budget?

i'd start off with a focal amp..

FP 1.800..

and i'll say the audison thesis

A logical choice and a good choice Damo.

Or get another 21wx and use the tru tech A class-1

tru tech A class-1

Dont think its in production anymore though

Id suggest the Msk1500 Masterstroke or the QMOS11 310.2 amps by steg renowned for SQ and resonably priced (not so much on the masterstrkoke) I beleive Crankin Car Audio is a good sorce for this sort of thing there in sydney

You're all going overboard. Its only another sub.

Sure you can spend money for money's sake, but if its about the sound, dont make me give you the RC discussion 'small version'!!!

Quality of build, and warranty/after sales service are both more important. On a sub, $1k should be easily sufficient.

Ergo, that Focal is fine.

I would agree the focal 1.800 would be fine.
Have one myself good quality at a resonable price.
I think Marty from FHRX at on time was running that sub of the focal amp.

my post was smothered in sarcasm...we really cant advise this person without knowing a budget.
for all we know, they may have blown their budget on the sub alone, and now only have a very meager amount to spend on an amp
or they could also have squillions to spend, in which case why not spend it

but seriously, i do agree. buy from a quality brand, as much power as u can afford without being silly.
$1k should get you very good power from brands such as digital designs, focal, audison, alpine, jl audio, soundstream, etc

i would run an amp that has double the rated power wrms@4ohms compared to the sub............cors

thanks guys, the focal amp seems to be the most recommended, anyone think that having these amps assembled in Korea is of any consequence quality wise?

No

Korea is fine, the new Hertz HP range is Italian designed but assembled in Korea.
From what I here better Korea than China at the moment.

ive heard one off a tru tech 4100 running bridged and it was quite nice.....i was very impressed with the output too....would need two if it was me though

You will only need around 400W RMS, so you can get away with a A/B Class amplifier on it
without worries of effeciency and your alternator dying.

I had 2 of these subs, the first one i had I overdrove it and hit the voice coil on the backplate,
which seems almost impossible when fiddling with the sub mechanically but it supposedly did happen. It's not a SPL Sub, so it won't take backplate hits in it's stride!

I was running off the back of my Soundstream Van Gogh 500.4, so it had 500W RMS into 4 ohm.
The 500W rating these subs have is "MAXIMUM" not RMS. they are 250W RMS.

so you do need to be careful with the sub if you run a high power amplifier.
they are fairly sensitive to the quality of the amp, and it's noticeable if the amp isn't up to the job.

the Focal FP800.1 should be perfect, 400W @ 4 Ohm is plenty for the 21WX.

They are a very impressive subwoofer, but they are not for doof doof heads, they will play anything you throw at them without breaking a sweat at moderate high volumes, They will play right up till they bottom out without a Hint of distortion (unless the amp is distorting) but if you want High volume then you best head for the 33KX, its sound and function is extremely similar, but with 250% more output. The biggest downside of the 33KX is the 50 litre box. (but then you need 30 litres for the 21WX.. so it's not that bigger difference)

regards
Juls

Good advice there Juls, but I'm honestly interested in the above statement. What part of the 'quality' of an amp is a) measurable, and b)descernable by a subwoofer?? And is that due to the quality of the driver (what measurable part), or the sensitivity (in which case, any pro woofer would show it too)?