JBL L112s Mixed emotions or bad woofers?

[WifesPissed]

So I bought a pair of L112s a while ago from a garage sale, not expecting much. Repaired the surrounds and fired them up and was blown away by the "reality" of the speakers.

I had recently just finished restoring a pair of Infinity RS-6000s which were my current favorites.

After considerable A/B (limited space), I chose the JBLs and sold my 6000s.

Well after six months, I have become a bit disenchanted with them. I have read here that the bass on the L112s is powerful and I have a nice Denon receiver that pumps out a decent 140W x 2 RMS, clean with good reserves.

The mids and uppers are what locked the JBLs for me against the Infinity. But the bass was not comparable. The dual acoustically suspended 10" drivers and the 2.5 ohm impedance (which drove the Denon to 350W x 2) if the Infinitys was in a different league. The Infinity bass was deep, fast, and tight. Always there, hitting you in the gut then disappearing. Going low (37 Hz) effortlessly.

The L112s is the opposite, "there" but not always powerful. Loose and sometimes muddy.

I have checked polarity and the drivers seem to be in fine shape.

One note, when I first rebuilt the speakers, one of the woofers had been replaced and the internal woofer wires were rolled. So I swapped them back and checked overall polarity with a battery. The speaker pair matched.

So, after my diatribe, I am curious to get everyone's opinion on these L112s as far as bass.

I have not been able to get the bass anywhere near what I would like and am beginning to despair. An amazing speaker, tainted with a poor low end?

Maybe I need a full 300W?

[BMWCCA]

What surrounds did you use and where are the speakers placed? Mine work fine with a Crown D150 (80 watts) but (like most speakers) they're susceptible to placement parameters such as distance to floor, walls, and corners.

[brutal]

I've always been impressed by the bass of both of my sets of L112's. The originals I had reconed a few years back do hit a little harder than the refoams I put together a few months back.

I currently push one set with a pair of Yamaha M-80's bridged (est. 400WPC+), and the other with a pair of Rotel RB-980BX bridged (360WPC) but ran my L112's for 20 years with a Yamaha M4 amp (120WPC).

Read my 250Ti post for more info RE: L112 bass. http://audioheritage.org/vbulletin/s...ad.php?t=18705

Have you gone through the x-over schematic for the L112 and double checked everything? Are you running them in an HT setup with other new gen speakers? You may have a phasing issue.

[WifesPissed]

I used quality generic, not JBL surrounds. The vendor was familiar with the L112s and sold me the surrounds.

They are place on a carpeted floor about 4 ft apart. Raising them 6" did not do much.

They are not played with any other speakers.

I have not checked any of the components.

So should I suppose, according to the experienced ears here, the JBL woofers should be very satisfactory if performing and setup correctly? I know acoustically suspended drivers tend to be tighter maybe the comparison and expectation is not a fair one?

[brutal]

You could try either a higher powered amp or maybe experiment with some port plugs.

Do you know the damping factor of that amp? It's my understanding the L112's do need a lot of control (damping) to sound right. I guess my Yami's (and the Rotels to some extent) have always had sufficient damping characteristics.

I would still get a hold of a schematic and get inside to check everything out. You may have some grubby internal wiring also. The set I just restored had some heavy oxidation on the backside of the crappy twist style binding post wiring (push on). I always replace them with Dayton 5-way gold posts soldered to the x-over inputs. Also, are they truly 128H drivers? Got any pics?

Cheers!

[WifesPissed]

Thanks brutal. They are 128H drivers for sure. I don't get any noise adjusting the high and mid trim pots on face. The Denon AVR-3600 seemed to control the Infinity drivers very well but then again, they were sealed boxes.

I will seek to check the electronics inside. I'll search for some threads here on that.

[grumpy]

by all means... check the wiring:

http://manuals.harman.com/JBL/HOM/Te.../L112%20ts.pdf

and enjoy some light reading:

http://audioheritage.org/vbulletin/s...ead.php?t=4554

It may very well be that you just like the Infinity bass sound better.

[BMWCCA]

It may very well be that you just like the Infinity bass sound better.

Not likely, since WP made the decision on which speakers to keep with both operating in the same environment. Now all he has is the memory of the Infinities. Cognitive dissonance?

[toddalin]

I've always thought that my L112's sounded a little "dull" and while they are fine, they certainly don't have the impact of my large format monitors. Still, at $50/pr (and the lady threw in a beveled glass Parson's table top for nada), they are hard to beat.

I took the woofers out the other day for refoam and will let OCS handle it. (Not the cause as they always seemed a little dull to me.) I'll be sure that the paperwork notes to put the foams on the backs!

[grumpy]

Cognitive dissonance?

Sure, that works.

I like mine just fine for what they do. Up off the floor and out in the room a bit. Do you have the option of trying that?
I can't say I've had a similar experience regarding loose or muddy bass
when run that way. Sometimes clean bass sounds like less bass.
Might also check to see if the mids are OK (or turn them up a bit from "0").

[BMWCCA]

The L112 was never really intended to be used as a floor speaker. The whole point (as seen in the link above) was to basically make as nice a bookshelf speaker as JBL could, using the floor-standing L150A as the basis. Unless you're sitting on the floor, the whole thing could sound muddy since you're not getting the 044s anywhere near your ears. That's why those lovely (and pricey) JBL wooden stands tilted the boxes backward a bit. You also could have them too close together at about "4 ft apart" and you may want to make sure you have the mirror-imaged 044s to the outside at that small separation. I would assume any phase-reversal bass-cancellation issue might be exacerbated with the speakers so close but that's a layman's guess not based on science or even experiment.

I'm a big fan of the 128H, but my ears aren't using the same brain as yours are! I hope you can make them work for you. Then I use an EQ in every system in my house and love to tinker, mostly due to differences in how the source material was recorded and, or course, the room. My 4412As sound fine running flat. The L112s in another room I actually roll-off the bass a bit. My ears are tuned to a D130 from when I was a toddler so maybe I'm not as critical of the bass output as you are, either.

L112
L150A
4412A
030

[brutal]

I should have pointed out that my L112's have always been up off the floor with the LE5's at ear level. They do sound muddy on the floor or on short stands. The set in my HT setup are upright in bookcases 7-1/2' apart, 044's inward. The set in my home office are upright as well, but only about 3-1/2' apart, sitting on top of a pair of 4310 on short stands, set back into what was once a closet with the 044's outward.

According to GT's tech info, there's a rise of 3db in the 50-100Hz range when these are placed backs against a wall. They flatten out if you pull them away from any boundaries. I think that's where the "boomy" description arise from.

Let us now if you find anything amiss in the cabs or find improvements with some placement experimentation.

[porschedpm]

You might be asking the 128H to do something it was not designed to do. In my experience the 128H is a very flat speaker and doesn't have an accentuated that, say, the 2214 or even the 2213 do. If you're looking for more "bass slam", have you considered a subwoofer?

[toddalin]

Mine didn't always sit on the floor! Even so, I thought they could be a little "brighter" with more dynamic impact.

[Audiobeer]

I agree with Todd. I was never a fan of these and always thought maybe it was the pair I had. They were great in the Mids and highs but felt it was missing the punch that a lot of JBLs of that time had.