I have four Cobo 18 extended that were loaded with FaneXB's 1000w 8ohm they were ok but the bass was not quite deep enough so,
I have now upgraded to RCF LFX451- 18" 1800w 8ohm. The problem is the bolt pattern and the cut out hole are very different therefore; I may have to use clamps instead of m6 bolts and T-Nuts not having enough space to get a router and a drill in the cab to work on the baffle. Can I place another baffle on top of the existing one and what difference will it make to the performance and sound quality.
Mounting information: RCF LFX451
Overall Diameter: 465 mm / 18.3 inch
Bolt Circle Diameter: 442-447 mm / 17.4-17.6 inch
Bolt Hole Diameter: 6.5 mm / 0.25 inch
Front Mount Baffle Cut-out: 424 mm / 16.7 inch
Rear Mount Baffle Cut-out: 424 mm / 16.7 inch
Depth: 194 mm / 7.63 inch
MOUNTING Fane XB
Overall Diameter 19.1" / 485 mm
Width Across Flats 18" / 457 mm
Flange Height 0.465" / 11.8 mm
Baffle Hole Diameter F/M 16.52" / 420 mm
Baffle Hole Diameter R/M 16.33" / 414 mm
Fixing Holes 8x 0.275" diam on 18.425" PCD
8x 0.275" diam on 17.25" PCD
8x 7 mm diam on 468 PCD
8x 7 diam on 438.15 PCD
Depth 8.07" / 205 mm
Thanks in advance and I look forward to hearing from you,
Did you try the Fane with the magnet visible or magnet inside the chamber? That orientation has some influence on how deep the driver goes in Cubo 18 Extended, although most of it is due to Cubo 18 itself and not the driver. The RCF LFX451 is a good sub driver so it might change how deep it goes a bit but not by much. Because the RCF has good Xmax you can use o bit of EQ to get most out of
it but if you need much deeper bass Cubo Sub might be a better option for it.
I usually make a 18 - 30 millimeter ring on the baffle that has two sets of bolt patterns in it. It has 8 t-nuts for the new driver and spaced in the middle between those holes, 8 clean holes for the old driver. The ring is then mounted onto the baffle using hex bolt countersunk heads, so the ring surface is flush. The new driver can then be mounted with short bolts via the t-nuts. I like to countersink the t-nuts a bit, so that the entire bolt threat is used before exerting maximum (bolt clamp) force on the threat. The bolts are 17 - 29 mm plus whatever extra length is need for the driver, so they don't touch the baffle of the Cubo, this means they might need to be cut to length.
I've seen those clamps used before on heavy drivers, although I've never used them, they seem capable. So if implemented the right way that could be an relatively easy fix.
Please excuse me for the delay in replying to your response and thank you so, so much with all your help regarding the baffles and bolt holes.
In the end I made a double baffle and only used two of the four Cobo 18's with two specially adapted smaller cubo 15" cabs in a medium sized hall (they ROCKED and Tore the place down OMG happy days)
A friend of mine has finally completed building his Cubo 18's (hearing mine recently has given him a push) he would now like to extend them like mine. Can he place the 18cm extension board in the cab now the cab has been built or will he have to make new cabs.
Like you suggested in the last thread "Because the RCF RCF LFX451 has good Xmax you can use o bit of EQ to get most out of it but if you need much deeper bass Cubo Sub might be a better option for it" therefore I am now thinking about building some Cubo Subs to add to the arsenal but; I do not have a workshop, the weather is not so wonderful to build outside now and I am running out of time so, I'm considering buying some Mini Scoops, do you think there will be any compatibility issues?
After building 3 Cubo Sub's, which I love, I want to build a couple of Cubo 18's for the "portability" advantages. I scrubbed the thread but could not find recommendations of B&C drivers. Cubo, what would you recommend from the currently available 18" B&C drivers (
) ? Thanks.
Personally I favor lower Qes drivers in Cubo 18 Extended, so the 18PZB100 (ferrite, decent power handling), the 18NW100 (neo, high power handling) or the 18DS115 (cost no object, very high power handling). Considering you already have Cubo Subs, the 18DS115 might be a bit much.