This review is a very long time coming. I’ve had these on the trunk burner for a year, unsure if indeed they were the best budget speaker ever, or simply a colossal failure in material design. The reality ended up somewhere in the centre.

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as of May 16, 2022 3:09 pm
as of May 16, 2022 3:09 pm
as of May 16, 2022 3:09 pm
Last updated on May 16, 2022 3:09 pm

These speakers are big… you can almost fit three of small JBL LSR305’s within the volume of among the 308’s. That is stupid massive for a desktop, specifically for my little office, which means this review is more centered on living room performance.

Some background information:
This is a little perspective as to the reasons this review is important. There can be an entire audiophile faction that believes in limited dispersion manipulated directivity speakers. The target because of this group is for speakers to have is bound interaction with the area. If you ask me this will provide you with more of a sense of being taken up to where the music was recorded rather than the recording occurring in your room. As somebody who likes studio recordings because of their perfection, and hates most live recordings because of their flaws and background noise I don’t possess much interest in speakers made with this goal. My reference system includes a ridiculously wide dispersion.

The thing here which makes this relevant is that the JBL LSR308 in some recoverable format is damn near nearly as good at handled directivity as other things on the market. The best way to measure managed directivity has been polar measurements. That is basically a number of frequency response measurements, walking the measurement mic around the speaker to observe how much the quantity decreases as you set off axis. An excellent result will show a smooth uniform fall off as fast as possible. This is a polar response measurement of the JBL LSR308’s taken by Dr. Earl Geddes, a guy with some serious music chops, demonstrated in this program that he wrote for displaying these measurements.

To quote the nice doctor, “For $200 that’s an incredible speaker. There are of course better speakers, but at $200 I don’t believe ever I’ve seen an improved speaker.” To clarify, that $200 number may be the average price for each and every speaker, and pair can cost you double.

All of that if you ask me is icing on the cake. I found the speakers because I was hopeful that they might provide full range audio tracks for cheap. The JBL LSR305’s are the least expensive naturally good sounding speakers you can purchase. Those speakers are smaller, don’t play as loud, and because they’re smaller they don’t have the pattern control that’s possible with a more substantial speaker. In addition they don’t play as deep, or with as much authority as a more substantial speaker.

The LSR308 is speced to play flat right down to 37Hz. That’s plenty for some music, and unlike other manufacturers JBL Professional will not bullshit it’s specs. The LSR305 does 43Hz, which is quite deep for just a little speaker, but as I noted in my own review they stumble when asked to execute at volumes needed when partying in larger rooms.

So now which you have that little bit of background info, you can observe there is a whole lot of hype and expect this speaker.

Waveguide Tweeter
The waveguide design is pulled from the flagship JBL M2 system, when using a tiny button magnet soft dome tweeter rather than a compression driver. The bigger the waveguide the more directivity control at lower frequencies. This waveguide is pretty big, and really should control horizontal directivity right down to about 2500Hz.

Look at all those inches, 8 to be exact. The cone material is some form of polymer-coated aluminum or some such. I believe it is the same material that Infinity uses on it’s Primus type of speakers. The butyl rubber surround insures an extended life, and isn’t overly stiff.

Like all Harmon speakers I’ve reviewed this woofer includes a backing magnet. I did so figure out that is for a lot more than magnetic shielding, in addition, it escalates the BL of the driver. The bigger BL signifies that the driver includes a higher acceleration, getting where it requires to go fast with the excess little magnet.

Plate Amp
The plate amp take up the complete back of the speaker. It’s an enormous yet very thin little bit of sheet metal with a little amp screwed to the center of it. The Amp itself has plenty of watts. It’s a Class D amp that generates 56watts for the tweeter, and 56 watts for the woofer. I did so get somewhat of hiss only using unbalanced consumer grade sources and the gain turned completely up, nonetheless it wasn’t too bad with the speakers a few feet away.

