Free Speaker Plans

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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: 1 week 1 day 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
Posted: 4 weeks 1 day ago by cvbaudio #21903
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Dear Cubo

I have 2 18sound 21LW1400 and are looking for a good building plan

Thiele Small Parameters
Fs 28 Hz
Re 5Ohm
Sd 0,1662 sq.mt. (257,6 sq.in.)
Qms 9,32
Qes 0,242
Qts 0.235
Vas 385 lt. (13,6 cuft)
Mms 296 gr. (0,65 lb)
BL 33,5 Tm
LinearMathematical Xmax ± 9,5mm(± 0,37 in)
Le (1kHz) 2,85mH
Ref. Efficiency 1W@1m(halfspace) 98,0 dB


Would the CUBO SUB be suitable ?

If so Could you please send me the plans
Posted: 1 month 11 hours ago by Cubo15 #21871
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Picture or it didn't happen ;)

Best regards

Cubo
Posted: 1 month 1 week ago by DJLink1 #21866
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Hey just built my first pair cubo sub tested them today and I am speechless. Shook everything in my house. Just need to do cosmetics and they are good to go.
Posted: 1 month 1 week ago by ldimebagl #21856
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yes, is compact but powerful,18Sound logos I made myself with a photo color and epoxy resin ;) once again, thank you for this design Cube!
Posted: 1 month 1 week ago by Cubo15 #21853
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That must be a small but powerfull system, where did you get those 18Sound logo's from? I think they're kinda cool.
Posted: 1 month 2 weeks ago by ldimebagl #21836
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Now...here my sound system,18Sound 18LW1400,18Sound 12MB600,B&C DE250

Posted: 2 months 18 hours ago by Cubo15 #21803
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You can upload to: www.imagevenue.com/ and post a link or thumbnail.

Best regards

Cubo
Posted: 2 months 1 day ago by ldimebagl #21802
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I can not post pictures
Posted: 2 months 1 day ago by ldimebagl #21801
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Here my sound system,18Sound 18LW1400,18Sound 12MB600,B&C DE250
Posted: 4 months 3 weeks ago by Cubo15 #21576
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@Gfoster: I do not have a list of suitable drivers other than the drivers mentioned in this thread. If you want to know if a particular driver is suitable, you can either ask in this thread or e-mail me at questionsaboutCubo[at]gmail[dot]com.

I expect a list to appear in the future, so that the plans get more self-sustained.

Best regards

Cubo
Posted: 4 months 3 weeks ago by Cubo15 #21575
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This graph shows the difference between different Cubo Sub prototypes either with the magnet in the chamber (MIC) or magnet in the horn (MIH). As can be seen, MIH gives the most output down low, while MIC gives the most output from ~ 50 Hz and upwards. This can be both measured and heard as a notible difference.

www.freespeakerplans.com/media/kunena/at...Cubo%20Sub%20123.PNG

Cubo Sub 1, 2 and 3 are the first to third prototype respectively, all with an 18" driver. Different drivers can be best viewed as a single driver with larger or smaller Sd. Larger Sd will often, though not always increase output around 60 - 80 Hz.

Best regards

Cubo
Posted: 5 months 4 days ago by deejay skillz #21548
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Hi cubo, I don't know if I got it right from the preliminary results posted i.e the cubo sub 18 magnet in chamber gives most around 60hz?. An index would be ideal. a quick guess subject to confirmation here we go....cubo sub 1 ( double15 inch version ) cubo sub 2 ( 18 inch version ) cubo sub 3 ( 21nch version )

Best regards
Skillz
Posted: 5 months 5 days ago by gfoster #21540
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Hi, I am looking to build the Cubo sub, what difference do you get with the driver in the chamber or outside showing? also do you have a list of drivers suitable?

Gareth
Posted: 5 months 1 week ago by Cubo15 #21517
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I think all Cubo models can be used together, up to the point of certain boundries. For example if you can physically seperate them, say the Cubo 15 left and right and Cubo Sub in a centerstack, that would always have my personal preference. If you're gonna mix them in a single stack, I don't necessarly expect trouble but since there are so many variables you never know for sure. If you're going to use the same high pass for both I would make it as high as possible and steep.

The thing with the JBL of course is that it's more of a bass driver than a sub driver, Xmax is speced as 5.5 mm, T/S-parameter-wise it will work but the mechanical power handling will be less than optimal.

Best regards

Cubo
Posted: 5 months 1 week ago by greg32 #21504
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hi Cubo, how would cubo15 and cubo sub behave together? I remember reading that the cubo18 and cubo15 could be used together, im thinking of building cubo sub pair for jbl 2240 as I have a few of these? any issues? best regards Greg. (still love the cubo15!)
Posted: 5 months 3 weeks ago by Cubo15 #21469
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High pass @ 30 Hz (bit lower is possible but doesn't do much output-wise), 12 - 24 dB/ octave BW (LR as a last resort). Low pass average at 80 Hz, 24 dB/ octave LR.

Best regards

Cubo
Posted: 6 months 3 days ago by ldimebagl #21442
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Hello mr Cube! I have a couple of 18LW1400 in CUBO SUB and DCX2496, what would be the recommended cut?

Thank you!
Posted: 6 months 1 week ago by Cubo15 #21431
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@T.geessounds: It doesn't seem to mention any of the Thiel/ Small parameters anywhere. For a 4" VC, 120 oz. magnet 18" driver, I expect it to work but absence of T/S-parameters is usually not a very good sign.

Reducing the width of Cubo Sub like that will raise the lower usable frequency up by 3 - 4 Hz, making it a more or less 34 Hz and up cabinet.

@Skillz: You can mix them (on the crossover) but in that case I would prefer physically seperating them. Say the Cubo 15 left and right and Cubo Sub in a centerstack. If you're gonna mix them in a single stack, I don't necessarly expect trouble but since there are so many variables you never know for sure. If you're going to use the same high pass for both I would make it as high as possible and steep.

Best regards

Cubo
Posted: 6 months 2 weeks ago by deejay skillz #21416
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Hi Cubo,

Can you mix cubo sub (magnet in chamber) with cubo 15 ( magnet in chamber)

Best Regards
Skillz
Posted: 6 months 2 weeks ago by t.geessounds #21403
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cant i build these 77 x 54.5 x 77 ?
for the speakermax speakers WF18THOR
www.speakermax.com/pages/woofer.html
Posted: 6 months 2 weeks ago by Cubo15 #21397
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There is little difference in the throw between a Cubo Sub and Cubo 18, though Cubo Sub is slightly better in that department. Cubo Sub will drop lower (usable from 30 Hz and up, for that very lowww-sound), Cubo 18 is more allround from 40 Hz and up but more compact.

Best regards

Cubo
Posted: 6 months 3 weeks ago by deejay skillz #21370
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Hi Cubo!. which cab is gud for outdoor cubo 18 sub or cubo 18. what are the difference when using a fane xb 18.Thanks
Posted: 8 months 2 weeks ago by Cubo15 #20907
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This measurement is compared to a 18" reflex tuned to 37 Hz.

www.freespeakerplans.com/kunena/38-hoste...bo-18?start=40#11555

Hornresp simulates sensitivity as 100 - 102 dB/W/m dependant on the driver used.

Best regards
Posted: 8 months 3 weeks ago by YuriyZhan #20874
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Hello Cubo! What is the sensitivity of this cabinet in the band from 40 to 100? You measured the spl instrument?
Thank you!