JBL Synthesis SDR-35 review | What Hi-Fi?
When hunting for AV receiver or amplifier, it can be difficult not to get carried away in the battle of specifications. As a component to which everyone else is connected, these are essentially the brains and the beating heart of a system (not to mention the most expensive single element), so it is understandable that a certain amount of specification craze creeps in. Even features you don’t like you don’t need now may become important in the future and you’ll want to cover as many bases as possible.
Those who become too focused on comparing specifications may miss the JBL Synthesis SDR-35. Although format support is in-depth, its enhancement for only seven channels and the (current) lack of HDMI 2.1 the connections are crossed by Denon receivers, which cost about one-sixth of the huge price.
Of course, what the spec sheet can never tell you is how a product sounds, and in that respect the JBL Synthesis SDR-35 is clear above any other AV amplifier we’ve tested in the last few years.
JBL Synthesis SDR-35 is based on Arcam AVR30, although with a number of improvements. The biggest of them in terms of sound quality is said to be the transition from the DAC of the ESS Saber 9026 Pro to 9028 Pro. This is said to lead to lower distortion and better detail and dynamics.
Technical specifications JBL Synthesis SDR-35
HDMI inputs x7
HDMI outputs x3 (including eARC)
HDMI 2.1 No
Power 100W (per channel) in 8 ohms with 7 driven channels
HDR formats HDR10 +, HDR10, HLG, Dolby Vision
Audio formats Dolby Atmos, Atmos Height Virtualization, DTS: X, DTS Virtual: X, Auro 3D, IMAX Enhanced
Connectivity Chromecast, AirPlay 2, aptX HD Bluetooth, Roon Ready
JBL and Arcam both use Dirac Live Room Correction (a more engaged and sophisticated approach to calibrating microphones on most modern AVRs), but only JBL comes with Dirac’s bass control feature, which uses machine learning and AI for more -accurate and balanced bass transmission around the listening space – something that should be especially useful if your system includes multiple subwoofers. Anyone buying an Arcam AVR30 will have to pay an extra £ 252 to add this feature.
The SDR-35 also features Logic 16 processing, which is designed to create a more compelling 3D sound landscape. All signals, even those in mono, can be mixed up to 15.1 using Logic 16.
Last on the AVR30’s list of upgrades is the inclusion of Dante, which allows lossless transmission of high-definition AV signals over standard Ethernet cables. If you have a system installed in your house, you (or your custom installer) may be grateful. It should also reduce wiring costs.
The JBL Synthesis SDR-35 shares many specifications with its Arcam cousin, including the Class G amplifier, which consists of two power supplies – one high-efficiency power supply that handles low-volume effects, and another with more power that it absorbs when higher volumes are needed.
The device is designed to provide enough energy as needed, while ensuring that no more energy is used than necessary. The intersection between the two power supplies is designed not to be heard.
Power is calculated at 100W to 8 ohms when all seven channels are powered, and this is really the maximum that the SDR-35 can control when used alone. Although it can decode and process up to 15.1 channels in a maximum configuration of 9.1.6, taking advantage of this requires the use of additional amplification.
The obvious choice here is the JBL Synthesis SDA-7120 seven-channel amplifier. Used alone, it’s best to think of the SDR-35 as a 5.1 amp with two additional channels that can be used to add backs, heights or a second stereo zone.
There is a significant selection of physical connections on the back of the SDR-35, including six analog RCAs, four coaxials and three opticals (there is also a 3.5mm aux input on the front panel). The HDMI tab consists of seven inputs and three outputs, one of which is supported eARC.
However, this is the only nod to the HDMI 2.1 functionality, and all sockets are with 18 gbps HDMI 2.0. By the end of 2021, a hardware upgrade to HDMI 2.1 will be offered, but this will include returning the device to a dealer and paying as yet unknown additional costs.
Although the lack of HDMI 2.1 functionality can be alarming, at the moment this is a problem only for hardcore gamers. JBL now supports 4K signals at up to 60 frames per second, which currently no film source exceeds, and format support is exemplary, with HDR10, HLG,, Dolby Vision and HDR10 + all supported by video, and Dolby Atmos,, DTS: X, Auro 3D and even IMAX Enhanced for audio.
Dolby Height Virtualization and DTS Virtual: X are also on board for those who want to simulate altitude effects without the use of a physical ceiling or speakers.
