I have been a huge fan of the Infinity Primus line for about a while now, I've used them in 2 different home theater set ups with great results. The reputation of them online is pretty dang high and in my opinion very well deserved. At their often occurring sale prices, I don't know of anything that can beat them. With that said, at full retail, the competition if much deeper and other options should also be considered if you are willing to spend that much.
I haven't been able to find much about the JBL Loft series online, in fact they don't seem to be a product featured on the JBL web page. But they are sold at Fry's and Amazon and carry a regular price point that would have them compete for the same audience with the Infinity's.
So knowing that JBL and Infinity are both owned by Harman Kardon, both are intended as small bookshelf or surround speakers, both use 4 inch mids, and that they both retail for similar prices; currently $128.49 for the pair of JBL Loft 30 and $59.99 each for the Infinity p143 on Amazon. I thought they would make for a comparison and review.
Detailed speaker disassembly picture album
JBL: Small very basic looking almost square bookshelf speaker. Has a real xover, not just a cap on the tweeter. vinyl wood is clean if uninspired. 5 way biding posts that will accept banana plugs. Very light weight, cabinets are constructed from 1/3 inch MDF
Infinity: Significantly bigger than the JBL, similar black wood grain vinyl but almost semigloss. Nice binding posts but do not accept banana plugs without modification (or so the internet has said) Basic black grill but nicely presented and curves over the top of the speaker. Much heavier than the Loft 30.
Acoustic Guitars - Arabesque - 5 Eiffel
I love this song because there are a few portions that remind me of a song from the movie Serenity. But this isn't about the greatest sci-fi movie of the last 15 years, it's about bargain speakers. In this example the Infinity p143 sounded very good, though they might be missing a little something to get some of the deeper cords and drumming against the guitar but it seems to be inline with what would be expected from a 4 inch driver. The JBL Loft 30's sounded very different, bloated mid bass give the impression of slightly deeper bass but at sacrificing a lot of detail. I also found the tweeters to be on the harsher side of things.
Adele - 21 - Rolling in The Deep
I found a pretty big difference in the vocal quality and imagine between the two speakers. The Primus' were pretty neutral sounding it sounded just like Adele should sound. Vocals weren't too forward or recessed. The Loft 30's were a whole other story. Immediately when AB testing, when switching to the Loft's its like the wind was knocked out of your ears for a second or 2. There is some small cymbal or tambourine throughout the song that just gets lost in the Lofts. I think its a combo of the in inflated midbass and something funky with the tweeter. Adeles vocals are way in the back and have a nasally quality to them.
Buffalo Springfield - Stop Children What's That Sound
This is admittedly a terrible quality MP3 that I have, we are talking Napster 1.0 128kps bad. But I wanted to play something old. Again the differences between the 2 speakers is immediately apparent. with the Lofts the vocals sound like they are coming out of a cave, they are unnaturally deep and without detail.
The Civil Wars - Barton Hallow - Billy Jean
Love this song. And it sounded great on the p143. Imaging seemed strong and centered John Paul White's vocals. This song was a bit of an anomaly. As the sort comings of the Lofts were not as apparent for much of the song. The into is a little bloated with the Lofts, but its John Paul White's voice that gets some obvious resonances. This was even worse when listening to the title track. So while the Lofts fared better, they still were the losers.
Katy Perry - Prism - Dark Horse
By now I've gotten a good feel for the comparison between the two speakers. The bass note in the song isn't all that deep and the p143 handle it pretty well. All the bad things about the Loft 30s shows up again. Inflated midbass that gets muddy a causes everything else to sound washed out. Vocals are recessed back and just a blog as far as imagining goes.
The JBL Loft 30's have a brighter slightly harsh tweeters, maybe a tiny bit deeper bass pretty muddy and carries into the mid range. Maybe tuned to give an artificial depth to the bass? Some noticeable resonance int he male vocal range. (Petey Pablo - part 2 - Still writing was a huge example of this). I also feel like the Infinity throws a bit wider of a sound stage and image better. Often the JBL's were just one smear of sound, where as the Infinity's had the ability to place the artist in front of you. Doing a much quicker AB testing with the Dayton b652, the Dayton best the JBLs. While there are still flaws in the b652, at the price it beats the JBL Loft 30. The comparison between the Dayton b652 and the Infinity p143 is much closer. Between the, the Infinity is the better more refined speaker that keeps it composer better particularly in the upper registers.
The frequency response graphs on the highlight the muddy bass and lower midrange on the JBL Lofts; while the Infinity Primuis p143 was incredibility flat. I would challenge anyone to find a better speaker pair under $100 new.
GRAPHS AND STUFF
Above you can see the difference in listening position frequency response. The Infinity p143 are much flatter throughout the range. Darn close to +/- 3db from 100hz to 16khz. I was a little surprised that the tweeter didn't have a little farther extension but it's so much and with such a steep drop off, I'd question just exactly what you would be missing. The JBL Loft 30 has a noticeable hump from 120hz to 250hz, which is what I would attribute to the muddy sound of the midbass range.
Above is the individual driver responses of the JBL Loft 30. It seems to use a much lower and shallower cross over point around 1.75khz
Addtional Frequency response graphs album