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: 3 weeks 2 days ago by Cubo15 #21576
Cubo15's Avatar
@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: 3 weeks 2 days ago by Cubo15 #21575
Cubo15's Avatar
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: 4 weeks 2 days ago by deejay skillz #21548
deejay skillz's Avatar
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: 1 month 14 hours ago by gfoster #21540
gfoster's Avatar
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: 1 month 3 days ago by Cubo15 #21517
Cubo15's Avatar
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: 1 month 1 week ago by greg32 #21504
greg32's Avatar
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: 1 month 2 weeks ago by Cubo15 #21469
Cubo15's Avatar
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: 1 month 4 weeks 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: 2 months 4 days ago by Cubo15 #21431
Cubo15's Avatar
@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: 2 months 1 week ago by deejay skillz #21416
deejay skillz's Avatar
Hi Cubo,

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

Best Regards
Skillz
Posted: 2 months 2 weeks ago by t.geessounds #21403
t.geessounds's Avatar
cant i build these 77 x 54.5 x 77 ?
for the speakermax speakers WF18THOR
www.speakermax.com/pages/woofer.html
Posted: 2 months 2 weeks ago by Cubo15 #21397
Cubo15's Avatar
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: 2 months 2 weeks ago by deejay skillz #21370
deejay skillz's Avatar
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: 4 months 1 week ago by Cubo15 #20907
Cubo15's Avatar
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: 4 months 3 weeks ago by YuriyZhan #20874
YuriyZhan's Avatar
Hello Cubo! What is the sensitivity of this cabinet in the band from 40 to 100? You measured the spl instrument?
Thank you!
Posted: 7 months 1 week ago by Kvdb013 #20545
Kvdb013's Avatar
t.geessounds wrote:
so did u follow the cubo sub plans??
an this is your external---77cmx62cmx77cm??

Yes, i build the subs exactly like the plan!
Posted: 7 months 2 weeks ago by t.geessounds #20539
t.geessounds's Avatar
so did u follow the cubo sub plans??
an this is your external---77cmx62cmx77cm??
Posted: 7 months 2 weeks ago by Kvdb013 #20532
Kvdb013's Avatar
And some pictures from the end result.

criticism and coments are welcome.



















thanks to Johan Rademakers

Best regards

Koen van den bersselaar

(sorry for my bad english, i'm from holland!)
Posted: 7 months 2 weeks ago by Kvdb013 #20530
Kvdb013's Avatar
Last week I started to build two cubo subs.The speakers I use are the faital pro 18hp1030.

Here are some building pictures.

Criticism and comments are welcome.




























Posted: 9 months 3 weeks ago by Cubo15 #20230
Cubo15's Avatar
Hi (not sure how to read your name), that's good to hear. Good luck!

Best regards

Cubo
Posted: 10 months 17 hours ago by ldimebagl #20210
ldimebagl's Avatar
Thank you Mr. Cubo! mi pair of 18LW1400 sounds GREAT in CUBO SUB!! mi old front reflex cases sucks.
Posted: 2 years 3 months ago by Cubo15 #16264
Cubo15's Avatar
Hi Martin,

Thanks for that explanation.

Unless however some significant changes have been made between 28.7 and 28.9, personally I would still be inclined to use WinISD Pro for (about just) that purpose.

Call me old fashioned but my mind needs several time periods to adjust between WinISD's all-is-smooth-and-round and Honrresp's all-is-very-peaky responses. Measurements have shown me the result is often in between...

I know that 30 m/sec is an actual good guideline for PA-purposes and 17 m/sec is a good guideline for home applications in WinISD Pro. I do believe that these exact figures need to be re-evaluated for HR.

Luckily I'm experimenting with a ported Cubo enclosure at the moment so I'll have time to evaluate ;)

Best regards

Cubo
Posted: 2 years 3 months ago by Xoc1 #16244
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Cubo15 wrote:
You can read this guide to WinISD and Hornresp for starters. If going the reflex route you'll need WinISD Pro for telling you the air velocity in the port.
Best regards
Cubo
Hi Cubo, Hornresp is now capable of simulating the port velocity.
From the SPL response window, then select the Combined Response from the Tools menu, and enter a blank, for the port only output.
When the Port SPL response is displayed, then select Particle Velocity from the Tools menu.
WinISD is a good start and easy to learn but Hornresp is capable of more accurate results.
A comparison of WinISD and Hornresp here,
http://forum.audiopsychosis.com/viewtop ... 79&start=0
I am now using Hornresp for all my reflex port designs. smiley20
Regards Xoc1
Posted: 2 years 3 months ago by Cubo15 #16233
Cubo15's Avatar
You can read this guide to WinISD and Hornresp for starters. If going the reflex route you'll need WinISD Pro for telling you the air velocity in the port.

A double SDX10 in a tapped horn sounds as a good plan to me ;)

Cubo Sub will do litlle below 30 Hz without extension or EQ.

Best regards

Cubo
Posted: 2 years 3 months ago by jimmy154 #16216
jimmy154's Avatar
Oh boy. I'm confused, look
> smiley29 or maybe like this also
> smiley24 and perhaps a little :think:

I think I will have to figure out how to use Hornresp and maybe model some ported enclosures also. I need a horn that is roughly 1215 x 510 x 770 mm. If it's shorter than 1215 mm I think my kids will get on it and then on my main speakers and then my computer and tv and etc. Or bass relfex might be good also. I like how the cone excursion is limited at tuning, but I don't like the way they sound. I have read that when designed right they sound just as good as a sealed with a Qtc at or near .5, but I haven't hear one that is as good.