Originally Posted by duc135
First off, you would be better served by posting your sub question over on the sub forums. Lots of very knowledgeably people over there who will be able to help you.
Second, keep in mind that it should be considered a bass system and not just a subwoofer. The subwoofer reproduces the sound, but there is a lot more to it than just a subwoofer producing the low frequencies.
Third, whoever told you that you won't be able to adjust to a sealed sub because you're coming from a sub with passive radiators is mistaken. All things being the same, properly designed subs will sound the same no matter the enclosure design. Take the same driver with the same amp and put them in a properly designed
sealed, vented, passive radiator or horn loaded enclosure and it will all sound the same when level matched within it's design specs. The differences will be the trade-offs you are willing to live with. Sealed enclosures are small and offer the most extension down low, but at a cost of output. You will need lots of power and multiple units to equal the output of the other designs. The bigger the enclosure, the less power you will need to produce higher output generally speaking. The problem with non sealed designs is that the box is tuned for a certain frequency where it is most efficient. Anything below that tuning frequency and driver excursion is uncontrolled and will require some type of HPF to prevent damage to the driver. Because of a need for a HPF, output below that frequency starts to drop like a rock.
Fourth , boomy or tight fast bass has nothing to do with enclosure type or driver size and everything to do with proper design and room modes. A poorly designed sealed 10" sub can sound as boomy and muddy as a ported 24" sub. Proper sub placement is key and the first thing that needs to be done in attempts to get good clean bass. Second would be to get multiple subs if possible. Doesn't matter what enclosure design you decide on, multiple subs will help alleviate room modes that will cause peaks and dips in frequency response. Third is acoustic treatments like bass traps. To fully understand what's going on in your room you should get a mic, download REW and learn how to take measurements. This will go a long way towards getting good smooth frequency response.
Lastly, I don't see where you would need a sealed sub with tight bass to properly integrate with your F52s. The F52s themselves are ported designs. If you feel that the F52s have tight bass then that should tell you that ported does not equate to boomy or muddy bass. I know you were not the one who stated this, but I know someone had mentioned it. Whether or not a sub can keep up with your F52s is more a matter of your personal taste and room size.
All that being said, I can't really make any recommendations other than to look into the usual suspects: JTR, Seaton, Rythmik, Funky Waves, SVS, HSU, etc. While the JL Audio subs are nice, I think all these non ID subs are way too much money for the performance. I'm more of a DIY sub person myself. For example, for the price of a single JL Fathom F112 I was able to build two 18" LMS Ultra 5400s in sealed enclosures each getting 7KW (peak) and a MiniDSP to EQ them. There is no way a single JL Fathom F112 could touch the output of a single LMS let alone two of them. I could have built even more subs or reduced the cost by at least half if I went with cheaper drivers, but decided the LMS fit my needs the best. Clean, powerful bass can be had for cheap if you are willing to put some elbow grease into it. If this piques your interest then head over to the DIY forums. It's amazing the things the guys over there can do.
I apologize if you knew all this already, but I just thought I'd point that out in case anyone else was following your subwoofer journey and gets the wrong impressions.