Recently, Secrets contributor Sumit Chawla had a chance to interview HARMAN’s Senior Director of Global Engineering Nick Clarke on the release of the highly anticipated JBL Synthesis SDP-55 and SDR-35 AV processor and receiver.

JBL Synthesis SDP-55 & SDR-35

I hope that you have stayed safe and healthy through this pandemic. What has life at HARMAN been like during this time?

We’re very fortunate to be as busy as ever at HARMAN. While there was a massive period of adjustment for us and so many others, we have quickly found our feet and adapted to the current situation. Of course, there have been many challenges along the way and more I’m sure still to come, but the team has done a fantastic job in moving forward. We will continue to do what we do best, innovate, and bring new exciting products to the market!

With shelter-in-place instituted by many states and countries, the custom install market, which the Synthesis line caters to, was on pause. Have you started to see activity resume in this market segment?

I’m not sure it ever truly went away. At this level, installations are designed and specified a long time in advance and so while some projects have been paused due to safety considerations, we’re seeing very little in the way of cancellations.

Were there disruptions in the supply chain and facilities where your products are manufactured?

It would certainly be true to say that disruptions have occurred, but we have handled them accordingly and done our best to ensure it hasn’t impacted negatively on our customers. We are also incredibly fortunate to work with high-caliber partners, and they have done an excellent job of managing their own supply chain to minimize any further impact.

The announcement of the SDR-35 and the SDP-55 garnered a lot of attention at last year’s CEDIA. I don’t think folks expected to see a processor or a receiver at these price points in the Synthesis line. What has the feedback been from the dealers since the announcement, and now, the release of these products?

JBL Synthesis SDP-55

JBL Synthesis SDR-35

We have had extremely positive feedback from reviewers, distributors, and dealers alike, many of whom commented that these are the best sounding receivers they have heard. Our philosophy at HARMAN has always been to design and audition our AVRs like a stereo product, after all, we all know what a guitar should sound like!

Will these products be sold only as part of a complete Synthesis system?

No. While we created JBL Synthesis Certified Systems including these two products, we also expect these products to upgrade existing systems.

What differentiates the JBL Synthesis products from other home theater products on the market today?

JBL Synthesis draws on the very best of HARMAN engineering to create the most realistic listening experience possible, in a room of any size.

These two products, in particular, were the very first residential home cinema products to utilize DANTE audio connectivity, which has been a mainstay in the professional audio industry for years. We use the higher grade of ESS Sabre DAC and filter optimized for the devices, as well as Logic16 which is a proprietary up-mixing solution, allowing every speaker in the installation to play, even when listening to 2-channel recordings.

The SDR-35 and the SDP-55 are flexible and designed and engineered to work with all other JBL Synthesis products, including the new line of multichannel amplifiers

Both products offer DANTE (Digital Audio Network Through Ethernet), which is exciting to see. Please talk about this digital interface and the decision to include it.

JBL Synthesis SDP-55 & SDR-35 Back

We’re really excited to include DANTE on these two products. DANTE has become the de facto standard for audio-over-IP in the professional space thanks to its ability to offer uncompressed, multi-channel digital media networking with zero latency and perfect synchronization. Bringing that level of quality audio networking into the home is going to allow those working in the residential space to integrate audio across greater distances without the traditional – and costly – pain points. 

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Increasing channel counts in traditional audio integrations were adding to the spaghetti-like backs of equipment racks. Traditional cable runs resulted in increased cost and a limitation of how far you could practically run a wire. Those challenges are remedied with DANTE as you have the convenience of a single connection using the standardized infrastructure. 

With DANTE you simply connect the device to the network and you know it is going to work with every other device connected. That means fewer cable runs, easier install and setup, increased interoperability, and fewer constraints on the distance of integration.

Is there a fixed bit depth and sample rate used over DANTE or is it variable? If the latter, what is the negotiation protocol between the sender and receiver(s) over DANTE?

Due to the way DANTE operates, the sampling frequency is fixed when the link is established, although the bit depth can be variable.

Are there any implications with source content protected with HDCP?


Does the DSP have headroom that would allow for channel count expansion via DANTE down the road? In particular, I am curious whether a configuration such as 9.4.6 with DLBC might be possible.

Certainly, within an iteration of the AVR platform. However, the feedback we have from the majority of our dealers, and something you alluded to earlier on, is that 16 channels is the sweet spot.

The SDA-2200 and the SDA-7120 amplifiers, likely companions to the SDR-35 and SDP-55, also feature DANTE. Is the DAC section in these amplifiers the same as what is used in the SSP/receiver?

Essentially, yes.

How is volume control implemented when the amplifiers are connected via DANTE?

This is in the DSP of the AVR, as DANTE is simply an audio transport mechanism.

I am a big fan of using synthesized surround modes when listening to music. Logic 16 is making its way with these new offerings. Is the algorithm here based on Logic 7, which I liked for music, or is it a completely new algorithm?

While Logic7 was a fantastic algorithm, it wasn’t immediately scalable for the immersive world we enjoy today, so we created a new algorithm, though very much in the mold of Logic7. Our key aim was to provide a “lighter touch” so it was more an algorithm that you missed when it was taken away, rather than some other algorithms that provide you with an instant “wow” factor, but when you drill down you realize they aren’t doing much.

Can Logic 16 be used with content encoded with different flavors of Dolby and DTS codecs?

Yes, and as mentioned previously, the result of the “lighter touch” is to also ensure we retain any originally encoded directionality in the incoming stream, so sounds originally coming from the left won’t suddenly start coming from above you.

Are there separate modes for Music and Movies, and are there any customization options here?

Not currently, though this is something we are considering for the future!

