JBL 4329P active loudspeaker

Hi-fi is at a crossroads. One road takes us toward modernized versions of the gear we grew up with, stuff that has been around since the 1950s. The other road faces the future. While sometimes accommodating physical media, including vinyl records, that's not where that road leads. On that road, streaming is the norm, and equipment may be hooked up with traditional signal cables or with no cables at all, just GHz-range electromagnetic radiation, the digital kind. In the more extreme cases, the music may remain digital all the way to the amplifiers, which themselves are likely to be class-D.

I keep a foot on both paths, hoping they don't diverge so much that they split me in two (footnote 1). I've got a substantial collection of physical discs, black and silver, and I play them often. But I love the convenience of my network-attached storage (NAS) appliance, Qobuz, even lossy Spotify, especially when I want my world filled with music for hours with no thought or action on my part.

I do still play CDs—I wasn't lying when I wrote that—but many of my CDs sit on shelves collecting dust because I long ago extracted their data, now stored as lossless rips on a NAS. I listen to those more often, played back on my dCS Bartók streamer/DAC, mostly via the dCS Mosaic app. It's the same for LPs: Some still get spun occasionally, but many of them have been ripped—needle-dropped, digitized, and loaded into the NAS. They get "spun" far more often in that form.

We all have roots in the past; that's the nature of things. But new technology is cool, and the future is streaming and wireless. I try to stay curious and, as I said, to travel both roads.

The product I'm reviewing, JBL's $4500/pair 4329P powered loudspeaker system, has its wheels on that future-facing road—or would if it had wheels. It can work as a self-contained, all-in-one wireless hi-fi system in a home without physical media, or it can connect to any "legacy" media source: a record player, a radio tuner, a CD player (via an analog or digital connection)—even a television or cable box. They don't need to be physically connected to anything but power—not even to each other: A wireless connection is just fine up to a maximum data rate of 24/96. Tether them with the supplied CAT5e cable, and you can play music stored in PCM files at resolutions up to 24/192; these JBLs will even decode MQA. DSD is converted to PCM; then you can play that, too.

A gadget with woofers and tweeters
JBL is one of the oldest speaker companies that still makes speakers, so let's start there, dig in, and see what these JBLs are all about. Each speaker is contained in a hefty (about 35lb), slightly bulky (20.3" H × 12.6" W × 12.7" D) wood-veneer cabinet. The main speaker, which has more electronics inside it, is slightly heavier than the other one. They are of bass-reflex design, with ports in front below 8", Model JW200P-4, "pure-pulp black" paper-cone woofers "with cast-frames." The tweeters are model 2409H "1-inch annular ring Teonex-diaphragm compression drivers with advanced HDI geometry horns." That's a modern take on the traditional paper-cone woofer paired with a horn-recessed polyurethane tweeter. The crossover, which is digital, is at 1675Hz, which places the nine highest full notes on the piano and a few top violin notes above the crossover. Each driver has its own amplifier, 250W for the woofer, 50W for the tweeter.

Sporting a retro, classic-JBL look, the 4329P is available in "Natural Walnut," "Black Walnut" (black with some visible wood grain), and, unveiled at Munich High End, "Matte White."

Purely as speakers, these are an updated iteration of what JBL has been doing for decades. It's the electronics that add something new and different.

JBL's marketing materials don't tell the full story, so, to help wrap my head around the gadgetry inside the 4329P, I got on a Zoom with Jim Garrett, JBL's senior director of product strategy and planning. Here's what I learned.

These JBLs employ digital amplifiers that use AX5689 "digital audio converter and amplifier controller" chips from the Dutch company Axign (footnote 2). The analog line inputs undergo A/D conversion soon after entering the chassis, to minimize signal degradation. The crossover is digital; this and all other digital signal processing takes place in the Axign processor, including D/A conversion: As Garrett stated, "there is no DAC chip." In effect, the whole system is a DAC.

To get inside this gadget (footnote 3), digital signals may take several routes: Bluetooth, Wi-Fi, wired Ethernet, USB, optical S/PDIF (aka TosLink, with the newer kind with the "swinging door" in place of the invariably misplaced dummy plug of yore). They all work.

When they're not connected together with the included CAT5e cable and connected to a music stream by Ethernet, the speakers generate their own Wi-Fi network to communicate with each other and stream music. By the time you read this, JBL says, an app will be available to help you sign the speakers onto your Wi-Fi network. But it's not available yet, so I used the web interface, which includes a tab to sign on to your Wi-Fi network (footnote 4). Also buried in the utilitarian (but sufficiently clear) interface is a primitive player app that I easily connected to Minim-Server, which is running on my NAS. This allowed me to directly access my home server—an important undocumented (or under-documented) feature! I can play all my music with the JBLs! If I heard Garrett correctly, the phone app will include a network player and server-access setup capabilities.

