Background: Sound Around the House

EdS did not bring music to the rooms of the house. A whole-house digital audio system was already doing that, was built years before EdS, and carries on exactly as it did. EdS listens in on it. This page is the short version; the project’s own page has the whole of it: S/PDIF Audio Distribution.

Whole-house digital sound distribution

One digital feed (S/PDIF) is sent from the basement to every room, and each room’s own stereo plays it.

Listening areas

• Home office and vinyl listening room: the primary listening room, and home of the record collection.
• Family room home theater, which covers the family room and the kitchen.
• Master bedroom, on a vintage Marantz.
• Retro gaming room, on a vintage Carver system like the one in Ferris Bueller’s Day Off.
• Outside: speakers fed from the basement, and an FM transmitter that carries the feed to a vintage boom box.

The media server and its sources

A media server in the basement plays the house’s music, from more than one source:

• Local collections, in iTunes and MusicBee.
• Streaming services, Spotify and Tidal among them.

It is the house’s central digital library and its gateway to streaming, and its digital output is the primary source for every room.

The digital S/PDIF switch

Before the music is sent through the house, the media server’s sound card digital output passes through an automatic digital switch. The media server is on the switch’s primary input, and its other inputs are overrides: when a signal appears on one, the switch passes that source to the house instead, and when the signal goes away, the media server has the house back. Nobody presses a button.

Switching between the turntable and the house music

The turntable is one of those overrides. The home office stereo’s analog output, with the turntable playing through it, is converted to digital and sent to the switch as its second input.

Wiring it in directly is not enough for the switch to change over by itself. The converter (an ADC) sends a signal whenever it has power, even with nothing playing, so the switch would never hand the house back. A smart power strip was added so that the ADC has power only while the turntable does.

The result: turn on the turntable, and the house’s music is the spinning record. Turn it off, and the media server has the house back.

Why this matters to EdS

• EdS can fail without the music noticing. Every part of EdS can be off and a record still plays in every room.
• The house already knows some things. The power strip answered “is the turntable on?” long before EdS asked; EdS reads the same strip (ADR-0023).

How EdS hears the feed and the strip is in Now Playing.