Published On: November 29, 2021

Hard Rockin' & Cohesive: JBL Synthesis HDI-1600 2-Way Bookshelf Speaker Review

Published On: November 29, 2021
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Hard Rockin' & Cohesive: JBL Synthesis HDI-1600 2-Way Bookshelf Speaker Review

JBL’s High-Definition Imaging speakers combine studio and consumer technology in an attractive package. Can the smallest speaker in JBL’s HDI lineup stay true and deliver the sonic goods?

Hard Rockin' & Cohesive: JBL Synthesis HDI-1600 2-Way Bookshelf Speaker Review

By Author: Brian Kahn

Brian Kahn is the longest tenured writer on staff at His specialties include everything from speakers to whole-home audio systems to high-end audiophile and home theater gear, as well as room acoustics. By day, Brian is a partner at a West Los Angeles law firm.

JBL’s High-Definition Imaging (“HDI”) series of speakers are part of the Synthesis line and combine traits from their studio monitors and more contemporary home speaker lineups. Those of you who are familiar with pro-gear have seen a ton of various JBL speakers with large horns above even larger woofers.

The recently reviewed JBL 4349 is a modern take on this classic studio design. While the HDI series uses a horn-loaded compression driver that looks like it may have come from a studio monitor, the HDI series pairs that driver with one or more mid-sized cones as is popular with many modern speakers. The question becomes, how well does this combination work in practice? 

The JBL Synthesis HDI Line

There are five speaker models in the HDI lineup, the HDI-1600 Bookshelf speaker ($1,800 per pair); HDI-3800 and HDI-3600 floor standing speakers ($5,000 and 3,800 per pair, respectively); HDI-4500 center-channel speaker ($1,750 per), and; the HDi-1200P subwoofer ($3,000, each). The cabinets feature clean lines with radiused corners and come in a variety of finish options including Grey Oak or Walnut wood veneers or high-gloss Black. JBL also makes a nice pair of stands for the HDI-1600 ($400 per pair).

The “HDI” in the name refers to the waveguide technology that is used throughout the series. I had the opportunity to speak with a few different JBL representatives while I was working on this article and received a ton of technical information. The series was designed under the watchful eye of Chief Engineer An Nguyen. The following is my attempt to provide a summary of the points that sounded particularly interesting but I invite you to check on the JBL website for more details if you are technologically inclined and want to learn more about Nguyen’s design and technologies utilized.

The horn-looking opening functions as a waveguide for the newly developed 2410H-2 high-frequency compression driver. The driver itself is a single voice coil, one-inch, ring-shaped driver made out of a polymer called Teonex. This new compression driver design applies JBL’s experience from the pro-audio world to provide benefit to the consumer side of the house. According to JBL, this includes approximately 20dB more headroom as compared to a more typical dome driver-based tweeter. In order to provide that type of headroom, the driver must be able to handle a lot of power, the 2410H-2 has a one-and-a-half-inch vented symmetrical pole piece. A Flux Stabilization Ring helps to block flux from the magnet impacting the voice coil which is said to help keep the lower frequencies clean and a copper shorting ring to reduce back EMF.

The waveguide portion of the assembly is derived from JBL’s famed M2 speaker system and provides approximately 100 degrees of horizontal dispersion and 80 degrees of vertical dispersion. The controlled dispersion patterns help smooth the transition to the cone driver (or drivers depending on the model) handling the lower frequencies.

In the case of the HDI-1600, the HDI driver assembly is paired with a single, six-and-a-half-inch, aluminum cone driver which handles everything below the 1.9kHz crossover point. I will not go into as much detail describing the mid-woofer driver as I did with the 2410H-2 but it is worth noting the anodized aluminum cone appears to benefit from some “trickle-down” technology from the Revel line with the anodization helping with damping. The underhung motor assembly provides up to one-inch excursion with a cast aluminum frame holding it all in place. The grille for the cone driver is secured with hidden magnets which allow for a clean, modern look.  

