US 6,631,410 · Granted 2003-10-07

The Patent That Keeps Your Music in Sync Across Every Room

Imagine streaming a song to speakers in your bedroom, living room, and kitchen at the exact same time — but they're connected by different methods (some wired, some wireless). This patent solves the tricky problem of keeping all those speakers perfectly in sync so you don't hear an echo or lag. It's the invisible choreographer behind whole-home audio.

Curated and verified by the IsItPatented Editorial team

The plain-English version

What it protects

The claims cover a system and method for synchronizing multimedia streams to multiple output devices connected through a mix of wired and wireless connections. Specifically, what's protected is the process of buffering content, calculating the delay needed for different connection types, and then broadcasting that delay information to all devices so they play at the exact same moment. The patent also protects the architecture of organizing devices into separate 'realms' (wired and wireless groups) that are managed by control units.

Why it matters

Sharp filed this in 2000, right when home networking was emerging and wireless audio was still experimental. The patent addresses a real engineering challenge: wireless devices are inherently slower and less predictable than wired ones, so without active synchronization, multi-room audio systems would sound broken. This kind of patent became foundational for companies building whole-home entertainment systems — the kind you see in high-end home automation today.

Real-world use

When you use a modern multi-room audio system like Sonos or Apple AirPlay to play music simultaneously in your kitchen and living room, synchronization logic based on concepts from patents like this one keeps the sound from arriving at different times.

Original USPTO abstract

A system for synchronizing a multimedia content stream signal, emanating from at least one multimedia source, for play through a plurality of output devices, wherein the output devices are connected to the multimedia source by wired connections and wireless connections; the system including plural output realms, including wired realms and wireless realms; and which includes delay synchronizers and for determining a buffer delay for streaming the multimedia content stream signal from a buffer to an output device. A method of synchronizing a multimedia content stream for output to a plurality of wired and wireless output device in a network having plural realms, wherein each realm includes a CTL, includes buffering the multimedia content stream in a first realm; determining a buffer delay; transmitting the buffer delay to all CTLs in all realms of the network; and transmitting the multimedia content stream to all realms in the network.

Patent details

Publication number: US 6,631,410
Filing date: 2000-03-16
Grant date: 2003-10-07
Assignee: Sharp Laboratories Of America, Inc.
Inventor(s): KOWALSKI JOHN MICHAEL, ISHII ATSUSHI
CPC class: H04N5/0736

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