Cubo 18:
Cubo 18 is a multi purpose, stand alone bass bin that, like Cubo 15, will equal or out run a single 18" BR*, of similar size, from ~ 40 Hz and up in terms of sensitivity. Cubo 18 works with a wide variety of 18” drivers. It has a cut list from just over a single 18 mm*** sheet (244 x 122 cm) / (8' x 4') with a single angled cut. Cubo 18" realizes a cost effective, small and light weight enclosure following the KISS-principle.
Development:
In 2007 the first prototype was build and tested. Cubo 18" is the 5th prototype in a line of hybrids aiming at the achievements as stated above.  Cubo 18 Standard and Cubo 18 Extended will both work with a wide variety of drivers, if uncertain which one will be most suited, build Cubo 18 Extended or mail me at This email address is being protected from spambots. You need JavaScript enabled to view it.
Size: 62x62x65cm (HxWxD)    
Frequency: From 40 Hz up to 110 Hz    
Enclosure Type: Hybrid

3D Model (by K-M-Sound-System):

 
Footnotes: 18” drivers preferably with an EBP of 100 or higher; Fs (22-42 Hz), Qts (0.25 - 0.58), Vas (200 - 450 L) / (7.4 – 16.7 ft^3). Where EBP = Fs / Qts . Measurements will follow.
 
Cubo 18/15 (difference): Cubo 18 is 3 cm (/ 1 1/6th inch) deeper then Cubo 15. Due to phase similarities Cubo 18 and Cubo 15 can be  used together without noticeable issues. Cubo 18 has on average slightly more output for a given input in comparison with Cubo 15 (based upon electro-mechanical relatively similar drivers), especially between Fc high and Fc low,whilst Fc high and Fc low, remain similar (= cut-off frequency).
 
 
 
 Cubo 18: Front view
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Cubo 18: Side view without side panel
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Cubo 18: Driver for comparison
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Cubo 18: Detail magnet and bracing
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Cubo 18: Magnet facing out
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Cubo 18: Magnet in chamber
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Cubo15's Avatar
Cubo15 replied the topic: #24596 1 month 2 weeks ago
Hi Hector,

The KC18-300C has a high Vas and medium Qes making it less suitable for small closed chambers, which explains the limited low end extension in the ES-18. 

Qts x Vas > 120, Cubo Standard
Qts x Vas = 100 - 120, Cubo Extended or Standard
Qts x Vas < 100, Cubo Extended

It's Qts x Vas product is near 170 making it a clear contender for Cubo 18 Standard. This 40 Hz should definitely be achievable, due to it's low Xmax of 5 mm, at high medium power levels a 40 Hz high pass is recommended.

Best regards Cubo
hectorberman's Avatar
hectorberman replied the topic: #24594 1 month 2 weeks ago
Hello Mr Cubo

I have a pair of Fane KC18-300C sat here and was wondering if they would perform best in the cubo 18 or extended version.
They are not very powerful drivers and I feel a  design like this is required to get the most out of them.
In the es-18 they sim ok down to around 55hz but I was hoping something like 40hz could be achieved. What do you think? 

Many thanks for your many contributions, Hector.
songatron's Avatar
songatron replied the topic: #24502 5 months 5 days ago
Great! Thank you as always!
songatron's Avatar
songatron replied the topic: #24501 5 months 5 days ago
AweDe
Cubo15's Avatar
Cubo15 replied the topic: #24499 5 months 5 days ago
First you would have to look at your tops, if you have horn loaded tops with a long enough horn path, you might actually have to delay the subs ;) Technically you're adjusting 33 cm (or about 1 ft.) of sound path difference for every millisecond of delay that you apply. Sound path differences depend on the exact design of the subs and tops but also spatial placement. The easiest way to set up delay is to play a sine wave, of the crossover frequency that you use, through your top and sub simultaneously. (in your case 90 Hz). This doesn't need to be played loud by the way.. If you reverse the polarity (red and black wire) on your subs, the best delay is the setting that reduces output to a minimum. Meaning that if you use the normal polarity during use, the sub and top will have maximum output at the crossover frequency.

40 - 90 Hz sounds like a good setting in combination with 1200 W if kept away from clipping at all times. Boosting 40 Hz with EQ, while also using a 40 Hz high pass isn't going to be very effective for boosting low bass. I would initially lower the high pass if you feel the E-18ELF does have enough excursion left (somewhere between 30 - 35 Hz). If you truly need more low end you can consider building a Cubo Sub instead or adding one to your current setup..