The HDI-1600 is fairly compact at 14.6 inches high, 9 inches wide and 11.4 inches deep and weighs in at just under a solid 22 pounds. The back panel has the port placed over dual, bi-wirable binding posts. The stated frequency response is 40Hz-30kHz (-6dB) and has a nominal impedance of 4 Ohms. What surprised me the most about the specifications was the relatively low sensitivity of 85 dB.  

JBL’s High-Definition Imaging speakers combine studio and consumer technology in an attractive package. Can the smallest speaker in JBL’s HDI lineup stay true and deliver the sonic goods? 35ba8969 image
Bi-wirable binding posts on the rear-ported HDI-1600

Setting Up The HDI-1600

The speakers are small and light enough for one person to set up. I placed them atop the JBL HDI-FS stands that secure to threaded inserts on the bottom of the speakers with four screws. I easily routed my Wireworld Eclipse 8 speaker cables through the wire management system, thereby further reducing any chance of someone catching a wire and knocking the speaker over. If I were keeping these permanently, I would have also taken advantage of the ability to fill the stands with sand or shot.

I started with the Naim Uniti Atom all-in-one music player sitting in between the HDI-1600’s, which were placed about seven feet apart. The combination of the Naim and HDI-1600 is a great minimalists' system. I later tried the NAD C338 which also allows for a single box of electronics but at a lower price point. I later tried the more powerful McIntosh MA6300. Thank you to Wireworld for providing all the signal cabling from their Eclipse Series 8 lineup which I found to be well made, neutral, and flexible enough not to be a problem with the stands. I will discuss these cables in more detail in a future review but they are deserving of mention here as well.

Lastly, I did some listening with pair of SVS SB2000 Pro subwoofers already set up in the room and later on the new SVS 3000 Micro subwoofer. Unless noted otherwise, all listening references below are sans subwoofer(s). 

How Do the HDI-1600’s Sound?

I started off with Shelby Lynne’ s “Just A Little Lovin’” (Qobuz, Hi-Res, Lost Highway Records). Lynne’s voice was portrayed realistically, with just a hint of sibilance. The JBLs also did a great job reproducing the detail of the bass guitar. The combination of accuracy and detail along with sharp imaging provided a realistic soundstage that I could almost reach out and touch. I thought the dynamics could be improved.

I tried the more powerful McIntosh integrated amplifier and a few seconds into the track there is a cymbal strike which was noticeably more dynamic and lifelike with the additional power. While the large horn-like openings in the baffle may make you think high-efficiency speaker, these speakers really benefit from a lot of power. As for the low-end energy, the HDI-1600s do a fine job into the mid 40 Hz range but there is only so much a 6 and a half inch driver can do in a small enclosure. There is a bass boost around 100 Hz which provides a subjectively stronger bass performance but may offend some purists.

Shelby Lynne - Just A Little Lovin' (WAV, DR14)

Sticking with bass for a moment, I pushed the limits of the speakers’ extension with Malia’s “Magnetic Lies”.  Malia’s vocals are in front of deep, powerful synthesized bass. As expected, HDI-1600’s did a great job with Malia’s voice, I cannot say how much of the rest was accurate or natural as it is mostly synthesized. The HDI-1600’s were able to reproduce all but the lowest synthesized low bass notes with the weight I have come to anticipate listening to this track through a variety of full-range speakers.

In any event, I was able to easily integrate a pair of SVS SB-2000 subwoofers which greatly extended the low-frequency extension. Recognizing the compact footprint of the system is greatly expanded when two subwoofers are added, I later tried a single SVS 3000 Micro subwoofer. The smaller drivers kept up with the detail but if you play a lot of music with deep, synthesized bass you may want to try the larger subs or perhaps the larger, floor-standing models from the HDI series.

