Cubo 15

n0 is the driver efficiency (in %), some manufacturers give it in the PDF. It's also used to calculate the drivers sensitivity (although most manufacturers use sensitivity figures from a rampant marketing department). n0 (a.k.a. Eta Zero a.k.a Reference Efficiency) is calculated from the Fs, Qes and Vas as follows:

Fs^3 x Vas / Qes x 9.6E--8

Half space sensitivity: 112 + 10 x log (n0/100)

So for the L15P540

50^3 x 100 / 0.41 x 9.6E-8 = 2.93%

112 + 10 x log (0.0293) = 96.7 dB/W/m

As most 4" VC drivers have a lower Fs,you would have to raise Vas and lower Qes a bit to compensate.

Best regards Cubo

Cubo15 wrote: n0 is the driver efficiency (in %), some manufacturers give it in the PDF. It's also used to calculate the drivers sensitivity (although most manufacturers use sensitivity figures from a rampant marketing department). n0 (a.k.a. Eta Zero a.k.a Reference Efficiency) is calculated from the Fs, Qes and Vas as follows:

Fs^3 x Vas / Qes x 9.6E--8

Half space sensitivity: 112 + 10 x log (n0/100)

So for the L15P540

50^3 x 100 / 0.41 x 9.6E-8 = 2.93%

112 + 10 x log (0.0293) = 96.7 dB/W/m

As most 4" VC drivers have a lower Fs,you would have to raise Vas and lower Qes a bit to compensate.

Best regards Cubo

Thanks!  I'll keep my eyes on similar drivers having 4" coil etc..  

L15P540 is still good driver anyway, nothing wrong with that.. tight and punchy. Sometimes these drivers are making loud bangs (input power around 1kW peak) while cone moving around 15-20mm only..sounds like coil hitting back plate. However, specs says Xdamage being as high as 36mm!  
No matter if rising HP up to 45-50Hz, still bottoming or something similar if pushed up to 1kW. 

hello everyone, I would have a question about the Cube extended.It would be my intention to use a CIARE NDC 15-4S NEO, in an extended cube box. these are the parameters: Thiele-Small
Qms 2,59
Qes 0,28
Qts 0,25
Fs 31,20 Hz
Re 5,96 Ohm
Mms 160,97 g
Cms 0,16 mm / N
Bl 26,09 T * m
Sd 830,00 cm2
Vas 156,24 litri
u 1,66%
XMax 11,5 mm
Le 1,07 mH
Rms 12,18 Kg / s
Larghezza di banda di efficienza 112,92


could it be a good choice?I have a couple of them at home and I would like to use them to build a couple of compact divers for a small PA. what could be about the pressure in spl max achievable?

Hi,

You can use the Ciare NDC 15-4S in Cubo 15 Extra Extended (send me an e-mail at questionsaboutcubo at gmail dot com) or in Cubo Sub. In Cubo 15 it will have about 100 dB/W/m sensitivity, so about 130 dB continuously (not factoring power compression). In Cubo Sub it's about 3 - 5 dB lower, so 125 - 127 dB continuously but what you miss in SPL you'll get back in air movement if playing 30 - 40 Hz.

Best regards Cubo.

I'm look the plans for the cubo 15 and cubo 12, then, I decide to buid cubo 15 because is more suitable for my needs.

What I need: A pair of small bass cabinets to play live with my small band (4 components: drums, keyboards, acoustic guitar, vocals. The bass line is played from the keyboard). Other important point is there this bass cabinets need to be easy to be moved from one place to another. For me the cubo desing is the best compromise between space and SPL.

The way whic I will use 2 cubos is runing it by a DBX drive rack PA2, for use the crossovers, compression and limiter, and power it by an NUKE 3000 amp (~2000 W RMS @ 4 ohms bridged).

The drivers which are possible at Brazil are:

Snake Pro ESX155 - Cost 609 BRL
Cms - NA mm/N
FS 35 Hz
Qms 7,123
Qes -0.362
Qts - 0.345
Le - 0,92 mH
Vas - 193 L
Power (RMS) - 600 Watt
Re - - Ω
Coil - 100 mm
Impedance (Ohm) - 8 ohm
Mms - 107g
Sens. - 97dB
Xmax - 9,5mm
EBP 101
QtsxVas 66,6
Eff 2,6%

RCF 15P540 - Cost 839 BRL
Cms - NA mm/N
FS 50 Hz
Qms 9,7
Qes -0,41
Qts - 0,39
Le - 1,5 mH
Vas - 100 L
Power (RMS) - 500 Watt
Re 5,6 Ω
Coil - 76 mm
Impedance (Ohm) - 8 ohm
Mms - 106g
Sens. - 98 dB
Xmax - 7 mm
EBP 128
QtsxVas 39
Eff 2,94%

The tops which I use are 2 full range 200 W RMS, 12 pol woofer and driver, crossed, and use it in stereo mode. I will cross the cubos, to run in mono, at HP @ 40 Hz and LPF @ 100 ~110Hz. The system is for live sound in open and close spaces, but not at so high loud levels.

The questions:

1. What are the cost benifit choice between the 2 drivers?

2. What is the correct choice: cubo 15 standart or extended?

Thanks in advance for the support and attention. All information in this forum is very hellpfull. I'm read the full topic for cubo 12 and now i'm reading the topic for cubo 15 (at page 44).

On paper the Snake Pro ESX155 looks better than the RCF 15P540, however the Xmax looks questionable to me, efficiency is also a bit lower at 2.2%. If the specs are indeed true, the ESX155 would be the better choice. However, considering the tops you're using both will work and I expect you'll have output to spare (on the Cubo 15's).

I've updated the plans page, to include an easy calculation to what version suits what driver best:

Qts x Vas > 120, Cubo Standard
Qts x Vas = 100 - 120, Cubo Extended or Standard
Qts x Vas < 100, Cubo Extended
Qts x Vas < 50; Cubo 15 Extra Extended

Best regards Cubo

Ok I want more kick for my setup as showen before. What should I build? 2 cubo 12 kick? Any suggestions? And what driver? Cubo 15 would be to much for single Cubo 15 extended? 

It really depends on your needs, one Cubo Kick 15 on one Cubo 15 is usable for Live music where there isn't much sub content to cover. For DJ's two Cubo 15 for every Cubo Kick 15 often balances out. Cubo Kick 12 by the way reaches the same sensitivity eventually, it just steps in from a higher frequency, missing the lowest bit of the kick, in exchange it reaches higher.

Best regards Cubo

Actually I use them mostly home and for some raggae/dub parties and pure techno. But if I listen on psy.. I want more 909 kicksound. 

A 909 kicksound peaks at 63 Hz and is -10 dB at 180 Hz and 30 Hz, so Cubo Kick 15 looks to be the best choice here.

Best regards Cubo