Best regards Cubo
songatron's Avatar
songatron replied the topic: #24498 5 months 6 days ago
Hello!

I have a Cubo 18 loaded with a:
P-Audio E-18ELF - 18" 800W
I have two questions:

- What (if any) delay should I put on my mid/top section? I've read though lots of posts and can't see any reference to horn length/necessary delay.

- I have it crossed at 40hz- 90hz. Does that sound right? I'm working with someone who likes/is fussy about 'real' low end... Could I go any lower than 40hz? I guess not. Could I boost 40hz through EQs on my DSP, if I dont push the driver that hard would this be ok? I'm running it with a QSC RMX1850 in bridge.



Thanks!
Cubo15's Avatar
Cubo15 replied the topic: #24493 5 months 1 week ago
Hi,

The PD184C01 and Fane 18XB are quite similar in many ways (gap depth, voice coil overhang, Vas x Qes product). The main difference is the higher EBP and efficiency on the Precision Devices which makes it a bit more Cubo 18 oriented while the Fane XB is a bit more Cubo Sub oriented. However, because of the similarities in excursion they will both have similar performances in Cubo Sub as well as Cubo 18 (Extended for both). I expect the PD will pronounce the upper frequencies a bit (around 80 Hz) and thus the lower kick, while the Fane will sound a bit warmer and more subby.

So the PD184C01 in Cubo 18 for maximum output and the Fane in Cubo Sub for maximum sub oriented response. However swapping the drivers will also work.

Cubo
SBSoundSystem's Avatar
SBSoundSystem replied the topic: #24492 5 months 1 week ago
Hi Cubo,

I have a PD184C01 driver or a Fane 18XB, which do you you think would be better in Cubo 18 or Cubo Sub?
I am aiming for good low end bass.

Thanks
Cubo15's Avatar
Cubo15 replied the topic: #24447 9 months 2 weeks ago
Personally I favor lower Qes drivers in Cubo 18 Extended, so the 18PZB100 (ferrite, decent power handling), the 18NW100 (neo, high power handling) or the 18DS115 (cost no object, very high power handling). Considering you already have Cubo Subs, the 18DS115 might be a bit much.

Best regards Cubo
capicva's Avatar
capicva replied the topic: #24444 10 months 2 days ago
After building 3 Cubo Sub's, which I love, I want to build a couple of Cubo 18's for the "portability" advantages. I scrubbed the thread but could not find recommendations of B&C drivers.  Cubo, what would you recommend from the currently available 18" B&C drivers (  www.bcspeakers.com/en/products/lf-driver ) ? Thanks.
sweetvibes-inc's Avatar
sweetvibes-inc replied the topic: #24443 10 months 4 days ago
Hi there Mr Cubo,

Please excuse me for the delay in replying to your response and thank you so, so much with all your help regarding the baffles and bolt holes.

In the end I made a double baffle and only used two of the four Cobo 18's with two specially adapted smaller cubo 15" cabs in a medium sized hall  (they ROCKED and Tore the place down OMG happy days)

A friend of mine has finally completed building his Cubo 18's (hearing mine recently has given him a push) he would now like to extend them like mine. Can he place the 18cm extension board in the cab now the cab has been built or will he have to make new cabs. 

Like you suggested in the last thread "Because the RCF RCF LFX451 has good Xmax you can use o bit of EQ to get most out of
it but if you need much deeper bass Cubo Sub might be a better option for it"  therefore I am now thinking about building some Cubo Subs to add to the arsenal but; I do not have a workshop, the weather is not so wonderful to build outside now and I am running out of time so, I'm considering buying some Mini Scoops, do you think there will be any compatibility issues?

Many thanks,
Sweetvibes-inc
Cubo15's Avatar
Cubo15 replied the topic: #24425 10 months 4 weeks ago
Did you try the Fane with the magnet visible or magnet inside the chamber? That orientation has some influence on how deep the driver goes in Cubo 18 Extended, although most of it is due to Cubo 18 itself and not the driver. The RCF LFX451 is a good sub driver so it might change how deep it goes a bit but not by much. Because the RCF has good Xmax you can use o bit of EQ to get most out of
it but if you need much deeper bass Cubo Sub might be a better option for it.