The cabinet is a box with out a front or a back, it’s very good thickness MDF, but no bracing inside at all. Giving the medial side a knuckle wrap will leave you feeling hollow and unsatisfied. The 1/8 inch thick plastic front baffle and 1/16 inch thick unbraced metal back plate makes this the worst cabinet I’ve ever seen from a material selection stand point. The trunk panel flexes quite a lttle bit when inserting the energy plug or 1/4 inch jack. The wave guide reaches least an extremely stiff structure, but tapping on the waveguide you can feel having less material behind it.

I wish JBL could have talked to the Infinity Primus team about cabinet construction and gone for a bit more beef or bracing.

It offers a port on the trunk of the speaker, which is comically mounted to the sheet metal back. The port itself isn’t too deep, and pretty wide. A lot more than any speaker I’ve tested up to now these speaker have to be from back walls, if that can’t happen you then have to flip the -2dB activate the trunk of the speaker to drop the bass response since it may easily smother the midrange.

Office Setup Listening Notes:
I had the 308’s in my own little 7 x 11 foot office in the beginning plus they just over powered the area with way too many bass, rather than enough placement options to get anything right. Here are a few of the notes I took from those sessions.

Break apart before they get loud. Scrambled like they are too large for the area, directivity can’t fix the stupidity of putting these speakers in this tiny room.

I keep checking the SPL meter and it’s really only reading out 85dB but it’s just packed with music, losing definition.

The exceptions will be the audiophile fare of music where its a couple of instruments playing. If the music isn’t busy they excel like nothing in this cost range should.

There seem to be to be issues with the most notable octave sounding hot. Also, the speakers can appear to be they are yelling at the listener, which is something I find true with all horn/waveguide speakers.

Serious bass, but you’ll not be wondering where in fact the subwoofer is, the foundation of music is actually these massive boxes. These sound boomy too me, but most deep playing rear ported stuff does unless its 3 ft from any walls.

These need work, a sweep test shows the trunk amp panel using one speaker is rattling when 140-200hz is played. JBL said that they built these as cheap as possible, plus they weren’t lying. On the plus side you get the leading edge of tech for peanuts.

Male vocals are over emphasized an excessive amount of bass in to the 200-400hz range despite having the -2db switch flipped.

Does EDM like nobody’s business – Simian, Orbital, etc. These will surely be party speakers.

Living Room Listening Notes:
After limited success at work the JBL LSR308’s spent two months in the living room. The wife really appreciated the excess clutter. These were installed right to my Logitech squeezebox as a source and I did so not run them with my subwoofers, that have been only used as stands.

With the limited horizontal dispersion the speakers felt these were too near me.

Tone of some lower treble seemed muted, as it isn’t blasting out of your side of the speakers, but details were plentiful.

Vertical dispersion was excellent in comparison to my main rigs ribbon tweeters extremely limited vertical range.

Deep bass in this space didn’t feel defined. It had been playing the notes, but felt similar to it had been pushing air than providing impact.

As the quantity crept over vocals levels the low midrange started to break apart. Rather than being smothered by bass like at work it was not clear at volume.

After some spirited listening the rattle from the left speaker has gotten worse. That is absurd, even for cheap speakers.

I really feel that the caliber of the cabinet construction, a thing that I don’t believe effects the sound near just as much as persons give it credit for, is in fact ruining these speakers. There is indeed much the following that having something this simple be this wrong is not simply disappointing, it’s upsetting.

Back to any office for some measurements.
Frequency response looks amazingly flat over the most the response. Remember that my room modes are wonderfully random in this small room. Anything below 700Hz is more of a indication that the speaker does something at those frequencies than a sign of quality.

The top octave(10kHz-20kHz) is quite particular to measurements, being off axis simply a few millimeters would provide a slightly different response. That is probably a function of the transition from the dome tweeter, to the waveguide. This is simply not really audible because human hearing is quite shit in this range and +-3dB up there is nearly impossible to determine. The low midrange and bass are slightly bloated even considering the randomness of the area modes. This measurement was finished with the bass switched to the 0dB setting. Switching the -2dB setting for bass could have helped even things out.

