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JBL L100 Classic Bookshelf Loudspeaker Measurements & Conclusion


L100 outdoor testing

The JBL L100 Classics were measured in free-air at a height of 7.5 feet at a 2-meter distance from the microphone, and the measurements were gated at a 9-millisecond delay. In this time window, some resolution is lost below 250 Hz and accuracy is completely lost below 110 Hz. Measurements have been smoothed at a 1/12 octave resolution.

L100 Classic Spin o rama

The above graph shows the direct-axis frequency response and other curves that describe the speakers’ amplitude response in a number of ways. For more information about the meaning of these curves, please refer to our article Understanding Loudspeaker Measurements Part 1. At a glance, the response is not as neutral as we have come to expect from other modern JBL products like the HDI-3800 which had a terrifically flat response. The major linear deviations occur with a dip at around 1kHz, and two resonances at around 2kHz and 5kHz. The peak at around 5kHz would stand a chance of being glaring - if these speakers were listened at an on-axis angle. However, that is not the way they are intended to be used, so the above graph is potentially misleading. We will discuss this a bit more below.

L100 Classic 3D waterfall response

L100 Classic 2D waterfall response

The above graphs depict the L100 Classic’s lateral responses out to 90 degrees in five-degree increments. More information about how to interpret these graphs can be read in this article: Understanding Loudspeaker Review Measurements Part II. In these graphs, we get a better look at what exactly is occurring at off-axis angles. One thing to note is that some of the resonances don’t quite hold across the front hemisphere of the speaker. There is nothing wildly uneven, however, there is a bit of waviness here and there, and it is angle-dependent. What that means is that this wouldn’t be an easy speaker to equalize with precision. Since the overall response holds to a relatively even baseline, you could do broad equalization with tone controls to control its sound. The front-mounted tone controls are somewhat capable of doing this, and we will show their results below.

L100 Classic Polar Map

The above polar map graphs show the same information that the preceding graphs do but depict it in a way that can offer new insight regarding these speakers’ behavior. Instead of using individual raised lines to illustrate amplitude, these polar maps use color to portray amplitude and this allows the use of a purely angle/frequency axis perspective. The advantage of these graphs is they can let us see broader trends of the speaker’s behavior more easily. For more information about the meaning of these graphs, we again refer the reader to Understanding Loudspeaker Review Measurements Part II. In this graph, one interesting aspect that leaps out is the asymmetry of the off-axis dispersion. We would expect this, naturally, given that the speaker itself is vertically asymmetrical, but it’s still interesting to see how that manifests itself. Much of the asymmetry happens from 600Hz to about 5kHz. Up to 16kHz, this dispersion pattern is actually quite broad. The waveguide on the tweeter is really doing its job in keeping the tweeter from beaming in high frequencies. That only works up to a point, naturally, but that point is so high up in frequency that it scarcely matters anymore.

L100 on-axis vs 30-degrees

The above graph compares the on-axis response to the response at 30-degrees which is typically where a listener would sit between the speakers when they are facing forward in a parallel direction. The user manual states that the speakers should be facing straight ahead instead of toed-in toward the listener, and in that case the direct response to the listening position is significantly more neutral than the on-axis response. This is how I listened to the speakers. I had listened to the speakers for quite a while before I had measured them, and I was surprised to see that resonance at 5kHz since I didn’t hear anything like that in my own listening. I am normally pretty sensitive to elevations in response in that area which makes the sound more sibilant. We do see a more peak at 2kHz at 30-degrees, but that may not be much of an offender since stereo crosstalk can often reduce the region around 2kHz from a comb-filtering effect (here is a paper that describes this phenomenon). While early-reflections will also play a big role in the spectral composition of perceived sound, the direct sound is still paramount, so I would encourage users to follow the user manual guidelines on speaker placement for the L100 Classics.

L100 vertical waterfall response

The above graph shows the L100 Classic speaker’s response behavior along its vertical axis where zero degrees is directly in front of the tweeter, negative degree values are below the tweeter, and positive degree values are above the tweeter.  It should be said here that the vertical response isn’t nearly as critical as the horizontal response, so an imperfect vertical dispersion is much less of a problem. This graph tells us that the most neutral response occurs on-axis, with the tweeter facing the listener. However, if you give or take ten degrees up or down from the tweeter, the sound should stay pretty steady. Outside of a +/-10 degree vertical angle, you do start to run into crossover cancellation nulls. What is surprising is how mild these dips are, in fact, many of the vertical angle responses are surprisingly stable for a three-way speaker of this type, especially one using 2nd-order crossover slopes. One possible explanation for this is that all of the drivers are mounted relatively close to each other on a vertical plane, since the drivers’ distance from each other is what exacerbates these nulls. The advantage of such good uniformity of vertical dispersion is that reflections will not differ much from the direct sound, so this is a speaker that will have more benign acoustic reflections from the floor and ceiling.

