FCME · Front-row Center MultiMedia Experiences

Sync Lab — Guide

How to read and drive the Sync Lab: what each control does, how it changes what you see and hear, the trade-offs of screen delay in live vs. remote venues, and the takeaways that matter.

What the Sync Lab shows

Public venues are full of big screens, but the sound is the missing half of the experience — a dozen TVs and one muddy feed, or a stadium screen no one can really hear. FCME delivers high-fidelity audio, perfectly lip-synced to any screen, to every guest's own phone and earbuds.

The Sync Lab makes the underlying timing tangible. It has one shared set of controls and three lenses on the same scenario:

Tab	What it shows
Timeline	The abstract latency stack for a listener — where the delay comes from, and when picture vs. sound arrive.
Concert Hall	A stage-at-one-end venue: left/right sound-reinforcement arrays firing forward, sound propagating out to the seats.
Arena (MSG)	A center-hung display with sound propagating 360° into the stands.

Set a scenario once, then flip tabs to see it three ways. The single most important control is Auto-Sync — off shows the problem, on shows FCME solving it.

Controls reference

Grouped as they appear in the panel. "What changes" describes the visible/audible effect.

Control	What it does	What changes
Auto-Sync core	The FCME action itself: holds the in-line display back to meet the audio, and compensates each listener's device individually.	Off → picture and sound are apart (out of sync). On → they converge; seats flash with the screen; verdict reads IN SYNC.
Earbud technology Standard earbuds (real mix) / Auracast	Standard earbuds — real mix (the default) seats the room with the realistic spread of earbuds guests actually carry — AirPods ≈120 ms, SBC ≈160, LDAC ≈240, gaming ≈55 — so no single offset can sync them all. Auracast is the low-latency (~40 ms) broadcast alternative, but only ~25–35% of earbuds support it (AirPods excluded).	Sets the SOUND-path length and the earbud floor. In the mix, seats flash at different times with Auto-Sync off and converge when on; the timeline shows one bar per device topped by an orange compensation segment. In Live mode, shifts the display delay D and the binding constraint.
FCME Secure Wi-Fi Multicast	FCME's own transport latency — part of every listener's audio path. This is FCME's real lever on the floor (you can't choose guests' earbuds).	Lowering it shortens every SOUND path and lowers the earbud floor for the whole room.
Display processing / panel	The display's own intrinsic latency, before any FCME buffering.	Sets the base of the PICTURE bar and how much buffer FCME must add to reach the sync point.
Venue size venue	Venue scale in metres.	Changes seat distances → the acoustic arrival spread (nearest/farthest/spread) and, in Live mode, the room centroid.
Event: Remote / Live venue	Remote = content from elsewhere (a sports bar) → no live reference. Live = a co-located event the crowd also sees/hears directly.	Live reveals the Acceptable screen-lag slider, relabels the metric tiles (floor / centroid / D / worst mismatch), and rings each seat green→red by its mismatch to the live room.
Acceptable screen-lag (live) live	The soft tolerance ceiling — how much the screen may lag the real action before it distracts. Content-dependent.	Caps the display delay D; can flip the binding constraint. Raising it can be a legitimate design choice (see below).
Show PA waves venue	Show/hide the acoustic wavefronts and per-seat room-sound pulses.	Red expanding wavefronts + red seat pulses (the raw room sound).
Delay towers concert	Show the delay-tower reinforcement far venues use today. A level/coherence aid — it does not change timing.	Orange arcs that fire as the main front passes each tower. Does not change any mismatch number.
Sound Off / Speakers / Earbuds	Tap to cycle Off → 🔊 Speakers → 🎧 Earbuds. Speakers plays with no timing correction; Earbuds compensates for Bluetooth's delay (the browser can't auto-detect it — why below). Sits beside Auto-Sync, above the display.	A high click at the picture and a beep at the earbud audio — a distinct per-device pitch in the real-mix. Under Auto-Sync they lock together.
Pause / Play	Freeze the animation where it is, and resume.	Everything holds in place, then continues.

