Cubo Sub

Thanks for the reply Cubo!

I'll give them a go in a regular Cubo18 (extended) first then, I'll be building one over the course of the next couple of days anyway for some Beyma 18p1000's I have lying about.

Hi Cubo,
Seeing that you recommended to me to build the Cubo sub for Faital Pro 18XL1600, just a question.
Would it make a difference in the sub if one has to add 50mm panel's on each corner of the horn path.
Reason I ask is that I built a pair of THAM12's and did that as per the revised plan's. It was suggested that the flow in the horn path becomes much smoother.
What is your opinion on this?

Just curious Johan what makes you like higher ebp drivers more in these designs? it was one of the things i considered in picking the 9601 over the 9001, and would you consider the 9601 a high epb driver with a value of 119?

After doing some more research i learned that the cubo sub is around 300 litres and the recommended volume for the 21nlw9601 120 - 250 ltres, made me worried about my choice maybe being ineffective

@ Housexy: IIRC about 10 years ago, Thomas Danley (then at Servo) made a completely smooth bass horn and a regularly build bass horn. Their conclusion was it didn't have a noticeable effect for bass horns (<120 Hz). In fact the effective volume of the horn became less, thus performance was lowered as well.

If I would build a bend or folded horn that would need to reach up to, say 450 Hz or higher, I would definitely include it. For <200 - 300 Hz, personally I wouldn't bother.

@Nocturnal92: Stolen from wikipedia: EBP - The efficiency bandwidth product, a rough indicator measure. A common rule of thumb indicates that for EBP>100, a driver is perhaps best used in a vented enclosure, while EBP<50 indicates a sealed enclosure. For 50<EBP<100, either enclosure may be used effectively.

For EBP>>100 drivers get more horn orientated. EBP above 200 indicates mid to high frequency range. Personally I would keep EBP preferably between 90 - 180 for Cubo 18 but for Cubo Sub 75 might still do.

The recommended volume is only applicable to reflex enclosures, for horns it's the bigger the better.

Best regards

Cubo

hi cubo, i wrote you an e-mail some days ago, but i didnt get any awnser, i would like to build a rig with 2 cubo sub 218 and 2 cubo kick 215, can build the cabinets like this or it will cause problems at the horn paths?

Yes you did, making you one of the 11 people to ask me a Cubo related question in the past 5 day's. There's also this academic figure asking me to convert a one-pot-Grignard-synthesis in a way to make asymmetric bifenyl's (I'll be doing that tomorrow). I find it harder and harder to respond within one week of time

Yes you could, it's the preferred way of making a Cubo 218 (which I assume from looking at your model), which is not the same as Cubo Sub 218 by the way. Couldn't find much about your tops, a link would be helpful.
Cubo Kick will actually perform better when the mouth's of multiples are combined.

Best regards

Cubo

Hi Cubo, I hope you are well! I'm drawing nearer to actually building and replacing my Cubo 18's with Cubo Sub's and was wondering (considering they are the same price) whether the RCF LF18x401 as previously planned, or Void V-1000 drivers would be 'better'? I want to get as low and as loud as possible, with low being the primary goal, I also like the idea of having Void drivers (it would give extra kudos to my rig in the circles I move in!), but if there is anything else in the £250 driver range I should consider then I am also open to suggestions!
Many thanks again for your time.
Edd

Hi cubo, I was thinking about building 4 cubo subs with beyma 18ws1600nd neo's in them to add some extra bottom end to our stack.
How do you think they'll do in these? Would you favor them over RCF LF18x401's (I can get them for the same price of 300 euro's)?

Thanks!

Specs:
www.beyma.com/products/lowmidfrequency/118SW16ND8

TECHNICAL SPECIFICATIONS

Nominal diameter 460 mm 18 in
Nominal impedance 8 Ohm
Minimum impedance 6.1 ohm
Power capacity 1600 W AES
Program power 3200 W
Sensitivity 97 dB 1 W @ 1m
Frequency range 25-1800 Hz
Maximum recom. frequency 200 Hz
Recommended enclosure volume 80 / 200 l 2.8 / 7 ft³
Voice coil diameter 120 mm 5 in
BL factor 29 N/A
Moving mass 0.260 kg
Winding length 25 mm
Air gap height 14 mm
Xdamage pp 60 mm

Fs 32 Hz
Re 5.5 ohm
Qms 11.74
Qes 0.34
Qts 0.33
Vas 205.7 l
Cms 94.3 µm / N
Rms 4.46 kg / s
Efficiency % 1.93
Sd 0.1255 m²
Xmax 10 mm
Vd 1164 cm³
Le @1 kHz 3.1 mH

@Tetris: Whilst I'm convinced the V18-1000 is a great bass driver I'm not sure how good a sub driver it is. It will work without a doubt in both Cubo Sub and Cubo 18 but if I would compare drivers, and decide how suitable they're for use in Cubo Sub, there's 3 parameters I would definitely like to know. The exact thing I always wondered about with the V18-1000, is what it's gap depth, VC winding height and Xmech are.

With the LF18X401 that's all crystal clear and it's obviously a great sub driver. With the V18-1000 that's a guess, it might, it might not. You could always cover the grill with acoustic transparent foam and just claim it's the V18-1000

Looking at several other parameters between both drivers I would think the RCF will perform the best (be the loudest) below 50 Hz, with the V18-1000 being the loudest above 50 Hz.

@Tempest: Nah, I would still go for the LF18X401, It is as if, with the RCF they took a bit of extra flux and gave it more Xmax, that's what you use for more mechanical power handling (aka sub frequencies). With the Beyma they took a bit of extra flux and gave it a bigger voice coil, that's what you use for more electrical/ thermal power handling (aka high power bass). That aside they're both very decent all round sub/ bass drivers. It's just that that bit extra went in different directions.

Best regards

Cubo

Thanks for the info cubo, you rock!