L100 low frequency response

The above graphs show the L100 Classic speaker’s low-frequency responses that I captured using groundplane measurements (where the speaker and microphone are on the ground in a wide-open area). This is a very flat and well-controlled bass response. I would guess from this graph that the port tuning happens somewhere around 40Hz where the low-end slope becomes steeper. The roll-off looks to start at 80Hz but is quite gradual until 30Hz, so this speaker looks to be asking for just a little bit of help from low-frequency room gain which it will surely get. A flat response down to port-tuning would have potentially yielded a bloated bass-response in-room. Most users in a typical room should be able to count on solid bass down to at least 40Hz and likely a bit lower.

L100 impedance

The above graphs show the electrical behavior of the L100 Classic speakers. As JBL states, these are 4-ohm speakers and consistently so out to 20kHz. I wouldn’t advise these to be driven by a budget amp, but then few people who do get a pair will contemplate doing that. We can see from the low-end saddle that the port-tuning frequency is around 35Hz. The much taller height of the first peak in the saddle shape indicates that the bass driver’s resonant frequency is much lower than that of the enclosure. Overall, this is not an especially tough load for a good amplifier, with the minima being just a hair under 4-ohms at just over 100Hz but with a somewhat steep phase angle. Whatever amp the user pairs this speaker with needs to be comfortable with 4-ohm loads, at least for loud listening. I measured sensitivity to be 90.2dB for 2.83v at 1 meter. That is very close to JBL’s spec of 90dB. That is relatively high sensitivity so they can get loud without a huge amount of amplification.

L100 grille effects3

The above graph illustrates the difference that the grille makes in the on-axis response. It is not a completely transparent grille, but it doesn’t change the response that much. The difference is due more to the frame than the Quadrex foam cover. I included this for those who are curious about the effects of such an unusual grille. Common grille effects are discussed in this Audioholics article: Speaker Grilles On or Off: Which Way Sounds Better? 

L100 HF knob effects

L100 MF Knob Effects

 The above graphs exhibit the effect that the front-mounted tone control knobs make. Curiously, there is a lot more room to lower the response than raising it for both the mid and high-frequency knobs. The overall flattest response seems to occur with the knobs set to zero as would be expected.


l100 hero grilleThe JBL L100 Classics prove that fun and high-fidelity can exist at the same time. Many other “fun” speakers crank the bass and treble for an exciting sound, but that kind of sound grows wearying fast, and it is no good for content that strives for realism. The JBL’s sense of fun comes from the dynamic range enabled by the design of the unit as well as its splashy retro look. Good sound doesn’t have to come from audio components that look so serious that they would be at home in the inner sanctum of a cathedral. The L100 Classics look like they are good rock’n’roll speakers, but the truth is they are just good speakers for whatever you throw at them.

Let’s now briefly go over the pluses and minuses of the L100 Classics, and, as always, we will start with the minuses. One potential minus of owning them is the somewhat awkward form factor; they are too short for floor-standing speakers but awfully big for stand-mount speakers. As was discussed before, JBL has stands for them that are pretty sensible considering their size and shape, but outside of those, you are going to want a heavy-duty but short speaker stand for them; they need fairly particular stand criteria to work well.

If you want a speaker that looks like it can rock but actually can rock and do so with finesse, the L100 Classics are a terrific choice.

Another minus is that the response isn’t as neutral as other speakers from JBL that can be had. If you are interested in sheer accuracy, the HDI series or 7 Series Reference monitors are a better choice. This is not to say that the L100 Classics are badly inaccurate, but the response is a bit ragged compared to JBL’s designs that aren’t bound to a 50-year old form factor. The L100 Classics are a far more capable and higher-performing speaker than the originals, but some of the design cues that the L100 Classics are obliged to follow from the original L100s do constrain what JBL can do for a performance profile.

l100 badge close upOne potential minus is an obvious one: the aesthetics are a love-it-or-hate-it deal. Few people are going to see the L100 Classics and be on-the-fence about their appearance. I quite like them but they aren’t going to be an easy fit into homes that are going for an austere interior decor. 

With the minuses out of the way, let’s go over their highlights, the first of which is their sound. The L100 Classics may not measure perfectly, but they sound terrific nonetheless. A look at the basic on-axis response wouldn’t do justice to them, and a deeper look at their overall acoustic behavior gives a better indication of their sound. When used as recommended, they give a full, natural sound that is balanced and open. They have a wide dispersion that makes for a broad soundstage and spacious sound as well providing coverage over a wide area over their front hemisphere. Their dynamic range is on another level from most home audio loudspeakers, so if you want something that can get loud without compression or distortion -especially in the bass range where loudspeakers most commonly begin to exhibit dynamic range limitations- the L100 Classics are a great choice. They don’t need a tremendous amount of amplification to get loud either.

