@audiokinesis 1+

If you want higher performance you will need a two way crossover such as a MiniDSP or a preamp with digital bass management. I do not like Crown amps. I have had them twice and both times they were unsatisfactory. I use QSC PL380s which are killer subwoofer amps, but on the pricey side. The GX5 will be fine and it has a built in subwoofer low pass filter. DO NOT use the RMX series amps. They have a habit of self destructing. I personally destroyed 3 RMX 5050s, fortunately under warranty. Finally, QSC insisted I switch to  PL380s, a more expensive amp by $1000 each and they did not charge me the difference! They are the best subwoofer amps I have ever used. QSC gets an A+ for service.

@mijostyn , thanks for the QSC suggestion. 

I should have mentioned that the Dayton SA-1000 has a fixed 80 Hz second-order line level highpass filter to roll off the bottom end going to the amp for the main speakers.  No DSP in the Dayton; it's all analogue. 

Reliability has been very high in my experience; aside from a brief string of defective units that were either DOA or died within the first couple of weeks, I've only had ONE unit (out of about 200) fail in the field.  It failed about 4 years and 10 months into the 5 year warranty, and Parts Express replaced it under warranty. 

Duke

@audiokinesis I use Dayton Reference subwoofer drivers and I get them from Parts Express. I have not seen anything that is functionally superior at any price. They make sub drivers suitable for any enclosure situation. 

I do not like putting electronics inside subwoofers. It is not a great environment for electronics. Forgetting about the pounding they take, heat is a problem in small sealed enclosures. Pushed loud for extended periods sub drivers get hot producing an oven environment. How hot I can not say, but I dissected an old driver that I used for 20 years and the voice coil was black!   

Subwoofer bass myths, see here!

Mike

@mijostyn , I agree with you about the heat issue.  Except for the very first generation of my subwoofer system, dating back to 2006, I haven't been putting amps inside of subwoofers.  My observation (based largely on conversations with customers) is that high-power compact equalized sealed-box subs tend to have fairly high failure rates for their amplifiers and their woofers, and I think it goes back to the "oven environment" you described.

One of the reasons I use vented enclosures (tuned such that their response is the approximate inverse of typical room gain from boundary reinforcement) has to do with thermal power handling.  A comparable sealed-box sub will theoretically need roughly three or four times as much power in the region of the port tuning frequency in order to have the same frequency response.  Also, a port allows an exchange of air with the outside world, so you don't get that "oven environment" that you do with a high power sealed box sub.  In other words, imo there are arguably worthwhile thermal benefits from making a vented box approximate the frequency response of a very low-Q sealed box down to the port tuning frequency.

In my opinion.

Duke