The JBLs will work with Roon over Wi-Fi and/or Ethernet. I used them both ways, with equally trouble-free results.

JBL's marketing materials make a point to say the 4329P works with both Apple AirPlay 2 and Google Chromecast. (JBL's parent company, Harman, is owned by Samsung, the largest maker of phones running Google's Android operating environment.) I had no way to test the Google stuff, but I was able to use AirPlay 2 over Wi-Fi with both the Spotify and Qobuz apps, streaming from my iPhone 7S and a recent-generation iPad. AirPlay 2 offers CD-rez music transmission—lossless—and because AirPlay piggybacks on Wi-Fi, proximity limitations aren't as strict as for Bluetooth. You can stream to the speakers by AirPlay from across a large house on the same Wi-Fi network, whereas Bluetooth doesn't work much farther away than an adjacent room.

Analog sources connect via a 3.5mm TRS socket for unbalanced—don't worry, cables and adapters are available—and a combo XLR-balanced ¼" TRS jack for balanced signals. All connections, digital and analog—all except one power cord—are on the rear of the primary speaker. A switch lets you assign the primary speaker to L or R, which is convenient for placement of source components and cables. A switch allows 3dB of rolloff of the low frequencies for more natural bass when the speakers are placed against a wall. Finally, there is a subwoofer output over an RCA jack. Connecting a subwoofer automatically rolls off the built-in woofers at 80Hz.

In addition to the 4329P speaker system (packed together in a single, 80lb double box), JBL sent the accompanying JS-80 metal stands. Everything unpacked quickly in the garage, and in a few minutes I had them inside and set up in a small space next to my studio, no wires except the two power cables.

The speakers arrived prepaired, wirelessly. They found each other within a few seconds of power-up, the front-panel LEDs changing from red to green. I pushed the Bluetooth symbol on the small plastic remote control and the speakers went into Bluetooth-pairing mode. My iPhone found them and paired right away.

Voilà, just like that, I was streaming lossless music from Qobuz. This is the simplest way to use the 4329P, and Garrett said some users will never do anything else. But this is an audiophile magazine, and I knew the 4329P could do more, so I kept exploring.

Worth noting: Among the modes of streaming from a phone, or from Roon via phone or desktop remote, the JBL remote can be used to pause/play and go to prior or next tunes in a queue or playlist. The primary speaker also includes volume up/down, source selection, and of course power on/off; there is a volume control knob and a source-select knob on the front panel. The only other control interface on the speakers are LEDs indicating that power is on and that the speakers are communicating with each other, and LEDs on the primary speaker indicating the input source.

Wanting to move on to highest-resolution playback, I connected the speakers together with their CAT5e tether and plugged an Ethernet cable into the primary speaker. I selected the network/streaming input on the JBL remote and fired up Roon software on my office desktop computer, which was set up as a Roon Core. It found the JBL speakers on the network, noting that they were not "Roon Tested" but were available as a designated endpoint. I selected them and started streaming music from my own library and Qobuz. Although JBL folks didn't say the speakers needed break-in time, all new woofers, in my experience, benefit from some limbering up, so I played music for hours on end for a few days. By the third day, the bass was sounding deeper, fuller, and less like it was pushing against the tide. The horn tweeters seemed a little less jangly, and the bass-treble balance settled in. I felt refreshed from all the hard rock, metal, and old-school hip-hop I'd played as the speakers worked out their birth pangs.

During the break-in period, I tested the USB input, using Foobar2000 on my laptop with a portable USB drive containing a mirror of my server library. I can't say I heard much of a difference playing the same songs over USB compared to playing over Ethernet from the Roon Core on my office desktop computer using the Roon streaming player. Perhaps the laptop USB playback was a tad crisper and clearer, in all the good ways, but the differences were subtle and could well be imagined. Both USB and Roon-over-Ethernet sounded superior to all-wireless Bluetooth from the iPhone, more full-bodied and realistic, less 2D-plastic. No surprise. For critical listening to high-quality recordings, a wired connection with Roon is preferrable. But think about how easy it is to take these two speakers out on the porch or patio, plug them into AC power, and stream an evening of party music from a phone in your pocket!