This can be the close mic of the drivers, the tweeter continues to be showing it’s ass, and it’s really still not a huge deal. Of note, there is some extra noise from the port which indicates internal rattling, but it isn’t very much.

DSP Correction:
I will usually execute a DSP correction for speakers to greatly help them be all they could be. With the JBL LSR308’s there is nothing to accomplish here. These speakers tonally are neutral. The problems that keep this speaker from perfection are classified as “other” and linked to the implementation of the look.

If you are limited by close boundary placement and the -2dB bass switch isn’t performing of freeing up the low midrange from the boundary gain you can test a 1.0Q filter centered at 250Hz that requires a couple of dB out of your speaker.

The cabinet construction upon this speaker is indeed bad that it should be the problem… so it is arts and crafts time!

Let’s talk testicals for an instant. I’ve got a pair, plus they would have to be sized appropriately for another steps. These speaker’s could possibly be cheap, however, not that cheap and I was unsure of the results of the extremely everlasting modifications. As such may be the case I advise anyone making these modifications gets blind drunk before they attempt.

The first step, after drinking a huge amount of your recommended booze, is to take the speaker completely apart. First take away the trim ring and woofer, then undue the twist ties that contain the wires aside of the box. Then flip the speaker over and unscrew the plate amp, take away the connector for the tweeter and front LED wires. You can now remove the tweeter, and move on to focus on the six 3 inch long baffle screws that are hidden behind the foam that covers the sides of the box.

Second step, after procuring some bizarre foam that mimics the density of MDF mix a bit at a time by using a digital scale that the authorities would call drug paraphernalia. Quickly pour this tiny bit into among the a large number of voids on the trunk of the baffle, being careful never to make chaos, this shit it impossible to log off of the plastic baffle. Ok last one and you have about 45 seconds to get this done from enough time that you start mixing, so stop wasting time about it. Repeat from 25-40 times as needed being attentive to the temperature of the baffle, as the foam get retarded hot since it cures and I believe it might melt the baffle if a sizable enough batch was poured at onetime.

Success! Bask in the glow of the excess 3 pounds of material. The baffle is in fact pretty hefty now, and incredibly dead.

Third step, apply cheap brand-x asphalt backed aluminum onto the sheet metal of the plate amp. Ensure that you cover all surfaces, overlapping seams and scraping the top down with something similar to a debit card or putty knife once everything is set up.

Finally, put everything back, aside from that wire for the energy indicator LED. We don’t need that.

Modified Listening Impressions:
After sleeping off the beer and fumes of the curing foam I felt very pleased with my now chunky JBL LSR308’s. I hauled the speakers back the their perches on my subwoofers and sat down for a listen.

Welp, these sound the same. Same nitpick with the midrange clarity at volume.

No rattle, which is great news, but might have been accomplished with an RMA.

Modification Measurements:
Showing the unmodified and modified measurements hand and hand – these measurements are closer than most left and right speakers from the same pair.

Nothing to see here.

Once more in to the Living room
In a final ditch attempt I used brute force to help make the speakers better. I crossed the to my subwoofers.

This is simply not what I needed to do here. I needed great speakers that might be as effective as any other at making a wide selection of sounds at a steady volume with clarity. I needed something to get rid of the chase. Instead we are left with a pricey fix to an inherent problem on a damn good, however, not perfect, speaker.

Crossover duty was performed by a minidsp, and the subwoofers were powered by my Behringer iNuke amp. I mimicked the crossover entirely on most A/V receivers – by using a first order on the high pass, another order on the reduced pass and centered the crossover at 80Hz.

With the reduced frequencies bought out by the subwoofers, the JBL’s sound sublime.

If someone is trying to find controlled/limited dispersion they are the speakers to get. They get loud and stay clean, plus they do everything that’s asked of them.

Final Thoughts:
This speaker design asks a whole lot from the woofer. It’s likely to play clean and flat right down to 37Hz, control directivity of the midrange, and crossover cleanly to the tweeter. I’ve never heard a two-way speaker that played as clean and deep as an excellent three-way, and they are no different.