You have released several firmware updates over the last few months. Development and testing were likely challenging in the last few months. Where do these products stand in terms of planned features and stability?

The last few months have allowed to us think about the future more than ever and what our customers need right now. Technology and the market are constantly advancing, and so too will our products. Throughout the life of the products, there will be continual updates and customers can be assured that they will be fully supported.

These updates will not only improve product stability but also add new features, such as the recent additions of DTS Virtual:X and IMAX Enhanced.

9.1.6 seems to be a sweet spot in the market right now, which is what the SDR-35 and SDP-55 are capable of. Is there a unified speaker layout that you recommend for the different immersive sound formats and up-mixers?

That’s a difficult question to answer – at that level, despite attempting to create standard layouts, every installation is slightly different. As part of the JBL Synthesis Certified programs, customers can be assured that their installer is giving them the best advice and experience possible in their individual case.

Is all DSP processing done at a fixed bit-depth and sampling rate or does it vary based on the channel count and Dirac being engaged/disengaged?

It does vary, but this is more due to the incoming audio. We plan to discuss this in an upcoming article in our Luxury Audio Group monthly newsletter, so watch this space for more:

What DSP are you using?

The flagship 1GHz TI DA10x device for zone 1 and dedicated DA8x for zone 2.

Harman has been a big advocate for using multiple subwoofers to achieve seat-to-seat consistency. Dirac is bringing their flavor of Sound Field Management (SFM) with the release of their Bass Control module. What has your impression been so far about this new offering from Dirac and how it compares with SFM?

Dirac Live Bass Control and SFM are very similar in their approach. Since we had already implemented Dirac Live, it was a more convenient setup experience to also enable Dirac Live Bass Control, rather than have another setup process, which was appropriate at these price points. SFM is still used in the JBL Synthesis Certified Elite Systems, where a higher level of installation is demanded by the end-customer.

Dirac allows one to customize the frequency range over which it operates. What are your thoughts towards using Room EQ over a limited range where the room dominates (below the Schroeder frequency) versus the entire audible range?

It’s very true that the “biggest bang for the buck” is the lower frequencies, but the fact is that we are always chasing diminishing returns in the systems. These small improvements cumulatively add up to significant differences, so we always advise equalization over the entire audible range.

Target curves are another important part of a RoomEQ system. You have curves available for download on your website. Can you please talk about the process that went into creating these target curves?

These target curves are developed as part of HARMAN’s wider research projects. Our research includes subjective and objective listening tests by trained and untrained listener groups in double-blind tests. These targets are proven to offer optimum sonic performance and can be deployed across all loudspeakers, with modified versions available for subwoofers and limited range loudspeakers.

How many Dirac filter banks are provisioned for?


Is Parametric EQ capability offered in addition to Dirac?


Anechoic EQ is a unique feature that you offer on the SDP-75. Can you please talk about this feature and whether this might get offered on this platform?

The SDP-75 is aimed at a different level of installation and, as such, as these even more advanced facilities. Currently, we have no plans to implement that on this platform, but that may well change as the platform evolves over time.

I would like to discuss measurements, which on the loudspeaker side, Harman has done considerable R&D to establish an objective analysis that correlates with subjective assessment. For components such as processors and amplifiers, has Harman undertaken any studies into audibility thresholds for various parameters that govern their performance … for example, jitter, SNR, THD+N, …?

Absolutely – within the AVR space, Arcam was one of the first to recognize and address the issue of jitter, so we have experience over several platforms specific to this area.

Do you see a difference in jitter levels between LPCM and compressed audio streams which are packetized and decoded on the DSP?

Not really, it’s normally the basic HDMI link that dominates the jitter due to the way any audio is transmitted over HDMI and the inherent jitter problems with the interface.

Virtual CEDIA just ended. The participation was limited, but the message coming out of it was that the custom install is healthy and consumer spending on home entertainment is on an uptick. What has your experience been across the different Harman Luxury Audio brands?

We have had a very busy couple of months and– we’re on track to meet our annual targets which is always a good thing, but it’s amazing when you consider those targets were set in September 2019, long before the pandemic! We launched two new products in the last few weeks and look forward to bringing further advancements to the market in 2021- watch this space!

The next big show, CES, is also virtual. Will Harman have a virtual presence at the show?

Absolutely, and it will be bigger and better than ever! As big as CES is, the virtual CES will offer us an opportunity to reach even more people and we have some really exciting plans that we can’t wait to share.

Are there any new features under development that you can talk about?

At HARMAN we never stand still, we are never complacent. Instead, we continue to push our designers and engineers to think outside of the proverbial box. At the moment we have several new product concepts in development for the home theater space and look forward to bringing them to the market soon.

Nick Clarke

As Senior Director of Global Engineering for HARMAN Luxury Audio, Nicholas Clarke is responsible for guiding premier engineering teams around the world to create award-winning products for HARMAN Luxury Audio’s renowned brands, such as JBL Synthesis, Arcam, Lexicon, Mark Levinson, and Revel.

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Before joining HARMAN in 2017, Clarke worked with Audiolab, which became TAG McLaren Audio, and became Chief Engineer there in 1998. After five years with TAG McLaren Audio, Nicholas was appointed Director of Engineering at International Audio Group. In 2006, Nicholas joined the A&R Cambridge team becoming Director of Engineering.

Following 11 years of driving innovation with A&R Cambridge, Nicholas stepped into a new leadership position with the HARMAN organization. His experience, knowledge, and passion for audio shines through high-performing, cutting-edge products such as the JBL Synthesis SDP-55 16-Channel Home Theater Processor and the JBL Synthesis SDR-35 16-Channel AVR featured in this article. He earned his degree in Electronics from Angela Ruskin University, Cambridge UK.