JBL Synthesis SDR-35 AV Receiver Review

Posted on 3rd March, 2021

JBL Synthesis SDR-35 AV Receiver Review

Tony O'Brien samples one of the finest AV receivers he's ever had the pleasure of reviewing…

JBL Synthesis

SDR-35 AV Receiver

AUD $14,999 RRP

James B Lansing began producing loudspeakers in 1946, and the rest, as they say, is history. JBL is now ubiquitous in pro audio and commercial cinema, with a list of credits that include early cinema speakers and Woodstock. Much of this has been under the guiding hand of Harman International, which acquired JBL in 1969. It has a portfolio of products that include Infinity, Lexicon, Mark Levinson, Revel, and Arcam.

Harman is also responsible for creating a wealth of research surrounding loudspeakers and room acoustics; its research on the use of multiple subwoofers has become the industry standard. JBL is one of the more interesting companies found within its luxury product portfolio. Unlike other brands, JBL plays in several spaces, that distinctive badge equally likely to appear on an entry-level set of speakers as it is on some of the finest speakers and electronics that money can buy. Indeed its luxury Synthesis range incorporates speakers, processors, amplifiers and more recently, the company's first AVR receiver – the high-end SDR-35 that you see here. 

A sixteen channel-capable surround sound solution with seven channels of amplification as standard, this does an awful lot. You'll need external amps to achieve the full number of channels, and for this JBL recommends either the Synthesis SDA-7120 seven-channel and SDA-2200 two-channel amplifiers.


In its purest form then, the SDR-35 is a seven-channel AV receiver – albeit an expensive one. JBL representative Nick Clarke says that as prices go down and channel counts increase, sacrifices are made to the audio section and – in particular – the power amplification. His company believes that this is the wrong approach for high-end; seven channels are believed to be the optimum number, with the flexibility to add more with external amplification. 

The JBL's Class G amplification is rated at a healthy 100W RMS watts per channel (7 channels driven, 1kHz, 0.2% THD, 8 ohm). The system is a stalwart of Arcam's higher-end products and – given Harman's relatively recent acquisition of Arcam – unsurprisingly mirrors the power amplifier section of that company's well respected AVR30 design. Class G lets amplifiers run in Class A – where the output devices are powered up all the time, and there's no switching distortion – at normal listening levels. Then, when called upon to deliver transient peaks, it calls for backup and switches into Class B mode, boosted by additional power supplies. It's more challenging to implement than Class AB, but Class G topology is more efficient and capable of driving complex speakers.

The SDR-35 supports Dirac Live 3.0, with up to sixteen channels of digital room correction and Dirac Live Bass Control. With a single subwoofer, Bass control is said to provide smoother bass reproduction in the often difficult to take crossover area. Used with multiple subwoofers, Bass Control will correct for bass gaps and provide more accurate low-end reproduction in the listening area. 

Naturally, the SDR-35 supports a bevy of surround sound solutions, capable of decoding the latest surround codecs from Dolby, DTS, Auro, Imax Enhanced and Harman's own Logic 16 upmixer. The notable absentee from its list of audio codes is DTS:X Pro, which is still in development. 

Another welcome inclusion is Dante, which allows all sixteen channels of processed audio (or eighteen if you include Zone 2) to be routed to other Dante enabled devices over a standard network, with claimed near-zero latency and synchronisation, eliminating the need for analogue audio cables between the SDR-35 and amplifiers. I should point out that at the time of this review, Dante is not stable and not recommended for end-user use. Fortunately, firmware upgrades seem to be released every 4-6 weeks, and each one brings a long list of bug fixes.

Pundits are going notice more than a few similarities between the big JBL and Arcam's AVR-30, the notable differences being Logic 16, Dante and Dirac bass management which is an optional add-on with the AVR-30. JBL's Nick Clarke says that while there are many similarities, they're in areas that are difficult to provide any differentiation, such as HDMI switching. He points out the SDR-35 uses a much higher grade ESS Sabre DAC than the Arcam, for example. The JBL supports Dolby Vision, HDR10+, and 3D via its HDMI 2.0b (HDCP 2.2) inputs on the video front. Network streaming is available with Apple Airplay 2, Harman's Luxury MusicLife app Chromecast and Bluetooth with aptX HD.