The L100 Classic’s low-frequency extension is very good, and if you enjoy bass-heavy music at loud levels, they will do nicely. The real star of the show here is that 12” woofer; there is not much it can’t do. With port-tuning at around 35Hz, there isn’t much music bass that it is going to miss, even for bass-heavy electronic genres. It is such a capable driver that a normal subwoofer would be more likely to degrade the bass than add, even if it had lower-frequency extension. The reason is that it would take a serious sub to match the dynamic range of the L100 Classic, and an average subwoofer would choke at the kind of mid-bass dynamics these speakers can do in that same frequency range. I would be looking at some of the better subs starting around the $1000 range that could actually make a positive contribution to a speaker like the L100 Classic if you wanted to extend the low-frequency response of the system. I should add that with all the praise of their bass ability, the sound wasn’t bass heavy but rather it could reproduce bass with remarkable authority.

l100 bass driver  l100 grille off on angle2

The build quality is very good. The drivers are serious when you examine the motors and overall construction, and the capacitors and inductors in the crossover circuit are real chonkers. The cabinet might have used a couple more braces, but I’m not sure how much good that would have done, and the speaker was already very heavy at nearly 60 lbs (that’s around 27 kg for all you metric-system kids for whom easy division by ten is all the rage).  

The JBL L100 Classic is an eccentric speaker but one that is very easy to enjoy. Older audiophiles who grew up with the original L100 Century speakers are sure to enjoy this new iteration, and younger audiophiles with a taste for vintage styling are going to enjoy the powerful sound. As was said before, it is not a speaker for everyone, but if you have read this far into this review, you surely know where you fall on that divide. I, for one, had a great time with them, and everyone that I showed them too were quite enamored with the unique styling as well as the impressive sound. Since times have changed and so have tastes, I don’t think JBL will see the kind of sales with these that the original L100 had. However, I do think that if more people get exposed to the sight and sound of the L100 Classics, JBL will certainly have another hit on their hands.

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
Build QualityStarStarStarStar
Treble ExtensionStarStarStarStar
Midrange AccuracyStarStarStarStar
Bass ExtensionStarStarStarStar
Bass AccuracyStarStarStarStarStar
Dynamic RangeStarStarStarStarStar
Fit and FinishStarStarStarStar
About the author:

James Larson is Audioholics' primary loudspeaker and subwoofer reviewer on account of his deep knowledge of loudspeaker functioning and performance and also his overall enthusiasm toward moving the state of audio science forward.

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Recent Forum Posts:

Kvn_Walker posts on May 04, 2021 10:49
shadyJ, post: 1480851, member: 20472
Keep in mind that is about how much the originals cost when you adjust their prices for inflation.
Very true… probably why I'm content with looking for deals on yesterday's high end. If I look at some of the best vintage speakers I've bought over the past year or so (Allison CD-9, Paradigm bipolar, Cambridge SW Towers, VSA VR-4, PSB Stratus Gold), they would all be $3000 or more if still sold today.

Heck, the Von Schweikert VR-4's were $3k when introduced 25 years ago. They'd cost more than my car did if they were still in production.
Kvn_Walker posts on May 04, 2021 10:38
Irvrobinson, post: 1480938, member: 6847
I read the review, so I know the new ones have some merit, even though it is a little questionable for the price. I also know the drivers, crossover, and overall design are far superior to the old ones I'm bitching about. Nonetheless, being honest, if you designed the best $4K/pair speaker you could right now, would they look anything like the speakers you reviewed?
They'd probably look like the BMR towers.
Irvrobinson posts on May 04, 2021 10:30
This thread sent me down memory lane in a way, so I tried to remember the people I knew between about 1977 and 1987 or so who owned L100s. Scribbling them down, I counted eight, not “about ten”. Oddly, I remembered all of their first names, but only three last names. Weird mental block. Two of the three last names I remembered were the owners who put their L100s on stands, so perhaps I have a speaker stand thing going on I'm unaware of. Two other thoughts came to mind. First, even at eight owners I've known, I can't think of another speaker model I've run into with as many owners I've known over time. I do remember thinking after I moved to another city after college for my first career job, and meeting more people with L100s, that the L100s were a phenomenon I was oblivious to. Second, it occurred to me that I don't remember any woman I've known well enough to be in her home, and didn't live with a man, to have an audio system that I remembered. None.
D Murphy posts on May 03, 2021 23:40
shadyJ, post: 1480992, member: 20472
I'm not trying to dance around JBL's feelings here if that is what you meant. The L100 Classic is not a perfect speaker. The peak at 5kHz is probably due to a crossover issue,,,,
Looks to me like it's more of a marketing issue. I'm sure the EE's at Harman could fix the peak if they wanted to, or were allowed to, without blowing what seems to me to be a very generous price target.
Swerd posts on May 03, 2021 22:45
D Murphy, post: 1480990, member: 88657
Can't say as I remember the imaging conversation. But I'm pretty sure it was more than two hours ago, so that would explain it. It's hard to imagine the JBL imaging very well at any volume given the screwy driver configuration.
Dennis – thanks for chiming in. I still occasionally get info requests from L100 owners who want to build your crossover. In the past month, I've had two.

I never said the JBLs imaged well. Only that they could actually produce images if the volume was high enough. Your crossovers did well at improving that at somewhat lower volumes. But it couldn't compare to any of your own designs that I know well, the CAOW1, SongTower, or Veracity ST. While you had one of my L100s at your house, I put my small CAOW1s on kitchen stools in the family room for music and movie use. We both noticed how much better they sounded, despite their noticeably less bass. A few years later, when I first got SongTowers, their imaging, at any volume, easily out did the modified L100s. After that, I had no nostalgia whatsoever for the L100s.
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