The engine
The take never depends on the network.
Here’s the engine underneath.
SessionLinked streams lossless 24-bit multitrack between Logic Pro sessions on Mac (more DAWs coming). Underneath it is a transport engine built for hostile networks: forward error correction that heals losses without waiting a round trip, retransmission for whatever’s left, FLAC compression on the wire, and a clock that never guesses. We measure it the way we expect you to doubt it.
Torture matrix
One stereo 24-bit/48kHz track of musical material, streamed at the real packet rate through simulated network profiles. “Retransmit only” is a conventional recovery design; “Full engine” is what two SessionLinked Macs negotiate automatically.
| Network | Engine | Delivered | Permanent gaps | Wire data |
|---|---|---|---|---|
| Studio LAN1ms, lossless | Retransmit only | 100% | 0 | 100% of raw |
| Studio LAN1ms, lossless | Full engine | 100% | 0 | 39% of raw |
| Transatlantic75ms, 0.5% loss | Retransmit only | 100% | 0 | 100% of raw |
| Transatlantic75ms, 0.5% loss | Full engine | 100% | 0 | 40% of raw |
| Bad Wi-Fi3% loss + fades | Retransmit only | 99.5% | 1 | 156% of raw |
| Bad Wi-Fi3% loss + fades | Full engine | 100% | 0 | 54% of raw |
| Choked uplinknarrower than one raw track | Retransmit only | 65.5% | 51 | 208% of raw |
| Choked uplinknarrower than one raw track | Full engine | 100% | 0 | 39% of raw |
Measured 2026-06-11, engine 1.7.54, 200-packet runs at the real packet cadence, on simulated network profiles — not a live session. In real sessions today the live monitor can still drop out for up to about a second on a rough connection; we’re still finishing it. Your takes are recorded locally and byte-verified, so they don’t depend on it.
And then we left it running for two hours
Sessions are hours, not seconds. The full engine streamed the transatlantic profile continuously for 120 minutes — 337,500 packets, 100.000% delivered, zero gaps, 16,511 losses healed in-flight, and flat memory across every checkpoint.
Compression is resilience, not just savings
The choked-uplink row is the whole story. When the pipe is too narrow for a raw track, retransmitting harder just fills the queue faster — a third of the audio never arrives. FLAC shrinks the stream to ~39% of raw, the queue never fills, and the problem ceases to exist: 100% delivered on a link that drops 34% of a raw stream.
Losses heal without waiting a round trip
Parity packets travel with the audio, so a lost packet is rebuilt from its neighbours the moment they arrive — no “please resend” across the Atlantic. Retransmission still backstops anything parity can’t reach. On a clean link, neither costs you a byte: parity stops flowing entirely.
Lossless means lossless
Every delivered packet is byte-exact — FLAC is lossless and every packet is checksummed end-to-end. And the recording never depends on the network at all: your collaborator’s DAW captures everything locally, and the cloud reconciles any take the stream couldn’t complete.
Honest methodology
Simulated profiles are seeded and deterministic, but configurations aren’t packet-for-packet A/B comparable; read the columns as representative behavior. Engine layers were forced on/off to isolate them — a real session negotiates everything automatically, including falling back to raw PCM whenever that’s the better choice.
Hear it yourself
The engine ships in every SessionLinked install — there is no “pro transport” tier. It’s in final live verification now; join the early-access list and record someone an ocean away the day it clears.
Get early access