cost of maximum output.

You could also build Cubo 18 Extended, which will be somewhere inbetween the Yorkie and Cubo Sub.

@t.geessounds: IIRC Valmiki77 already bought the 18SW3000 a few years back.

Best regards

Cubo
Posted: 8 months 2 weeks ago by t.geessounds #22769
t.geessounds's Avatar
valmiki77 wrote:
Cubo, do you think these prv's will cut it in the cubo sub?
www.parts-express.com/prv-audio-18sw3000...ofer-8-ohm--294-2755
How low do you think I'll get with them? I already have the subs in a Yorkie ls608 enclosure but I need to go lower than 50hz. These subs roll steep below 50. Help!

those speakers only have a xmax of 8mm and the spec some how always not right for that price u can get the 18sound lw2400 that work well in the cubo sub..
Posted: 8 months 2 weeks ago by valmiki77 #22766
valmiki77's Avatar
Cubo, do you think these prv's will cut it in the cubo sub?
www.parts-express.com/prv-audio-18sw3000...ofer-8-ohm--294-2755
How low do you think I'll get with them? I already have the subs in a Yorkie ls608 enclosure but I need to go lower than 50hz. These subs roll steep below 50. Help!
Posted: 11 months 2 weeks ago by Kvdb013 #22599
Kvdb013's Avatar
3 sheets -2 subs ;)
Posted: 11 months 2 weeks ago by Discosucks #22597
Discosucks's Avatar
Wow only seeing these for the first time now!

they look proper neat! and all from one sheet!!!
Posted: 11 months 2 weeks ago by Cubo15 #22593
Cubo15's Avatar
Those 18 1500's look the business, true sub drivers.

Ever heard of Cubo Kick 15, they stack nicely with Cubo Subs ;)

Best regards

Cubo
Posted: 11 months 3 weeks ago by Discosucks #22560
Discosucks's Avatar
Ok so im going to start work on 4 of these soon

I have 4 Fane colossus 18 1500's in my cbe's that i will be loading them with

The plan is to use 4 pd156 loaded es18's over them and my martin h3's ( will be changing the h3s for something , hopefully f1 res3's down the line) .

Should be a hard hitting system :)
Posted: 1 year 5 months ago by DJLink1 #21951
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Can't Seem to post pic on here but I posted pics and vid on my like page facebook.com/DJLinkone