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What is NOT Cable?
NOT Cable makes the computers and small boards on one local network behave as a single sound system. A source turns music into timestamped network packets, and every receiver plays those packets against a shared clock. The result is one broadcast heard at the same instant at every point.
No construction work, no speaker cabling, no separate player at each point. The network is already in place.
The problem it solves#
There are two known ways to get sound from several points in one space. The first is running speaker cabling through the building. The second is putting a separate player at every point.
With the second, even a tenth of a second is audible. Walking down a corridor the song seems to start again, and between two rooms you get an echo. Separate players cannot hold the same instant even when they play the same list.
NOT Cable closes the gap between the two. No new cable is needed, and sync comes from the shared timeline written onto the packets.
How it works#
The short answer: it sends time, not just audio.
Every audio packet carries the moment it is to be played. Receivers do not play a packet when it arrives, they play it at the moment written on it. Small network delays therefore do not break sync, because the packet arrives early and the receiver waits its turn.
| Step | What happens |
|---|---|
| Source | Encodes the music and stamps the playback time on it |
| Network | The packet is sent once and the network delivers it to all |
| Buffer | The receiver queues packets and absorbs network jitter |
| Playback | Sound comes out at the stamped moment, the same moment everywhere |
The clock channel flows independently of audio. It keeps running even when the music stops, so a track that starts hours later still starts in sync.
What belongs to NOT Cable#
The whole chain was developed by notFM. No off-the-shelf codec was taken and a network built around it.
- NMC, the notFM Media Codec. A music codec designed not merely to compress audio but to play it timed across a network.
- NAP, the network protocol that carries audio packets and the shared timeline.
- .nfa, the broadcast-ready stream file format.
All three specifications are public. See NMC, NAP and .nfa for detail.
Next#
The system has two pieces, and they are two separate programs. Studio and Receiver explains what each one does and which machine it belongs on.