JBL Synthesis HDI Speaker Series Review

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JBL has been the choice of the world’s best musicians for over 50+ years ever since they powered Woodstock. In the country music world, playing a gig at the Grand Ole Opry is the holy grail of concerts. The engineering team at Ryman Auditorium, home to the Grand Ole Opry, decided to upgrade their almost 2 decades old JBL sound system. After extensive testing, they decided on a JBL Vertec system. They used an array of 10 of these per side for room-filling, accurate sound. While no one from Audio Advice has been lucky enough to hear this system yet, the reports are, it is just stunning.

You may ask what this has to do with a new line of JBL home theater speakers?

The answer my friends is trickle-down technology!

If you follow our videos and reviews, you know we love companies who allocate a large research and development budget to push the state of the art, then use what they learn on their "no holds barred" gear to make their more affordable products even better. The new HDI series from JBL uses a derivative of the compression tweeter drivers used in its over the top Vertec professional speakers. They also received the benefit of having access to all the incredible engineering and testing facilities available at JBL’s California factory.

We first heard the HDI speakers at the CEDIA trade show in the fall of 2019 and could not wait to get these into our stores. The HDI line up has 5 models aimed at high-performance home theater systems, two-channel music lovers, or if you are like most of us, a combination of the two! There are two floor-standing speakers, a bookshelf pair of speakers, a center channel, and a powered subwoofer. JBL has an optional set of very solid speaker stands the mount directly to the pair of bookshelf models.

At the time of writing this, the first few products are just trickling into the country. We were able to get our hands on the bookshelf and smaller towers to check out but thought it would also be fun to go over the technology all of the speakers share.

JBL HDI Speaker Series Lineup:

Shared Technology in the JBL HDI Series

Today’s fully immersive world of home theater is best experienced when all of the speakers sound as close as possible to each other. Heck, if you could use identical speakers all around the room, that would be the ultimate, but it’s pretty much totally impractical in a normal room. What you can do though, is assure the different speakers in a system sound are as close as possible to each other. JBL hit the ball out of the park in accomplishing this with the new HDI series. The patented 2410H-2 compression driver which trickled down from their professional Vertec series is identical in all of the speakers. It sits behind the patented HDI Waveguide, which is also identical for all of the speakers. You can not get any better than that for matching things. This technology gives you extremely consistent performance across a wide range, meaning everyone in your theater room will enjoy great sound, not just those seated in the sweet spot center seat. This same tech also provides a sense of great dynamics with never even the slightest trace of harshness found in some other compression type speakers. As a matter of fact, when we first fired up the bookshelf HDI, the thing that immediately struck us was how sweet it sounded!

HDI Bookshelf

We dug a little deeper to learn more about this new 2410H-2 driver and found some pretty interesting data. While you can’t really see how it is made without tearing apart the speaker, JBL sent us some tech data that shows a cutaway of it. It has a 1” voice coil which is pretty typical for a tweeter, but the diaphragm is like nothing we have ever seen. JBL calls it their Annular Teonex Ring Diaphragm. Most compression drivers look flat on the surface, but this new one looks like you are looking down on a rounded pyramid from the top. JBL claims this shape reduces break up and distortion with astounding dynamics. Whatever they did really works as the top end from this driver is very sweet and smooth.

As you move up from the bookshelf's to the top-of-the-line tower, the drivers used for the midrange and lower frequencies are different in size but have an identical build technology behind them. They all use an aluminum matrix cone material, which once again is trickle-down technology from some of the new higher-end JBL Synthesis in-wall speakers. This driver is supported by a cast aluminum frame and they all have a 1 ½” long-throw voice coil. The HDI-4500 center channel uses 4 of the 5 ¼” version of this driver, the HDI-1600 bookshelf uses a 6 ½” version in a two-way design, the HDI-3600 has three of them in a 2 ½ way design, and finally, the HDI-3800 uses 3 of the 8” version in its 2 ½ way design.