I usually make a 18 - 30 millimeter ring on the baffle that has two sets of bolt patterns in it. It has 8 t-nuts for the new driver and spaced in the middle between those holes, 8 clean holes for the old driver. The ring is then mounted onto the baffle using hex bolt countersunk heads, so the ring surface is flush. The new driver can then be mounted with short bolts via the t-nuts. I like to countersink the t-nuts a bit, so that the entire bolt threat is used before exerting maximum (bolt clamp) force on the threat. The bolts are 17 - 29 mm plus whatever extra length is need for the driver, so they don't touch the baffle of the Cubo, this means they might need to be cut to length.

I've seen those clamps used before on heavy drivers, although I've never used them, they seem capable. So if implemented the right way that could be an relatively easy fix.

Best regards Cubo
sweetvibes-inc's Avatar
sweetvibes-inc replied the topic: #24419 11 months 4 days ago
Hi There Mr Cubo,

I am wondering if you can help with this problem.

I have four Cobo 18 extended that were loaded with FaneXB's 1000w 8ohm they were ok but the bass was not quite deep enough so,
I have now upgraded to RCF LFX451- 18" 1800w 8ohm. The problem is the bolt pattern and the cut out hole are very different therefore; I may have to use clamps instead of m6 bolts and T-Nuts not having enough space to get a router and a drill in the cab to work on the baffle. Can I place another baffle on top of the existing one and what difference will it make to the performance and sound quality.

Mounting information: RCF LFX451
Overall Diameter: 465 mm / 18.3 inch
Bolt Circle Diameter: 442-447 mm / 17.4-17.6 inch
Bolt Hole Diameter: 6.5 mm / 0.25 inch
Front Mount Baffle Cut-out: 424 mm / 16.7 inch
Rear Mount Baffle Cut-out: 424 mm / 16.7 inch
Depth: 194 mm / 7.63 inch

MOUNTING Fane XB
Overall Diameter 19.1" / 485 mm
Width Across Flats 18" / 457 mm
Flange Height 0.465" / 11.8 mm
Baffle Hole Diameter F/M 16.52" / 420 mm
Baffle Hole Diameter R/M 16.33" / 414 mm
Fixing Holes 8x 0.275" diam on 18.425" PCD
8x 0.275" diam on 17.25" PCD
8x 7 mm diam on 468 PCD
8x 7 diam on 438.15 PCD
Depth 8.07" / 205 mm

Thanks in advance and I look forward to hearing from you,

Sweetvibes-inc
sweetvibes-inc's Avatar
sweetvibes-inc replied the topic: #24418 11 months 4 days ago
Hi There Mr Cubo,

I am wondering if you can help with this problem.

I have four Cobo 18 extended that were loaded with FaneXB's 1000w 8ohm they were ok but the bass was not quite deep enough so,
I have now upgraded to RCF LFX451- 18" 1800w 8ohm. The problem is the bolt pattern and the cut out hole are very different therefore; I may have to use clamps instead of m6 bolts and T-Nuts not having enough space to get a router and a drill in the cab to work on the baffle. Can I place another baffle on top of the existing one and what difference will it make to the performance and sound quality.

Mounting information: RCF LFX451
Overall Diameter: 465 mm / 18.3 inch
Bolt Circle Diameter: 442-447 mm / 17.4-17.6 inch
Bolt Hole Diameter: 6.5 mm / 0.25 inch
Front Mount Baffle Cut-out: 424 mm / 16.7 inch
Rear Mount Baffle Cut-out: 424 mm / 16.7 inch
Depth: 194 mm / 7.63 inch

MOUNTING Fane XB
Overall Diameter 19.1" / 485 mm
Width Across Flats 18" / 457 mm
Flange Height 0.465" / 11.8 mm
Baffle Hole Diameter F/M 16.52" / 420 mm
Baffle Hole Diameter R/M 16.33" / 414 mm
Fixing Holes 8x 0.275" diam on 18.425" PCD
8x 0.275" diam on 17.25" PCD
8x 7 mm diam on 468 PCD
8x 7 diam on 438.15 PCD
Depth 8.07" / 205 mm

Thanks in advance and I look forward to hearing from you,

Sweetvibes-inc
Cubo15's Avatar
Cubo15 replied the topic: #24393 1 year 1 month ago
Those 3 are all in the same league (Cubo 18 Standard drivers) but I would start with the 3rd option

Best regards Cubo
disco's Avatar
disco replied the topic: #24392 1 year 1 month ago
hello) what will fit the best? there is 18" 1- fs32 re6,8 qms 12,2 qes0,35 qts 0,339 vas443l mms123g bl21,4 windight deptn 8mm coil 22mm cms0,27
2- fs 27hz qts0,25 qes 0,26 qms5,4 vas620 sd1288mm bl20,3 coil height20mm depth8mm
3- fs31 qts0,28 qes0,30 qms 7,1 vas430l sd1288 cms 0,16 coil20mm depth8mm bl23
Cubo15's Avatar
Cubo15 replied the topic: #24381 1 year 2 months ago
Hi,

Efficient speakers (like the 2241G) often excel in Cubo's, with a slight rising response, that will give them near the same output as (the same driver in) a double 18" reflex cabinet. Cubo's are strong at 50 - 80 Hz, which is were most energy in almost all music is, they do go lower though.