JBL created a Qobuz playlist specific to this speaker, described as "the (songs) that the JBL engineers at the Harman Center of Acoustic Excellence, located in Northridge, CA, used during the voicing/tuning process for the JBL 4329P" (footnote 5). I listened. Not all this music is to my taste, but the variety of styles and instrumentation gave the speakers a good workout, revealing their sound as subjectively full-range—and that it is not reserved. Their voicing reminds me of some other modern speakers, seemingly tipped up a bit though not, in this case, to an annoying extent.

Footnote 1: Which seems especially challenging when one road is going forward in time, the other backward in time, but never mind.—Jim Austin

Footnote 2: See bit.ly/3Jt5Ma3.

Footnote 3: "Gadget" has different definitions and connotations across English-language dictionaries. The Cambridge Dictionary is typical of the British viewpoint, and somewhat complimentary: "a small device or machine with a particular purpose." The Merriam-Webster Dictionary, which is American, offers a slightly pejorative edge: "an often small mechanical or electronic device with a practical use but often thought of as a novelty." The 4329P is a "gadget" in the British sense: It may be novel, but it is not a novelty.

Footnote 4: To access the speakers' web interface, you need to access your network router. Look for devices on the network, note the IP address of the speakers, then access that IP address by typing it directly into your web browser. Among the many useful features of the web.

Footnote 5: See bit.ly/44Cd6Zd.

JBL, Harman International Industries
8500 Balboa Blvd.
CA 91329
(800) 336-4525

JRT's picture

John Atkinson stated, "With the 4329's low-frequency boundary compensation set to "Flat," the woofer's nearfield response (fig.2, blue trace) has its reflex notch, which is when the back pressure from the port resonance holds the cone stationary, at 30Hz. The output of the twin ports (fig.2, red trace) peaks slightly higher in frequency. Their upper-frequency rolloff is initially clean, though some low-level resonant peaks are present between 500Hz and 900Hz. The high-pass rolloff of both the woofers and ports below the port tuning frequency is much steeper than the usual 12dB/octave; presumably there is a series high-pass filter in the woofer feed to minimize subsonic excursion."

I am sure that you know the subject matter, but you need to fix what you wrote, and then feel free to delete my comment.

It is not "pressure from the port resonance" at 30_Hz, but rather from the Helmholtz resonance associated with the bass reflex alignment which reduces cone excursion to a local minimum near 30_Hz, shown in your figure 2. The physics of the Helmholtz resonance and port resonances are very different. The port resonances are clearly shown in the 1.5 octaves below 1_kHz (approximate).

Also, a bass reflex alignment is a 4th order acoustic high pass, 24_dB/octave at low frequencies well below the acoustic high pass corner. A sealed alignment is 2nd order, 12_dB/octave in free field at low frequencies where wavelengths are much larger than baffle geometries, or on infinite baffle firing into half space, 2pi spherical. As compared to sealed alignment, bass reflex alignment cascades another 2nd order set of poles in the S-plane, resulting in the 4th order acoustic high pass.

I agree that this JBL exhibits a much steeper high pass, and that they have cascaded electronic filter(s) which both steepen the high pass and exhibit a high Q to increase port output in the vicinity of the Helmholtz tuning, while thecsteepened slope reduces woofer excursion where it would more usually unload below that tuning frequency. Not sure what they might be doing in DSP, but there may be a lot of phase rotation associated with that steep high pass, and since group delay is the negative rate of change of phase with respect to frequency, that group delay might be excessive near and above that steep slope and sharp corner.

The port resonances are not sufficiently suppressed below the direct response from the woofer diaphragm and are polluting the midrange.

John Atkinson's picture
JRT wrote:
I am sure that you know the subject matter, but you need to fix what you wrote, and then feel free to delete my comment.

I'm okay with keeping your comment on-line.

John Atkinson
Technical Editor, Stereophile

teched58's picture

Any comments on what JRT is saying?

MhtLion's picture

Too long. I didn't read.

remlab's picture


MhtLion's picture

Great review. I think JBL 4329P Active is a great lifestyle speaker, perhaps a glorious lifestyle speaker. I love the fact that they are active. A couple recommendation for the manufacturer. HDMI for $100 more will suit the needs of many potential customers - at least that's the deal breaker for me. Second, I wish the finish is a bit better. I auditioned many modern JBL speakers. They all sounded good. But, everything under $9k seemed to have very cheapish looking veneers.

KellyP's picture

One of the most impressive things about the 4329P is its sound quality. The speaker system produces a very wide and deep soundstage with excellent imaging. The bass is deep and powerful, and the midrange and treble are clear and detailed. The 4329P is also capable of delivering very high volumes without distortion.

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