Getting away from bass-heavy music, I played “Fast Car’ which had Tracy Chapman’s voice solidly positioned in between and slightly behind the HDI-1600s. Those of you familiar with this track will know how demanding it can be, and how good it can sound. The vocals and guitar were solidly positioned front and center on a plane even with the speakers. The bass and drums were also solidly placed on the soundstage a few feet past the speakers. The vocals and string reproduction were balanced and natural sounding.

I was expecting some noticeable discontinuity between the drivers but the transition was very smooth and hard to discern unless listening very carefully. The bass notes were detailed but a little light on weight, especially the drums. Adding in the pair of SVS SB-2000 subwoofers easily remedied this. I later tried the SVS 3000 Micro which also provided a noticeable low-frequency extension. Lastly, when I connected the McIntosh MA6300, I noticed a slight increase in bass definition at higher volumes. The HDI-1600’s do not need lots of power for low to moderate listening volumes but the extra power is beneficial at higher volumes.

Listening to “Bird on a Wire” from Jennifer Warnes’ album Famous Blue Raincoat (CD, Private Music). The JBL’s reproduced a similar soundstage as the B&W 600 Anniversary Series but the soundstage on the JBL’s extended slightly farther back with the speakers completely disappearing at the front plane of the soundstage. As before, the bass was tight but not particularly deep on kick drums. I found the JBL’s to be clear and detailed in the micro-dynamics while maintaining macro-dynamic capabilities so long as you provide sufficient power.

I found a high-resolution, 24 bit / 96 kHz version of Donald Fagen’s “Morph the Cat” from the album of the same name on Qobuz (Reprise, Qobuz). “Morph the Cat” had good dynamics with the NAD C338 (review coming soon) but was even better with the more powerful McIntosh, which had the added benefit of slightly better control in the bass region. Fagen’s voice was full-bodied, clear, and natural.

The cymbals and horns were clean on the high end while the bass guitar and drums were well defined. The reproduction of the horns was particularly impressive as the dynamics were accurately reproduced without any shrillness that many may associate with past horn speaker designs. The JBL’s rolled off cleanly at the low end, providing more bass extension than I anticipated for their size. I was grateful that I was able to play this track at high volumes without any apparent stress.

The Downside

The rear port design could be problematic in tight spaces, especially with the accompanying rear-ported center channel which is often placed in a cabinet. The speaker performs well, but has some limitations, the limited bass response is expected and I do not see that as a downside as the HDI-1600 maintains well-controlled bass performance down to its lower limit. However, this comes at the cost of reduced sensitivity. The HDI-1600s sound fine with lower-powered amplifiers but you need significant power to get their best performance.   

How Do The HDI-1600 Compare to the Competition?

There are several competing speaker lineups that provide similar options: Focal’s Chora line’ SVS Sound’s Prime Pinnacle line, B&W’s new 600 S2 Anniversary Series, and the Paradigm Premier line. I have only heard the Focal Chora (the stand-mounted 806) and B&W 607 S2. The JBL’s have significantly more bass response, both subjectively due to the 100 Hz bass boost and absolute extension but at the cost of size and efficiency.   

Final Thoughts

The JBL HDI-1600 is an outstanding mid-sized, stand-mounted speaker. I found it to be a well-balanced (other than the above-discussed bass boost), a cohesive speaker that, with ample power, can let loose and rock. The JBL remains composed at higher volumes but at very low listening levels there is a small loss of detail from the lower midrange downwards.

This JBL is unlike the two-way studio monitors of the past, there is no annoying discontinuity between the cone driver and compression driver. The transition can be heard upon close listening but the speaker had no problem portraying a cohesive image. The soundstage was slightly set back from the speakers and limited in overall size but with relatively well-defined images therein.

Harman’s more expensive Revel Be series may be slightly more nuanced and detailed, especially at lower volumes but the HDI-1600’s can disappear better than most speakers while rocking harder than their modest size would suggest.

  • Anonymous
    2021-12-11 10:30:29

    harman international these have the exact same finish as a pair of infinitys i bought in 1990.. vinyl oak wrap

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