Best regards Cubo
puffah's Avatar
puffah replied the topic: #24378 1 year 2 months ago
  • Hi Hi ma
Hi my name is nathan. I have 8 of the old jbl sr single 18 subwoofer boxes. the jbl sr4718. They kind of are more of a midbass box then a sub. I wanted to pull the drivers and find a better box that might make them more boomy in the low end. I know its a good driver in a bad enclosure. Has anyone used the jbl 2241g subwoofer in these cubo 18 boxes. Any idea how they would sound or if its a good idea/match with this driver. Thanks nathan
Cubo15's Avatar
Cubo15 replied the topic: #24365 1 year 3 months ago
Yes,You might theoretically 1 or 2 Hz extension but practically this isn't ever reported as a problem.Best regards Cubo
t.geessounds's Avatar
t.geessounds replied the topic: #24364 1 year 3 months ago
www.parts-express.com/lavoce-san18402-18...oofer-8-ohm--293-729

also can i get away building the cubo 18 570mm wide? need them to fit in my car
Cubo15's Avatar
Cubo15 replied the topic: #24363 1 year 3 months ago
Hi, is that a new brand?

The 184.03 should work well in Cubo 18 Extended and Cubo Sub.

Best regards Cubo
t.geessounds's Avatar
t.geessounds replied the topic: #24361 1 year 3 months ago
hn

can the LaVoce San 184.03 
18" neo work well in the cubo ex well?
thanks
Cubo15's Avatar
Cubo15 replied the topic: #24268 2 years 1 month ago
The box 18/500 is one of the best 18" budget drivers out there (for Europe), it even has some specs (like the 4" VC and the aluminium chassis) that are usually indicators that it isn't in fact a budget driver. Where it does go wrong (although for its selling price you can't blame them), the 18LW2400 goes right, putting itself in a class above the 18/500,

So 6 vs 8 each with their respected power handling sounds fair. For the 18/500 I would go for 500 - 700 W per driver, with the 18LW2400 I would look at 750 - 1250 W.

Best regards Cubo
Swanndog's Avatar
Swanndog replied the topic: #24265 2 years 1 month ago
Can you advise if the Thomman the box 18/500 speaker would be a good choice for a budget option for the cubo 18 extended ?
Details here images.thomann.de/pics/atg/atgdata/docum...85008a_uk_screen.pdf

I have previously used the 18 sound 18lw2400 and was super impressed with the results when using 6 in a mono stack. I now have 8 unloaded cabs but do not have the budget for 8x 18lw2400. Would you suggest having 8x the box 18/500 loaded cubo18 would be comparable to 6 x 18lw2400 ? Or would it be better to save a little more £ and go for 6x 18lw2400 that i have had before and i know works well ? More is not always better so im led to believe
Thanks in advance
Cubo15's Avatar
Cubo15 replied the topic: #24223 2 years 3 months ago
It is possible to add the Extended piece after building a Standard. It will be a bit of an operation though, so if you're happy with the sound as of now, I would think twice before fixing it. Remember that the Extended piece is an optimisation rather than a necessity, so EQ can be a viable alternative indeed.

If you have made no alterations to the large triangular bracing in any way, I would add the Extended panel in 2 parts/ pieces. One from the left wall to the bracing and one from the right wall to the bracing. I would dry-fit the pieces to make sure they're a snug fit and get all the dirt and dust from anything the glue will touch. Then using a 1-component, filling PU tix (like: www.bisonprof.nl/nl-nl/producten/715-hou.../product/312-pu-tix/ ) spread out on both the enclosure walls, as well as the pieces to be fitted. I would use something like a piece of wood (or a nail gun) to support it in it's place while drying.

Alternatively, you could take out a part of the bracing with a jigsaw, then place the Extended bit in one piece. If you add wooden corner blocks to the Extended panel, you can use short screws and glue to add it from the inside.

Best regards Cubo