First little setup

mini-mad wrote: thats a nice diddy stack there fella... keep the colour "turbo blue" adds at least 10db to the output of any speaker! but, as a bit of constructive criticism, get your sats up at head hight. buy tri-pods or something but getting them up high means you dont need to rag them trying to get them loud as the 1st few people in the crowd in front of them  will dampen the output of them. so next on your wish list: tri-pod stands!

they would kill your subs unless you limit the amp or  YOU are very careful.
the 2400mk-x is 2x650w@ 8ohms your drivers only handle 280w... just be reall careful and that amp weighs a fair amount (i have one as back up).

for the drivers you currently have a 400w @8ohms would be fine. or failing that if you budget is around the 250 marck you may find a lighter weight amp on the second hand market. even a berry euro 2500/2000 would be lighter. BUT if you are gonna upgrade those subs to better drivers at any point the 2400mk-x is perfectly fine. JUST WATCH YOU LEVELS!
 

thats a better amp for what you need... that one is 450 in 8ogm (nice little bit of head room!)

its 17.5kg, the 2400mk-x is 20kg (give or take) so i hope your young and have a good back!

i have a single tham12 with a PD12sb30 driver... and @400w it really does make some noise!
if you have two of these bass cabs anyway there is no harm in building another pair and running them off the 1400mk as 2x subs off each channel will NEED 560w, the amp will give you 700w. again a small 140w of head room but those amps come with a 3yr  warranty so you should be ok.
and four of those cabs stacked like this..



...in front of you with your sats midtops up nice and high the combined "mouths" of the MTH30 will be much louder then if you stuck them one each under the sats midtops. it will act like one giant bass box and means you wont have to rag the bass drivers to get the output you really need.

all bass wrote: sevenup wrote: I was told Xmax is between 6-7mm. My amplifier is 300W RMS, and I can give it full trottle.  The calculated x-max HC-HG /2 + HG/4 = 5mm the Box 12-280 8W

not the best.. but should give a fair amount of kick from a small cab. also as i pointed out a small stack of four with the mouths coupled will give you a little extra low end and ROUGHLY an extra 12db of output which means you should be able to get a hell of a lot of bass ooooooor... turn it down and have the same level you normally get and not over run the amp or the drivers.

in a block of four you should be able to dip down to 40hz ish with out to much effort. just dont be tempted to EQ the bass to much to reach down REALLY low or you WILL kill them drivers.

the point being coupling the horn mouths gives you a sort of a free boost in bass if you will.... and getting the midtops up nice and high at head level means you wont have to turn them up loud as they will be a ear level and wont be muffled by bodies as the would do just sitting on the bass cabs.

they are just small tips to prevent you trying to turn the system up louder and trying to kill your speakers when there is only 30 people in the room.

Great. Sounds like good plan for expanding the setup in the future with reusing equipment.