The embers of a long-burning patent war between Google and Sonos were stoked anew Wednesday when the Federal Circuit upheld a Patent Trial and Appeal Board (PTAB) ruling, knocking out key claims in a Sonos patent and handing Google a procedural triumph in the tangled battlefield of high-tech intellectual property.

A three-judge panel of the U.S. Court of Appeals for the Federal Circuit ruled that 22 claims in Sonos’s U.S. Patent No. 9,967,615 were "obvious" and unpatentable, affirming the PTAB’s invalidation of the music playback patent — one that Sonos had hoped would bolster its arsenal in a broader war against Google over smart speaker technology.

Judges Unimpressed by Sonos’ Challenge

In its appeal, Sonos argued that the PTAB had erred in finding prior art combinations would motivate a skilled artisan to replicate its patented technology. But Judges Sharon Prost, Richard Linn, and Kara Farnandez Stoll disagreed, siding with the board’s logic and Google’s interpretation.

The opinion was nonprecedential, meaning it won’t carry binding legal weight in other cases, but it delivered a strategic blow nonetheless. Sonos had counted on the ‘615 patent to anchor several claims in a sweeping IP conflict centered on the explosive growth of Google's Chromecast Audio, Nest, Pixel, and Google Home products.

A Fragmented Legal Saga Unfolds

The decision is only the latest skirmish in a multi-front legal war that began in 2020, when Sonos sued Google, accusing the tech giant of stealing core innovations originally developed under a partnership. A $32.5 million jury win for Sonos was later tossed out by U.S. District Judge William Alsup, who criticized the patent prosecution process as legally defective and “sad.”

That case is now awaiting oral arguments at the Federal Circuit in July, and could potentially reshape the landscape once again.

Trade Commission, Other Courts Also in Play

Meanwhile, the U.S. International Trade Commission (ITC) in April closed another investigation into whether Sonos products infringe on Google’s patents — this time siding with Sonos after finding Google's asserted patents invalid.

On a separate front, Judge Edward M. Chen of the Northern District of California granted summary judgment for Sonos in a Google-initiated suit, invalidating the last of five patents originally asserted by Google. That ruling is also under appeal, adding yet another twist to this ongoing IP chess match.

Counsel and Courtroom Heavyweights

Representing Sonos in the current appeal are attorneys from Orrick Herrington & Sutcliffe LLP and Lee Sullivan Shea & Smith LLP, including Jonas Q. Wang, Eric Shumsky, and George I. Lee.

Google is backed by a formidable legal team from Finnegan Henderson Farabow Garrett & Dunner LLP, led by Cory C. Bell, Erika H. Arner, and others deeply experienced in patent litigation.

The Verdict's Echo

While both companies declined to comment on Wednesday, the implications are clear: this latest ruling tilts the momentum in Google’s favor, but leaves many battle lines still open. With millions of dollars, brand reputations, and the future of smart audio technology hanging in the balance, the courtroom chorus between Sonos and Google is far from its final note.