Cubo 18

Hello I am new here and I am interested in rebuilding the Cub18. I have a question: Does it matter whether the magnet is in the chamber or facing outwards?
Many thanks Josef.

For best low end mount the magnet in the horn, for a warmer tone to the sound and a bit less low frequency, mount the magnet in the chamber.

Hello!

Just built this box and about to buy a speaker to it. would the B&C 18TBX100 be a good option?

Another question would RCF L18P400 be a better option than the B&C 18TBX100

Hi,

If you're going for a new driver, I'd consider the 18NW100. My personal preference is:

1. 18NW100
2. RCF L18P400
3. 18TBX100

The 18TBX100 is a good choice but I strife to get the lowest Qts, highest EBP driver possible.

Good morning
I have 4 Cubo 18 extended in South Florida. I no longer need them, going with self-amplified

Hi !
I could have RCF L18P540, seems like it is a suitable option, would you confirm me ?
Thanks !!!

Specifications
Nominal Basket Diameter
18"
Impedance
8 ohms
RMS Power Rating
350 Watts

Program Power 700 Watts
Peak Power 1500 Watts
Frequency Response
30Hz - 2.0kHz
Sensitivity (1W/1m)
99.5dB
Voice Coil Diameter
3" / 76mm
Max. crossover Frequency
1.0kHz
Voice Coil Material Copper
Diaphragm Materia Kevlar Paper Pulp
Surround Material Clth
Mounting Information
Overall Diameter
18.5" / 470mm
Bolt Circle Diameter
17.24" / 438mm
Baffle Cutout Diameter
16.38" / 416mm
No. Of Mounting Holes
8
Mounting Hole Diameter
0.315" / 8mm
Flange Thickess .51" / 16mm
Overall Depth
7.6" / 193mm
Net Weight
10.8 kg. / 23.76 lbs.
Thiele-Small Parameters
Resonant Frequency (fs)
34 Hz
Impedance (Re)
5.5 ohms
Coil Inductance (Le 1.23mH
Mechanical Q (Qms)
8.0
Total Q (Qts)
.34
Compliance Equivalent Vol. (Vas)
228 Liters/8.05cu. ft.
Voice Coil Overhang (Xmax)
4.5mm
Reference Efficiency 3.34%

The main problem is the low Xmax, meaning it's suitable for Cubo 18 Extended with a 300 - 600 W amplifier. Preferably with a high pass around 35 - 45 Hz.

Dear Mr. Cubo

Thank you so much for your contributions to the free speaker world. I have decided to build my first subwoofer (Cubo 18 Extended) and I got the 18NW100 following your recommendations. I only have basic knowledge in sound engineering but I have some expert friends in the field. However I have been confused regarding how to safely operate it. I might acquire the NX3000D amp since it already includes a DSP, I plan on using the limiter there but I was wondering if I really needed to add a High Pass Filter below the tuning frequency of the enclosure... Some sources say it's non-negotiable in order to prevent over-excursion and breaking it however others say that it's not really needed and it can actually cause all sorts of phase problems. The 18NW100 seems quite powerful and I would love to let it run free without constraints, what do you think? And if I really needed to add a hpf, what is the lowest setting I could get away with?

Thank you so so much in advance

Hi Charlie,

When you're not using a high pass filter and the music contains a signal below that high pass frequency, the amplifier and the loudspeaker will use part of their capacity to reproduce that signal. You're not hearing it, the amplifier is working harder and the loudspeaker is heating up quicker. Those are some good ingredients for a recipe to disaster.

At home I let my subwoofers run free most of the time, in a professional setting you're not making it run free, you're making it work harder. For the 18NW100 in Cubo 18 I would set a high pass at 30 - 35 Hz, 2nd order or more.

Best regards Cubo