JBL HDI-3600 Speaker Review

The JBL HDI series of loudspeakers features an all new High Definition Imaging (HDI) Waveguide technology, designed to enhance acoustic imaging and smooth in-room response. The JBL HDI-3600 speaker is a compact floorstanding speaker that could find its way into most rooms. At $3800 a pair, the HDI-3600 is on the affordable side of high end speakers. Given the quality of sound these produce along with their understated, elegant design, the price is fair. Also part of the HDI series is the larger HDI-3800, a similar design but with 8” drivers, a small bookshelf (HDI-1600), center channel (HDI-4500), and subwoofer (HDI-1200P). This review focuses purely on a two-channel music setup featuring the HDI-3600.

Overall I found the JBL HDI-3600 produces a well-defined, neutral sound that is dynamic and precise. Their ability to create a believable soundstage with depth and presence allows the listener to get lost in the music.

JBL HDI-3600 Speaker Design and Setup

The HDI-3600 arrived in walnut finish, but is also available in gray oak and high gloss black. All three finishes are the same price and are top notch quality. The design is simple, yet elegant, thanks in part to the curved edges around the rectangular cabinets. At almost 39 inches tall, these are not small speakers, but they are slim enough to not dominate a room and are noticeably smaller than my Revel F208. The cabinetry is top notch on these speakers. The woofers and horn blend seamlessly with the smooth walnut veneer. At close to 62 lbs, I could move them around myself, but the HDI-3600 is clearly well built. Internal bracing makes for a solid feel, and most importantly, neutral sound performance. On the back are the two rear-firing ports and dual terminals for optional bi-wiring/amping. Magnetic grill covers attach to the front and extend the full height of the speaker. However, I prefer the look of these speakers without the grills on.

Three 6.5” drivers and a 1” compression driver make up the HDI-3600. The 6.5” drivers are cast frame, Advanced Aluminum Matrix cone woofers with 1.5-inch voice coils. The 2 ½ way design means that all three 6.5” drivers get low-end spectrum duties with one also taking on the mid-range as well. The real excitement comes with the patented 2410H-2 1” compression driver that sits inside a newly designed High Definition Imaging (HDI) horn. Looking closely at the horn you can see the pincushion effect creating the four seams and puffy curved walls that flair outwards. Every bit of the shape is deliberately designed in order to provide a seamless transition from the low and mid-range drivers to the high frequency compression driver and uniform dispersion for smooth in-room response. Frequency response is designed to be neutral on-axis and off-axis, helping to keep the same tonality in different seating positions, but also from in-room reflections.

I ran two setups with the HDI-3600. One in my small office powered by a Marantz SR7001 receiver and an Auralic Vega DAC with the speakers positioned about 6 ½ feet from my chair. The other was in my larger home theater room running off a Denon X4400H receiver as pre-amp and Wyred4Sound monoblocks. The speakers sat about 8 ½ feet from my listening spot.

Listening

I went in with low expectations for the office setup. It seemed like too small a room for a floorstanding speaker of this size. There’s no room treatments either so in my mind, the compression drivers would be way too bright and overload the room. My unsupported predictions were completely wrong! The JBL HDI-3600 offers excellent acoustics even in a small room. My ears were never fatigued while working and listening to music throughout the day. The imaging is excellent on the soundtrack by Jónsi for We Bought a Zoo. The percussive instruments on “Brambles” come from way outside the plane of the speakers, making my small office seem much larger than it is. The HDI-3600 is able to create much more depth to the soundstage than would be expected in a small room. Low-end performance is very clean and tight on Ellie Goulding’s “Slow Grenade” and the right amount for my office.

Radiohead – True Love Waits consumes the listener with the intimate vocals by Thom Yorke. A big front-forward, three dimensional image of Thom hovers in front with the piano filling in the background. Vocal timbre is excellent, avoiding any chestiness that can create muddy sounding lyrics. The bass line in “The National Anthem” is fast and clean. Cranking the volume produces a good punch without overwhelming the music. I’m used to a bit more low-end and wouldn’t mind a bit more low-end impact from the HDI-3600 and JBL has the HDI-3800 with 8” woofers for those that need more bass. The processed vocals are clear and enveloping. When the brass and sax enter, it’s common on many systems for the sound to get a bit muddled as there’s a lot going on. The HDI-3600 does an excellent job at balancing all the players. From the bass line to trombone, each part is able to stand on its own. From the chaos that is “The National Anthem”, I shift to “How to Disappear Completely”, a melodic atmospheric song. Thom’s voice along with
the accompanying instruments have a sense of dimension and space. I love the vocal clarity present here, it’s as if he is in the room. These speakers have great imaging! The JBL HDI-3600 is a satisfying way to take in some Radiohead.

“My Favorite Things” by John Coltrane is a lively, expressive experience on the JBL HDI-3600. The bass line is tight, quick and clean with zero bloat. It is a very natural low-end, allowing my mind to believe a real acoustic upright bass is creating the music. At first the hi-hat seems a tad too shimmery, but when closing my eyes, it takes little effort to imagine the percussive performance. With a very natural, full-range sound the JBL HDI-3600 is a great speaker for lovers of Jazz.

Chvrches, whose recordings can be on the brighter side of the sound spectrum, is not fatiguing through the JBL. If anything, I was looking for a bit more low-end extension and impact from a floorstanding speaker of this size and listeners who listen to more rock and bass-heavy music might lean towards the larger HDI-3800 but otherwise nothing except quality sonics.

The impassioned cello performance by Yo-Yo Ma in Memoirs of a Geisha is recreated quite well by the JBL’s. They are able to present a fairly stable image of the large stringed instrument.

Turning the volume way up on Melody Gardot’s “Once I was Loved” let’s her voice sing through the HDI-3600. Not a hint of sibilance, nor a touch of midrange chestiness can be heard. It is an absolutely lovely performance that I could listen to over and over!

Moving from side to side on my couch to try out different listening positions, the tonal quality of the HDI-3600 remained the same at each spot. As you would hope, the only thing affected were the location and volume level of each performer as I moved left to right. This speaks well of the design on the HDI horn. Clearly all the design and engineering that has gone into the HDI horn has paid off.

JBL HDI-3600 Speaker Conclusion

I didn’t know what to expect from the JBL HDI-3600 as my experience with horn speakers is next to none. All I knew was the stereotypical reaction that horn speakers are bright and harsh, and that they are only good at playing loud. The HDI-3600 completely changed my preconceptions. These speakers produce a beautiful, dynamic sound with excellent imaging. They are exceedingly respectful to the musicians they recreate before our ears, offering neutral tonality across different seating positions. Their only drawback might be with low frequency extension and output. Although the low-end is detailed and crisp, bassheads might want a bit more punch. I would look at either adding a subwoofer or giving the larger HDI-3800 a listen. In the end, I would be more than happy with a pair of these in my home and highly recommend giving them a listen.