While Roon capability is advertised, at the time of this review, JBL says they currently have a “number of products going through the certification process”, so our best guess is it will be activated in a future firmware update.


The SDR-35 features a sleek minimalistic design that's rapidly becoming commonplace. Finished in matt black offset by a gloss black glass display and large volume dial, it's a striking piece of machinery. Front and centre are ten small buttons, which provide a means to navigate the SDR-35's menus, manually select surround modes, zones and power the unit. Despite both the numerous controls and headphones and auxiliary inputs, the front panel looks surprisingly uncluttered.

Measuring 433x171x425mm, it's going to slide comfortably into most AV racks, and its 10.6kg weight is a very easy load – that's Class G for you. Although the SDR-35 essentially shares the same chassis as the AVR-30, aesthetically, it's an entirely different looking AVR, at least from the outside. At the back, you'll find fourteen gold plated speaker binding posts placed vertically on top of one another. Connection options will accommodate all but the most esoteric systems, with seven HDMI 2.0b (HDCP 2.2) inputs and three HDMI outputs, with eARC.

Preamplifier inputs are available for all sixteen channels, with three TOSLINK optical and four coaxial digital inputs. The SDR-35 also features dual IR inputs and 12-volt triggers, an Ethernet port, USB socket, FM/DAB aerial socket, RS 232, power inlet, voltage select and three rabbit ears for wireless networking and Bluetooth. The dual subwoofer outputs can be expanded to four by connecting subwoofers to channel 13 and 14. JBL recommends this method for connecting two subwoofers as well, as this provides – unlike the main sub outputs – individual gain and distance settings.


Both build and styling are excellent, the SDR-35 wearing its high-end pedigree proudly. The unboxing experience feels more like an afterthought, however. I know this is nitpicking, but at this price, people need to be wowed! The box includes a remote calibration microphone, batteries, power cord, welcome letter and a hefty user manual. The remote is finished in matt black and accentuated with white and blue buttons, which must be pressed to activate the backlight. Save for the JBL Synthesis logo, it's identical to Arcam's AVR-30 remote. While the SDR-35's main display looks to all intents and purposes like a touchscreen, unfortunately, that's not the case. It lacks an onscreen display, and as informative as the display is, it's tiny, so you'll either have to have 20-20 vision or get up close.

JBL either assumes a certain amount of knowledge on the user's part in setting up the SDR-35 or expects that a dealer will be installing the unit. Despite the lack of hand-holding, there's nothing too daunting in the set up, and experienced users will be able to do so with relative ease - if not, then the manual is at hand. The menus can also be accessed via a web GUI which makes setting up a breeze for experienced users; I even found myself making on-the-fly changes on the GUI from my smartphone.

Although a powerful tool, Dirac does come with a steep learning curve – especially if you're used to more automated systems like Audyssey. There's also an app-based setup procedure for Dirac, but I recommend using a PC and the supplied microphone rather than relying on your smartphone's mic. It's undoubtedly one of those cases of nothing ventured, nothing gained, as Dirac is one of the most powerful but flexible room EQ systems available. It needs to be downloaded to a laptop, with the included microphone – or another such as miniDSP's UMIK-1 – connected to the computer via USB.

After locating the SDR-35, Dirac activates the full version, which covers the entire frequency spectrum, in addition to bass control. With the calibration completed, it then applies the software's default curve, although other target curves can be downloaded from Harman. The default curve is very much to my liking. In addition to choosing which curve to apply, speakers can be grouped to match one another's corrected frequency response more closely, and you can specify the range in which EQ is applied. While bass management does a lot of its work behind the scenes, tinkerers will be delighted by the option to choose different crossovers and see the predicated response. 

The SDR-35 can store up to three Dirac calibrations selected via the onscreen display or remote. Therefore, owners can apply different calibrations to sources and, of course, experiment with different curves and evaluate them against one another.

For my review purposes, the SDR-35 was connected to VAF Signature i91 front and centre speakers, four VAF i90s were used as rear surround and ceiling mounted Atmos speakers. Channels 13 and 14 were connected to twin custom Veritas 10” subs creating a 5.2.2 Atmos layout. Video sources consisted of Panasonic UB9000 and Sony UBP-X700 4K Blu-ray players and Apple TV, connected directly to a Lumagen Radiance Pro; a Sony VPL-VW270ES projected images onto a Severtson 100” Cinegray 16.9 screen.


