JBL L112 Deep Bass

I have a set of L112s, which I love, except for what I think is a bit too boomy lower mid-bass, and lack of deep bass. Has anyone combined these babies with a good quality sub crossed at about 100hz? I am not looking for a boom box, but well defined lower frequencies, and taming the lower mid bass a bit. I use the GFP 565 Preamp in by pass mode (no tone controls).

Rest of system, for info:

Adcom GFA 555MkII Amp
Adcom GFP565 Preamp
Adcom GTP500II Tuner/Preamp used as a Tuner.
Marantz CD5001 CD Player
Dual 1249 TT
Audioquest Groove Dancer and Stanton 681EEE Mk III cartridges

How do you have the L112s positioned?

Never owned a sub so I can't help with that, but there's a lot of difference in bass performance and how the L112s are placed with respect to barrier reinforcement related to side walls and floor.

Yes, you'll get more from placement adjustments, stands, etc. I wouldn't put them on a 100Hz XO either. Maybe 40-60.

posted a few years ago (?):
L112's, 80Hz 18dB/oct active crossover,
SUB1500-based subwoofers (one per side).
Large room.
Best I've heard from the L112's in a room that size.

Right now I have the L112's on ~20" stands in a smaller room
(the SUB1500's would be overkill).

A good audio quality sub really helps out. The technology has moved very quickly and what is out now, compared to thirty years ago is very, very nice. I'm running an older Carver sub with the L5's with very good results. My other system has a pair of Velodyne HGS-12 subs supporting a pair of 4315's and you can't tell where one leaves off and the other picks up, it's that good. Totally seamless to the ear.

You're going to get what you pay for, so do the research. If you're into DIY, Parts Express sells some pretty intense subwoofer kits for reasonable dough.

Also true that a sub, no matter how good is it, does not fix issues created by speaker placement and setup. For music, the L112 can be set up to be near perfect but does still lack in the under-40Hz range. It does tend to the thumping sound especially if not well placed. I like them at lower volume but think they need a LOT of space around them for the best sound especially if pushed.

IOW, if there are issues created by placement and lack of EQ, adding a sub will not remove them. I think I'd round up some good sweep tones and sine wave tones and isolate exactly where the peaks and valleys are, then proceed with placement adjustments before looking at a sub. That's not to say that a sub won't be a nice addition. But doing the above first will give you the info you need to set up a sub too.