There are many ways to wirelessly transmit your content to the SDR-35, including aptX HD Bluetooth,, Apple AirPlay 2 and Google Chromecast. It also works with the Harman’s MusicLife app, which allows streaming music from the like Tide,, Deezer and Qobuz, plus records stored on your own network.
MusicLife also takes care of podcasts and internet radio, and the SDR-35 has built-in FM and DAB tuners if you want to get your radio the old-fashioned way. Finally, it is too Run Ready.
The JBL Synthesis SDR-35 looks significantly different from its Arcam connection, as the traditional gray finish of the latest and slightly dated style has been replaced by a more monolithic design, finished in an elegant matte black color. Eight small buttons on the front allow you to switch inputs and navigate menus, and there is a large and tactile volume button. Next to the aforementioned 3.5 mm aux-in there is a 3.5 mm headphone jack.
The glossy black bar on the front of the device houses a full-color OLED screen that boldly displays the current input, format, and volume, and can also be used to access the receiver’s menus. The text for the latter appears in a small font, so navigating the menus and changing options from across the room is not actually feasible. While the menu options are displayed on the connected TV or projector, the whole menu system is not and this makes navigation more difficult and thus.
The SDR-35 is a large device, measuring 17 cm in height and 43 cm wide. You will need a large, well-ventilated stand, especially if you plan to add an amplifier or amplifiers.
In all likelihood, anyone who buys the JBL Synthesis SDR-35 will also do the installation and setup for them, and it’s worth it. Not that the receiver is significantly more complex than other products of this type – in fact, in many ways it is refreshingly clear – but to make the most of the Dirac Live Room correction takes a lot of knowledge and patience.
In our home theater test room, calibration actually weakens the delivery, but the results in your room can be more effective, especially with a professional installer involved. Either way, switching between your Dirac preset (or presets) and standard mode is at the touch of a button, so it’s easy and quick to compare and contrast.
In our manually calibrated configuration 7.1, the JBL Synthesis SDR-35 sings. As Deadpool makes his piece of the camera at the beginning of the highway shootout scene in his first film, we are immediately struck by the purity and clarity of delivery. There is a beautiful naturalism in Ryan Reynolds’ voice – richness and weight, which makes less first-class AV amplifiers sound a little dirty and insignificant. In multi-character scenes, each voice has a clearly defined and unique timbre. Until you hear a product that is sorted as well as the SDR-35, you don’t realize how inaccurate others are in this regard.
In quieter scenes, JBL turns out to be a nuanced and fine performer, digging out the finest details and deftly defining low-level dynamic changes, but it’s also real power when the action requires it. As the bullets begin to fly, there is an extremely satisfactory dynamic shift and a huge increase in total weight and weight. The leading edges of the effects are clearly defined, but there is nothing of the aggressiveness that more affordable amplifiers are mistaken for. Instead, this hit is huge, rich and solid. Satisfies in a way that few home theater products can be.
The delivery is cohesive, both in terms of tonality and in terms of organization. No frequency stands out illegally and the effects are transmitted from one speaker to another without the listener’s attention ever being drawn into the process. You are simply drawn and immersed in the film you are watching, which is exactly as it should be.
JBL gives strong arguments for the musical powers of the SDR-35 and this is justified. He plays Michael Jackson That’s it Blu-ray, has unsurpassed rhythmic and spatial accuracy of presentation. Each instrument and vocals are clearly defined and given a lot of space in the surround field, creating an impressive feeling of presence in the concert hall for rehearsals. The levels of detail, dynamics and timing are also excellent, conveniently conveying the incredible quality of Jackson’s live band.
JBL is also a music artist with stereo sources. You don’t have to spend thousands on a stereo amplifier that sounds even better, but the SDR-35 is very accomplished for an AV amplifier by providing SBTRKT Trials of the past with great urgency and impact, Møl’s opening Fog with a charming sense of space and growing threat, and to Nick Cave and Warren Ellis The road with layers of texture at a low level of dynamic finesse. That’s about as much hi-fi as home theater products.
JBL Synthesis SDR-35 is an extremely good home theater receiver. Its specs may be a bit lacking in terms of amplified channels and lack of HDMI 2.1 compared to more popular AV amplifiers like Denon, but in terms of sound quality it is in a completely different league, delivering music and movies with really rare maturity and sophistication.
The Arcam AVR30 may still turn out to be a better performance per pound to buy, and we hope to find out soon. However, this JBL is stunning in itself, and if we build a high-end home theater from scratch, it will be the first component in the short list.
Read our guide to the best AV receivers
Read ours Review of the Denon AVC-X6700H