The SDR-35 creates a massive, airy, open sound field – one that combines with excellent channel steering and imaging to drop the listener right in the middle of the action. Sonic detail is delivered in abundance, conveying all the subtleties of soundtracks and an excellent sense of placement in the sound field. The big JBL was equally at home playing at low volume levels as it was at higher ones. Its G-Class amplifiers proved not only powerful but lightning-fast, able to swing serious amounts of power in a heartbeat whilst retaining a great sense of poise. Bass was powerful yet instant and blended seamlessly with the main loudspeakers.

For example, as the Supermarine Spitfires make their debut in Christopher Nolan's Dunkirk, the SDR-35 created an enormously airy sound field. The front soundstage revealed not only a sense of height but a tremendous amount of width, wrapping the viewer in sound. Objects had a tangible sense of weight, regardless of where they were located in the listening room, and none of the speakers were overlooked. The roar of those Merlin engines was carried with a sense of weight and authenticity that most AVRs don't even come close to.

The SDR-35 also turned in a wonderfully detailed performance with the 5.1 PCM soundtrack of The Secret Garden. It proved a superbly articulate machine, as many AVRs can render this detail but cannot quite locate it within the sound field. With the JBL however, the barking of a dog in the distance was placed clearly where it should have been in space. Tasked with Julien Leclercq's The Bouncer in the wee small hours of the morning, I had no trouble making out dialogue at low volumes. Despite the low levels, the SDR-35 retained all the traits I had come to expect, never leaving me feeling like I was listening to hushed multichannel stereo.

With a quiet afternoon on my hands and the SDR-35 turned up to eleven – if you pardon the Spinal Tap reference – the big JBL Synthesis AVR did an outstanding job on the Book of Eli DTS-HD soundtrack. Even with volume levels that bordered on uncomfortable, the SDR-35's power amps retained all their poise and dignity, seemingly without limit in my small home theatre. As Eli and Solara faced-off against Carnegie's henchmen, gunshots were delivered with tremendous force and slam. Bass was smooth and seamlessly blended with the main speakers, yet incredibly powerful. As a bazooka slammed its way into the derelict home they were defending, I was left reeling.

Imaging is equally impressive, the SDR-35 deftly placing effects wherever it chose to with the 4K Blu-ray of Man of Steel, seemingly oblivious to the speaker layout. Here I found myself looking overhead for a non-existent height channel over the listening position. Of course, it's no substitute for adding extra height or surround channels, but it did a superb job of helping fill the gaps in my 5.2.2 system. Not typically a fan of up-mixers for stereo soundtracks, I found myself increasingly using Auro 2D for streaming titles devoid of a surround mix. It won't perform miracles but does an admirable with legacy mixes.


Used as a sixteen channel surround sound solution, the JBL Synthesis SDR-35 provides a great value proposition – even with the cost of extra amplification factored in. Used as a seven-channel AV receiver, it's tempting to write the SDR-35 off as an extravagance. However, if you're in a position to consider it, I'd strongly encourage you to arrange an audition.

Power, bass, detail and imaging are the key traits that define this product. Whereas many such designs possess these to varying degrees, the SDR-35 not only shines in these areas but brings them together as a cohesive whole in a way that others simply cannot. This done, it creates a surround sound listening experience that's unmistakably high-end, immersive and believable.

Ironically, the SDR-35's natural rival is Harman's own Arcam AVR-30 stablemate. While the SDR-35 bettered the AVR-30, it was a tight race. The better DAC and Dirac Bass Control's inclusion give it a small edge over the AVR-30. As it stands, though, the JBL Synthesis SDR-35 is the finest AV receiver I've had through my home theatre, setting a new benchmark in terms of performance.

For more information visit JBL Synthesis


    Tony O'Brien's avatar

    Tony O'Brien

    As the owner of Adelaide based ‘Clarity Audio & Video Calibration’, Tony is a certified ISF Calibrator. Tony is an accomplished Audio-Visual reviewer specialising in theatre and visual products.

    Posted in:Home Theatre Amplifiers AV Receivers & Processors Applause Awards 2021
    Tags: jbl  convoy 

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