All of the cabinets are a ported design using JBL’s patented computer-optimized tuned flared ports. And speaking of the cabinets, they pass the “knuckle rap test”. We like to rap our knuckles on speaker cabinets to see how “dead” they are. If a manufacturer uses thick MDF enclosures with good bracing, even a ported speaker will feel pretty dead to your knuckles when you rap on the top and sides. JBL uses .75” MDF with lots of internal bracing which results in a very inert feeling cabinet. Another way to make a cabinet have less resonance, although it costs more, is to make it less of a rectangle with curves. JBL applies this as well to the main speakers in the HDI line up. This very inert and resonance-free cabinet design lets the speaker drivers do their job without adding any coloration of their own to the sound.

HDI Port

All of the 4 speakers have magnetic grills, although we kinda like the look of them naked ourselves. The cool-looking compression waveguide with the curved cabinet looks great in our opinion, especially in the Gray Oak finish. You can get the HDI series in an automotive high gloss black or furniture grade Walnut or Gray Oak veneers. The two towers and bookshelf all have a gloss black base on the bottom. The towers come with rubber feet to protect hardwood floors but do include spikes for carpet. The bookshelf has the same type of base with holes for attaching it very firmly to its custom speaker stand ($400/pr for the stand). The stand comes with spikes on the bottom with four small rods that anchor the speaker to the stand, a pretty cool design.

With identical high-frequency compression drivers and woofers made of the exact same construction, the HDI series is designed to enable you to set up a very well matched 5.1 home theater system. We do have one little nitpick though. JBL needs to release some matching in-wall and in-ceiling speakers to complete the whole package for people who want a full-blown Dolby Atmos system. The Revel architectural speakers will likely be a decent match as they are designed in the same facility to the same neutral standards, but we would love to see a version of this great compression driver in an in-wall and in-ceiling product, hint hint, JBL!

The final piece of the HDI line up is their new 12” powered subwoofer. This one gets a cone similar to those used in their high-end professional woofers, a Poly-Plas cone material. Like the other woofers, it has a cast aluminum frame with a huge 3” long-throw voice coil. When we looked at a picture of it, the driver is massive with a huge magnet structure. The subwoofer amp gives you both balanced and RCA inputs with the ability to set crossover levels, gain, and phase. Those are all pretty standard features but it also adds one thing most subs could use, but we rarely see. Every room is normally going to have one pretty narrow region in the bass output where there will be a big peak. If you can find the frequency and width of this peak, you can knock it down with a parametric equalizer, which lets you dial in a dip exactly where that peak is. A parametric type EQ will let you specify the exact frequency along with the amount of correction on each side of the frequency. The new HDI sub has this feature, which is pretty neat. As we write this, we have not received a sub yet, but our contacts at JBL say this is one of the best sounding subwoofers they have ever produced. That is no surprise as it is $3000 and has all of their latest tech in it. They also told us it was able to put out so much low-frequency energy no one was able to stay in the room whey they tested the protection circuitry designed to shut it down if it gets pushed too hard.

HDI Tower

Performance

We first set up the HDI 1600’s in our McIntosh room connected up to their C49 preamp and MC152 solid-state power amp. Our source for this listening session was the McIntosh MT-5 turntable and a Sonos Connect going digitally into the great DAC inside the C49. We had some other bookshelf speakers sitting on some very solid stands so we used those stands for the HDI 1600s.

When the stylus hit the record on the classic Girl from Ipanema cut, our first reaction was how smooth and sweet the sound was! We sat down and felt the image was off a bit but then discovered someone had messed around with the balance control on the C49 and after that was fixed we had a big rock solid center image and we just let the entire song play. **After a couple of more vinyl cuts we were convinced this was one special speaker, but wanted to try some Tidal streaming on different varieties of music. **

Every once in awhile a speaker comes along that just seems to get everything right. We were starting to think this about the HDI 1600. Dynamics, check, soundstage, check, great transitions between the speaker drivers, check! Finally, we decided to play some challenging music from a bass drum perspective. While these little guys can in no way produce the full impact of a bass drum, in the area they cover, things sound super accurate from a timbre standpoint with just tons of details. They also never sound like they are trying to “fake” a deeper low end than they really have with a bass bump at 80hz like we’ve heard sometimes from other small speakers. The bass they produce is just outstanding! At $1600 a pair for these, they are one heck of a special speaker. We actually felt like they sounded like a mini version of one of our JBL favorites, the 4367, which is JBL’s top of the line professional two-way speaker checking in at $15,000 a pair.

