Denon’s newly-released Heos line of wireless speakers are remarkably similar to those from Sonos — so much so that Sonos is suing Denon for patent infringement.

And Sonos is not the only one who thinks this way. We found the two products to be remarkably similar in a number of ways in a recent review comparing Sonos to Denon’s Heos line.

We weren’t the only ones who thought so.

Now Sonos is using these observations as part of its evidence that Denon has infringed on several of their patents.

In a blog post yesterday, Craig Shelburne, the co-founder & general counsel of Sonos, outlines the company’s beef with Denon and its parent company D&M Holdings. Chief among the complaints is that the Heos product possesses “many of the same elements found in Sonos products, with little or no effort to differentiate features or functionality.” Shelburne further claims that Denon’s devices “infringe at least four Sonos patents.”

Shelburne not only links to our review from his post, he also provides the full 258-page court filing, which goes into great detail regarding the ways in which Sonos feels that Denon has merely copied rather than innovated.

Can you tell the difference? Sonos website product listing sits above a similar layout for the HEOS by Denon site.

Above: Can you tell the difference? Sonos website product listing sits above a similar layout for the HEOS by Denon site.

Denon is hardly the first company to take a run at the wireless home hi-fi market that Sonos pioneered back in 2002 and continues to dominate today. Samsung, Bose, and LG have all brought new products to market that compete directly with Sonos. Yet none of them have created a line of products and accompanying marketing materials that so closely mirror what Sonos has created.

Sonos points out that even minor elements like Denon’s tag line for the Heos products is just too close to be seen as coincidental with their use of “Fill every room with music” coming within a few characters of Sonos’s tagline: “Fill your home with music.”

Another comparison presented in Sonos's legal claim against Denon.

Above: Another comparison presented in Sonos’s legal claim against Denon.

The filing goes on to discuss the four patents that are allegedly being infringed including: “Multi-Channel Pairing in a Media System,” “Method and Apparatus for Controlling Multimedia Players in a Multi-Zone system,” “Method and Apparatus for Adjusting Volume Levels in a Multi-Zone System,” and “Control Strip for Electronic Appliances.”

Of these patents, the first three relate to Sonos’s software IP (which you can see in the Sonos app for iOS and Android) and the last relates to their hardware IP, specifically the button+rocker design that appears on all Sonos audio hardware components. Visually speaking, it sure looks like Denon sought to borrow directly from this design.

The top panel of the HEOS 3 speaker (top) compared to the schematic in Sonos's patent for a Control Strip for Electronic Appliances (bottom).

Above: The top panel of the HEOS 3 speaker (top) compared to the schematic in Sonos’s patent for a Control Strip for Electronic Appliances (bottom).

Sonos claims that it isn’t interested in financial gain from this action and are instead using the lawsuit as a stick to bring D&M Holdings to the negotiation table in an attempt to work out a deal.

Will it work, and is Sonos really not interested in financial gain? Hard to say.

As of the publication of this article, Denon’s PR contact had not responded to our requests for comment.

Update: We’ve now heard from Denon’s representative Stacia Kirby, who told us by phone that Denon is aware of the lawsuit and is “taking it very seriously.” Kirby expects that Denon will have a formal comment ready “within 48 hours,” pending its review of the material.

Update October 30: Denon has formally responded to Sonos’s claims via email:

Mahwah, NJ  (October 30, 2014) – D+M Group, a global company dedicated to enhancing life through inspired sound solutions, today announced it will protect itself against a patent infringement complaint filed on October 21, 2014, by Sonos, Inc. in regards to D+M’s HEOS™ by Denon products.

 “D+M has been a technology innovator for over 100 years and has an extensive intellectual property portfolio to protect our products. Given our experience and wealth of expertise, we absolutely stand behind our HEOS products and technology and are well prepared to defend our intellectual property,” said Jim Caudill, CEO of D+M Group. “We are an innovative company, constantly seeking to create the best products in the marketplace.”

To meet the high bar set by Denon’s 100-year legacy of premier audio quality, Denon’s engineers and designers worked for more than ten years to develop HEOS by Denon.

Introduced in June, 2014, to date the HEOS by Denon product line includes three wireless multi-zone music players: HEOS 3, HEOS 5, and HEOS 7, a HEOS Amp, HEOS Link and HEOS Extend.  HEOS by Denon products are widely available in the marketplace. Denon dealers, distributors and customers will continue to be fully supported as Denon continues to innovate, invest and provide new products, features and functionality to its HEOS product line.  

Adds Caudill “We fully intend to take all necessary actions to protect our technology and product investment in our HEOS products.”