Repair JL Audio F112 or buy new Rhythmic, SVS, or ??

That is excellent news! Writing letters can work small miracles. Good job for being calm and letting them make the right decision.

It seems I have found the best answer. I wrote to JL Audio, calmly explaining the issue. Given the history of repairs to my subs, they offered to fix this one under (the long expired) warranty. A generous offer and one I expect to accept.

I should mention, that in my rooms I can get down to 16Hz with the ports sealed with a single Hsu.

I forget to mention that there's an excellent source of information here:

https://data-bass.com/

Guys, that first youtube link shows port chuffing on a Hsu subwoofer with those triangle ports.  Granted, this is an extreme example with very low bass that you would not normally get (probably in the 20-35 hz range).  Nothing against Hsu in general, but it does show what happens when air movement becomes too much for a certain port design.

It's a shame that JL Audio quality is not better. Tough call on repairing but if you're stereo subbing your mains, the repair may make the most sense as two F-112s are nothing to sniff at performance-wise.
I just acquired an SB-3000 (sealed) for my main audio only system and it is competing very favorably against an old $3200 R.E.L. Britannia B1 (which is ported).  It's blended with rather quick Raidho D2s and is pulling off the job very well. The SB-3000 is easily in-room flat to 31hz, the B1 will hit 25 with its port but I have no music that low. (Both are audibly invisible, thankfully crossed low.) And, I tried an SB-2000 (one of two for home theater, also just received) with the D2s and was really surprised.

Hsu Research, imo, has been manufacturing high value subwoofers for a long, long time. They seem to be one of the originators of that lower end market. Now we have other good brands like SVS, Rhythmic, and others.
Good luck figuring it out. A local repair might be most cost effective and preserve a nice system.

Thanks again, guys, for the comments. A lot to mull over.

The Hsu subs come with port foam to seal them, and I've never heard any chuffing at all. 

Chuffing happens when air velocity is too high, which is reduced with bigger ports.  The ports on the HSU 15" subs are gigantic.

Having said this, in a modest living room, sealing them often results in smoother low end (16-32 Hz) response.

An example of what this port chuffing sounds like is here:

https://www.youtube.com/watch?v=mLVlAm_ZpeA


Here's the same demo sound with a Rythmik sub.  It's using a Rythmik LV12R, which is a rear ported sub, so the audio may not be picking up any chuffing that the sub may be producing, but the video shows what this should sound like without the port chuffing resonance.

https://www.youtube.com/watch?v=c4mc4CxPiak

thanks.

I did a bunch of research for a friend on a new sub.  JL Audio makes really good subs (even though it appears that electronics may not be spec'd great).  I think the main reason to switch away from JLAudio is if you want to get a vented sub.  There's a difference in sonic signature between sealed and vented.  Sealed subs are extremely clean sounding, but for some personal tastes, they are too clean and can come across almost artificial (hearing bass tones that sound almost like an artificial sine wave instead of a natural resonating instrument).  Sealed subs also require more power and an EQ adjustment to boost lower frequencies because the sealed box/driver is not able to do the lower frequencies without help.

Vented subs are more power efficient for the lower frequencies.  They also have a meatier sound to the bass tones.  You may or may not like/want this type of sound (I would prefer vented/ported subs myself).  There's also industry controversy that state vented/ported subs create more distortion (which could be true and is a characteristic of the meatier sound).

SVS vented subs have a particular sonic signature that is popular among the more "consumer electronics" BestBuy type of home theater crowd.  It's hard to explain, but it's a type of boomy or a type of resonance that kind of takes over the whole sound.  Some people like it, but I personally don't.

Another thing to watch out for is port resonance on certain subs.  The Hsu subs with those triangle ports create a lot of "chuffing" port wind resonance.  Some other subs, such as Klipch, also have this.

The Rythmik subs are probably about the best audiophile type vented subs I have found.  That's what I would recommend if you wanted to go vented.

I'll add Hsu to my list. Thanks!

I just saw that you have an Anthem to do ARC for you.

In that case, I strongly suggest a Hsu. :) Absolute beast-mode subs.


Best,

Erik

Erik --

It appears that JL Audio under-spec’ed some electrolytics on their plate amp; when they repair, they use higher-spec ones.

My subs are v.1 and have only the one-band ARO (EQ) -- which I don’t use, as my Anthem STR Preamp does more.

A repair would be more cost-effective, giving me a great sub for $600, and one that matches my other, recently repaired, sub. But buying something new would have amusement value, sorely needed these days. People seem to like the Rythmiks a lot. Any experience with them?

I wish I didn't read so many Agoners having trouble with their JL subs.

The biggest reason IMHO to spend the big bucks on JL Audio is for their built in auto configuration software.

If you go with a brand that doesn't have this, be sure you can get the same results.

Thanks, guys, for the advice. @golfnutz - I considered doing it myself the last time. Decided against it because of lack of space, poor eyesight, and mediocre soldering skills. However, I may reconsider this time.

Golfnutz' link photos are interesting. 
The Velodyne subs I've owned had increasing amounts of a clear caulk like material generously applied to the surface mounted components.

When I had an early F113 in the house it was an impressive subwoofer but the auto only A.R.O. and lack of remote control was a drawback coming from Velodyne.

I'm totally hooked on my Plus' remote control and preset equalizations so I'd lean towards the DSP SVS pick. In home trial period and a warranty?
Good luck with it.

Have you checked this thread out?
Would be cheaper if you could do the repair or have someone else locally do it for you (assuming your issue is the same as the thread I've linked).
https://www.audioaficionado.org/showthread.php?t=43298