We did notice the meters on the McIntosh amp were being pretty active even though the speaker never ever sounded strained so we checked the efficiency spec. Most JBL speakers are 90+ dB in efficiency, but these guys are 85db, which does mean you will need a pretty good amp or receiver to get them going. While they should run just fine on a modestly priced receiver, one with a good power supply should really make them come to life.

Next up were the HDI 3600’s for our testing. These guys are much more efficient and should be able to work well with even a lower power tube amp. We tried a lot of the same cuts on the HDI 3600s and found them to be pretty similar in presentation as the HDI 1600s. With the larger cabinet, you do get far more deep bass and their increased efficiency gives them even more dynamics. We pulled up the classic Yes piece, “Owner of a Lonely Heart”. It takes a speaker that is super phase accurate to show off how Yes manipulated the phase on this cut to give it a huge sound that goes way outside the speakers. The HDI 3600s passed the test with flying colors! Its also just a fun track to listen to on a speaker like the HDI 3600 and we wound up rocking out to the whole cut! Like the 1600s, the 3600s are a ton of fun to listen to. We can not wait to get our ears on the top of the line HDI 3800s!

With just the two models in so far to test, we were not able at this time to do a full home theater check out. However, we suspect the center channel will be incredible at revealing low-level details that draw you into the movie. We have also found if a speaker sounds great on music AND is dynamic and involving, it will also be a great home theater speaker. So we suspect, this will be an amazing home theater system when we get them all in.

Test Tracks

One of our favorite demo tracks of all time is from the album Getz/Gilberto featuring Stan Getz and Joan Gilberto. This classic bossa nova album was recorded in March of 1964. The most famous track is called “The Girl from Ipanema” features the male voice of Joan Gilberto and the female voice of his wife, Astrud. This is a track that’s all about the music flowing in front of you. A great system will show off the smooth and effortless sound of Joan Gilberto’s rich voice, and if the system is good, it’ll allow you to hear into the subtle emotions as Joan plays off the background guitar and upright bass in the beginning. At about 2 ½ minutes into the song, Stan Getz comes in with his smokey tenor sax that will sound like it's right in front of you if the system is capable of properly reproducing it. To experience this recording to the full extent, it takes an audio system capable of producing great dynamics that allows all of the subtle details to shine through... But wow, when everything aligns, you can play this cut over and over and understand why even after 50+ years it's still one of the best jazz recordings of all time. When we played this recording for the first time on the HDI 1600’s with the McIntosh stack, we were amazed by the amount of detail we remembered experiencing from listening to this track originally, and how easily it was all revealed.

Another track we used when testing the JBL HDI series is from the 1983 90125 Yes album. The first track is “Owner of a Lonely Heart.” While this is not one of the best sounding recordings out there, it is a great one for telling you if your speaker positioning is spot on and if your system is phase accurate or not. A trick used by many engineers to make the sound seem like it's coming from outside the speakers is to play around with the phase of the recording. This is really apparent on this Yes cut. On the HDI 3600’s, the sounds were far outside the left and right speakers. As the cut progresses, it has a classic rock beat which makes you want to tap your toes to the music, especially if your speaker can show off the dynamic contrasts. We had a great time listening to this on the HDI 3600’s even though it's not that outstanding of a recording from an audiophile perspective. But, in our opinion, that’s what makes a truly great system, and one that’s fun to listen to even if the recording is not an A+.

Recommendations

We are very excited about this new line of speakers from JBL that can give you a lot of the performance found in their much more expensive speakers. These are not inexpensive, entry-level speakers by any means, but they connect you to the music in such a way that ups the ante on listening and we are sure they will give us goosebumps when we put together a complete home theater package with them. We would recommend you give them some good power to bring out their best (true for any good speaker). A receiver from Arcam, Lexicon, Anthem or some of the bigger models from the larger companies would do a great job. We have a feeling the HDI series is going to be an Audio Advice favorite for years to come!