do you think i could adjust the inner depth to about 30cm and put thi 10" driver in:
I've builded a tapped horn with this speaker and want to know if the extra wood & weight is really worth it, because i'm planing to build serveral of them for some 5ghz connected 12v bicycle systems.
I suppose you mean reducing the inner width to 30 cm, although I would make it as small as possible, so perhaps 28 cm inner width. Also, with a single driver that wouldn't work out all that great, I would fit two 10" drivers (one behind the other) on the baffle. It should just fit, with about 1 cm between the drivers. Only one 10" simply doesn't have the Sd to make it work but two have.
Now, although I'm a big fan of 12V PA systems that drop down low, it isn't the most energy efficient. If output is more important or how long the battery lasts, two Cubo 12 (with reduced inner width) will have more output between 50 - 80 Hz. This is where the most energy in bass is located, it won't sound as low but add a lot of thump.
I made a 21" version of the Cubo Sub a few years back now which was fitted with an old-shool Precision Devices driver that was rated 750W rms (ET211S) but it never sounded that great due to the heavy cone I think.
Can anyone shed any light on the following driver and whether it would be suitable for the CUBO SUB - I cannot find any recommeded TS parameters for drivers on the page, neither can I find a post of anyone else making the 21" version to my knowledge.
Any insight would be greatly appreciated - the driver is the Beyma 21PW1400Fe with the following specs:
but it never sounded that great due to the heavy cone I think
It would be really nice if you new the T/S-parameters of the PD.
Now it's difficult to say whether you didn't like the driver, the cabinet or the incorporation into the rest of your system slash processing. If you know the T/S-parameters it's easy to compare them to the 21PW1400Fe and say if it's the same or completely different and if it attributed to your experience of the Cubo 21. To answer your question whether this is going to improve things for you without the T/S-parameters, we need to figure out what you didn't like about it exactly. What did (or didn't) you do to it, processing, amplifier power, what tops did you use (any delay on those), magnet inside the chamber, magnet inside the horn, etc. To me the 18LW1400 in Cubo Sub with the magnet inside the horn or inside the chamber sounded like two different cabinets, one for 'rumble' and the other one rather tight and loud.
It would also help if you have heard the PD's in another enclosure, anything that tells us if it's the driver, Cubo or system settings, or a combination of those.
Typically a 21" driver doesn't perform that much better than an 18" driver, in the same sized enclosure, it just has more potential. You need either a lot of power or quite a bit of EQ to get that potential (air displacement) to fruition. Someone in the Netherlands is building a custom version of it and probably going for the RCF LF21N551 or Lavoce SAN215.30, I assume with a small nuclear reactor to power the amplifiers because they can handle it and need that kind of power to really shine (beyond the scope of an 18" driver).