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.