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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Nugget's Avatar
Nugget replied the topic: #24680 1 month 1 week ago
I am sorry for answering so late, i had holidays. Reason for the Cubo 15 ext. with bigger cutout was just that this one was already built and usable as a test cab.
I have not compared Cubo 18 to BR with the same driver, because both were measured by a friend who lives some 100 kms away from me. But i really do like my Cubo 15s with Kappa LFA. Because of the lower need of xmax, they tend to sound a little more effortless compared to BR. The other notable thing is the higher part of 2nd harmond distortion compared to 3rd, while measured BR gave more 3rd than 2nd. In my experience that leads to a "warmer" sound. Only downside is, that my Cubo 15 with Kappa LFA and the Cubo 15 ext. with Colossus both had -3db points at 47 hz which isn't too low. But it's right that they tend to "sound lower". The -3db Point on LF18N401 was about 43,5 hz btw.
Cubo15's Avatar
Cubo15 replied the topic: #24679 1 month 1 week ago
That sounds good, are you or when will you be able to give a sneak peek?
bee's Avatar
bee replied the topic: #24675 1 month 1 week ago
all good m8t, had ishues loggin in for a while, but ill try posting a bit more. Got a great free plan in the works, working along side mmj in the usa. proto should be finished in the next week.
Cubo15's Avatar
Cubo15 replied the topic: #24671 1 month 2 weeks ago
Measuring T/S-parameters is always wise, can also be done in REW if you can get it to work for you.  The V15-700n is used in a reflex and band pass bass cabinet, so that will typically mean it's either (most) suitable for Extended or Extra Extended.
Djspinback69's Avatar
Djspinback69 replied the topic: #24669 1 month 2 weeks ago
Found this on the internet posted on Amazon by Void. Apparently this is the driver from the Arcline x and the Basys system
Djspinback69's Avatar
Djspinback69 replied the topic: #24667 1 month 2 weeks ago
I’d also quite like to have a go at measuring the T/S parameters of them
Djspinback69's Avatar
Djspinback69 replied the topic: #24666 1 month 2 weeks ago
It’s not something I’ve done before but keen to give it a go and see how they perform vs my fane reflex cabs and the fane in the Cubo’s

ive attached a couple more pics of the driver. The cone is really rigid
Cubo15's Avatar
Cubo15 replied the topic: #24665 1 month 2 weeks ago
I use REW (Room EQ Wiizard) nowadays for measuring, never tried it on Mac but the OS is supported. If you haven't used the V15-700n yet, the low frequency response tends to approve in the first ~10 hours of use.

@Bee: Good to see you're still around! How's life?

Cubo
Djspinback69's Avatar
Djspinback69 replied the topic: #24664 1 month 2 weeks ago
It’s definitely not a V1000 it’s 15” it’s a V15-700n which is the driver out of something like a Arcline 2 x 15” not sure on the cab I used to be able to find it on Google but not now
bee's Avatar
bee replied the topic: #24663 1 month 2 weeks ago
do you no what void driver model it is. the  v1000 is the most common. A few others do exist.
Djspinback69's Avatar
Djspinback69 replied the topic: #24657 1 month 2 weeks ago
That’s great, thanks for taking the time to reply to me. It’s very much appreciated. That’s pretty much what I was thinking. I’ve attached a pic of the void driver screwed into my mdf test cab. Can’t tell you much about it other than it looks like a neo driver, the cone looks very stiff and it looks like it means business and I’m sure it’s 700W will be an interesting experiment. I’ve just bought a measurement mic and a interface for my MacBook so if I can work out how I’ll take some readings??
other than that I think I’ll order an RCF driver and A/B them all 
Cubo15's Avatar
Cubo15 replied the topic: #24654 1 month 2 weeks ago
I've had some great reviews from people using drivers like the LF18N401, it does give a bit smoother response than the Prime and a slowly rising response. Lower efficiency drivers like the Prime really need some power to get loose in my experience. The extra Xmax of the Prime does allow a bit of EQ, typically in the 40 - 65 Hz region.

IIRC Nugget did first build a Cubo 15 Extended and based on simulation Cubo 18 only drops 3 Hz lower then Cubo 15, he's not the first to convert a Cubo 15 to Cubo 18 that way.

AFAIK Void only released 2 or 3 drivers for the DIY-community, all their other drivers are strictly for their own cabinets, it's unlikely you'll find T/S-parameters for them. That makes it hard to say how they'll perform in Cubo 15, although they will have to be pretty weird not to work and considering we're talking Void Acoustics here I'm pretty sure they'll be quality drivers.

Cubo
Djspinback69's Avatar
Djspinback69 replied the topic: #24653 1 month 2 weeks ago

Cubo15 wrote: Djspinback69 Well, I wasn't going to show the measurements but was pretty much going to answer based on those measurements.

Nugget How did you like the sound of your 'Cubo 18's' compared to the reflex?

Cubo


I am a bit confused by your reply Cubo, I haven’t asked for any measurements only guidance with driver choice
Djspinback69's Avatar
Djspinback69 replied the topic: #24652 1 month 2 weeks ago
Hi Cubo

i don’t really need the measurements. Only some guidance on whether the fane 18xs or RCF drivers will work well?

i also note that Nugget fitted them in a Cubo 15 Ext with bigger cuttout. Any reason why? I ask because I’ve just built one to test with some 15 inch drivers I have here. 

not sure of their history but they’re Void V15-700n I think?? They’re out of something like a 2 x 15” arc line of something. I’m not really sure and can’t find the cab on Google any more
Cubo15's Avatar
Cubo15 replied the topic: #24651 1 month 2 weeks ago
Djspinback69 Well, I wasn't going to show the measurements but was pretty much going to answer based on those measurements.

Nugget How did you like the sound of your 'Cubo 18's' compared to the reflex?

Cubo
Nugget's Avatar
Nugget replied the topic: #24649 1 month 2 weeks ago
Funnily i have a measurement with LF18N401 vs Colossus Prime 18XS in Cubo 15 extended (with larger driver cutout). If you send me your eMail adress via PN, i will send you the graphs.
Djspinback69's Avatar
Djspinback69 replied the topic: #24647 1 month 2 weeks ago
Hi Mate,

How’s it going. Hope you don’t mind asking a couple questions about the Cubo18

I currently have a pair of reflex subs loaded with fane18xs the enclosure is the one on the fane website. I need some more bass although they sound really nice.

I’d like to build some Cubo 18’s, I was going to build 1 test cab out of mdf first that I’d like to put 1 of the fane 18xs drivers in to see how they sound a/b and together with my cabs. Is the fane 18xs a suitable driver for the cubo 18? If it all sounds good I’m thinking of running a pair alongside my original cabs

Then I’ll prob build 2 proper ones out of birch ply. I’m looking around for suitable drivers, people seem to favour the pd1850 but I’m worried they look quite heavy and expensive. 

What do you think to the RCF LF18N401? It looks like it could be ok + nice and light for gigging.

I’m pretty flexible as you can most things from blue Aran but it wants to be nice and loud, sound good not be too expensive and preferably fairly light.

Thanks for any advice you can give me in advance

Robin
Cubo15's Avatar
Cubo15 replied the topic: #24596 4 months 5 days 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 4 months 5 days 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 7 months 3 weeks ago
Great! Thank you as always!
songatron's Avatar
songatron replied the topic: #24501 7 months 3 weeks ago
AweDe
Cubo15's Avatar
Cubo15 replied the topic: #24499 7 months 3 weeks 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 7 months 3 weeks 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 8 months 1 day 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 8 months 2 days 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