Cubo Kick

Two related questions:

If building the Cubo Kick 15 at 45mm wide does this reduce the VAS allowable for the driver?...or is VAS not a significant parameter in this design?

Should the decision to go with the Cubo Kick 12 vs the Cubo Kick 15 at 45cm width be based solely on the need for a higher crossover to the mid/top?

-Andy

Fs, Qts and Vas are the three primary parameters, so if anything you should be looking for the Qts x Vas product. Although I wouldn't worry too much as the port tuning also raises.

Cubo Kick 15 is deeper, meaning the horn is longer (and larger) thus it starts amplifying the output at a lower frequency. Typically the 15" will have more port output as well, again amplifying the lower kick.

P.S. Don't get your mm's and cm's mixed up

So for a given FS the lower Qts increases EBP (good) but to get a higher Qts VAS product you must have a big VAS... at what point does the VAS get impacted negatively buy the Cubo box size?....Or am I totally in left field?

-Andy

An increase in EBP is not necessarily good, it depends on your use, i.e. a single Cubo Kick or a stack (aim between 110 - 150 if unsure). A lower Qts x Vas product suggests better performance in a cabinet with a smaller chamber. A typical Cubo Kick driver will have a Qts x Vas product between 30 - 60.

What is a recommended XMAX for the Cubo Kick?

-Andy

For live sound with a full drum set bass and keys is there an advantage between the Cubo Kick 15 vs 18? 

For most venues space is limited so likely will often be a single Kick per side used with Cubo subs.

-Andy

Hi!

Dear Cubo I have question, - very important to me.
Thank you for your time if you would like to help me.
I plan to make a Cubo Kick 15 and want to use one of those speakers Beyma 15QLEX1600Fe or OBERTON 15NXB1200 (or maybe another from OBERTON?)

Which speaker do you think will be better? I want to widen the frequency response a bit up and down.


And the secon question:

Can I make two front skids (two pieces) slightly bent like a moon or should they be completely straight as in the design?
Hope you can understand what I mean.Thank you for answering.
Please advise if this is a good choice? Here are the parameters:

BEYMA 15QLEX1600Fe

Nominal diameter 380 mm 15 in
Rated impedance 8 Ω
Minimum impedance 6,3 Ω
Power capacity 1 1.600 WAES
Program power 2 3.200 W 
Sensitivity 96 dB 1W / 1m @ ZN
Frequency rangeRecom. enclosure
(Bass-reflex design) 35 - 1.000 Hz
Voice coil diameter 101,6 mm 4 in
Bl factor 35,6 N/A
Moving mass 0,254 kg
Voice coil length 32 mm
Air gap height 15 mm
Xdamage (peak to peak)  60 mm 
Resonant frequency, fs 33 Hz
D.C. Voice coil resistance,Re 5,3 Ω
Mechanical Quality Factor, Qms 6,3
Electrical Quality Factor, Qes 0,22
Total Quality Factor, Qts 0,21
Voice Coil Inductance, Le 3,7 mH
Equivalent Air Volume to Cms, 102 l 
VasMechanical Compliance, Cms 93 µm / N
Mechanical Resistance, Rms  8,3 kg / s
Efficiency, η0 1,6 %
Effective Surface Area, Sd 0,088 m2
Maximum Displacement, Xmax 13 mm
Displacement Volume, Vd 1144 cm3
Voice Coil Inductance, 3,7 mH

OBERTON 15NXB1200

Nominal Diameter 15"/388 inch/mm
Impedance 8 Ohm
Minimum Impedance 6.55 Ohm
Power Capacity AES ¹ 1200 W
Program Power ² 2400 W
Sensitivity 97 dB/W/m (50 -1000 Hz)
Frequency Range 38 - 1000 Hz
V. C. Diameter 100 mm
Voice Coil Material Copper
Voice Coil Former Glass fiber
Voice Coil Winding Depth 29 mm
Magnet Gap Depth 10 mm
Cone Material Paper with carbone fibers
Basket Die Cast Aluminium
Magnet Neodymium
Flux Density 1.27 T

Fs 38.49 Hz
Qms 8.255
Qes 0.337
Qts 0.324
Vas 111.94 litres
Mms 146.79 grams
Re 5.3 Ohms
Sd 829.6 cm2
Xmax* ±12 mm
Cms 0.117 mm/N
BL 23.62 T.m
Le at 1kHz  0.713 mH

Typical for a good 15" kick driver is an Xmax around 7 mm, at least 4 - 5 mm but as soon as Xmax gets beyond 9 mm it's a good indicator you're looking at the wrong driver.

Both the Beyma and the Oberton are high power sub bass drivers, great for Cubo 15 Extra Extended not optimal for Cubo Kick. I would look at 15" drivers with a 3" - 4" voice coil, Qts around 0.3 or lower and before mentioned Xmax figures, like the Oberton 15NXL700 or 15NMB500.

Can I make two front skids (two pieces) slightly bent like a moon or should they be completely straight as in the design?

I will have to see it to give a good answer to that.

Best regards Cubo

So if I understand correctly: The missing plans for the Cubo Kick 15 & 12 are the same as the ones for the Cubo Kick 18...? Just need to fill in the right sizes...?

The horn bracing is spaced out at 1/3 intervals, the port bracing at 1/4. For Cubo Kick 15 and 18 those intervals equate to those measurements.

Cubo