Reading the picture

Timeline tab

Latency bars — the PICTURE path (display + FCME buffer) and the SOUND path (Wi-Fi + Bluetooth). In device-mix mode there's one SOUND bar per device, each topped with an FCME compensation segment to a common line.
Sound Arrival Time — a PICTURE marker and SOUND marker(s) with a sweeping playhead. In device-mix mode the per-device dots spread apart with Auto-Sync off and converge under the picture when on.
Verdict — IN / OUT of sync (±45 ms counts as imperceptible), the offset, and the display buffer FCME added.

Venue tabs

The screen flashes on each picture frame; seats flash gold when their earbud audio arrives — together when synced.
Red wavefronts and red seat pulses are the raw room sound (the PA through the air, 343 m/s).
Gold dashed sweet-spot = where room sound naturally matches the synced experience.
Seats are cyan (or device-tinted in mix mode); in Live mode each also gets a green→red ring showing its mismatch to the live room.
Metric tiles show acoustic nearest/farthest/spread/earbud (Remote) or earbud-floor / room-centroid / D / worst-mismatch (Live). Click any seat to inspect its exact numbers.

Why it asks: Speakers or Earbuds?

Turn Sound on and the lab asks how you're listening. That prompt isn't a quirk — it's the whole problem in miniature, and it's one of the clearest arguments for why FCME has to exist.

The delay between "a device plays a sound" and "your ear hears it" varies enormously — phone, OS, codec, and above all the earbuds — from near-zero on a built-in speaker to 100–250 ms+ on Bluetooth. And a web browser has no reliable way to measure it: the one latency figure it can read is incomplete and, on phones, doesn't even update when you switch from the speaker to Bluetooth. Bluetooth is the worst offender — for most of its history it never reported its own latency at all.

Everyone hits this wall, and how they cope is telling. Video players keep lip-sync by locking the picture to the audio clock and delaying the video to match — and they only stay perfect on AirPods because Apple owns that whole stack and AirPods report their exact delay. Every rhythm game (Beat Saber, Guitar Hero) ships a "tap to the beat" calibration screen, because the platform can't hand it a trustworthy number either. So the lab does the honest thing and simply asks: 🔊 Speakers (≈ no delay to correct) or 🎧 Earbuds (compensate for Bluetooth). Pick the one that matches how you're listening and the cues line up.

This is exactly why FCME has to exist. A personal app can hide all of this by delaying its own screen for its one device. But a shared public display can't be delayed differently for every guest, and no room full of strangers' phones will report its true latency. The only thing that works is to own the endpoints and measure the real per-listener delay — precisely what FCME's app, hotspot, and in-line display controller do together, and what a browser (or a generic video app) fundamentally cannot.

The real trade-off: screen delay in live vs. remote venues

Here's the crux. FCME solves lip-sync per listener regardless of screen delay, so how the shared display is timed only matters against the real event the audience also perceives.

Remote-viewed venues (sports bars — most of the market)

The content is from elsewhere, so there's no live reference in the room. The display can be delayed freely; FCME simply syncs everyone. No constraint, no trade-off. This is the common case, and it's trivial — switch Event to Remote and there's nothing to optimize.

Co-located live events (stadiums, concerts)

Now the crowd also sees and hears the real action, so the display delay D is a negotiation between three forces:

Force	Meaning	Lever
Earbud floor (hard min)	The display must lag at least the slowest listener's audio path, or their earbuds can't sync.	FCME: faster Wi-Fi multicast; lower-latency earbuds.
Room centroid (target)	Ambient sound arrives at the average seat at this time — the best single value for the whole room.	Venue geometry (below).
Tolerance ceiling (soft max)	How much the screen may lag the real action before it distracts — content-dependent.	Content choice; sometimes a feature.

Optimal D* = clamp(centroid, floor, ceiling). The lab names which force is binding: earbud pipeline (lower the floor), tolerance (raise the ceiling or tighten the room), or optimal.

A deliberate delay can be a feature — not a distraction. For many event types, intentionally delaying the jumbotron by the optimal amount makes the whole mediated experience — the screen plus perfectly-synced hi-fi audio in every ear — internally coherent, and often more immersive than raw distant action with muddy far-field sound. So the ceiling is a design choice, not a hard wall.

What actually shrinks the room mismatch — and what doesn't. The residual comes from the spread of acoustic arrival times across seats. You shrink it with geometry: less seating depth, or a more central sound source (compare the Arena's tighter spread to the Concert's). Delay towers do not help here — they're time-aligned to the main front, so they fix level and coherence for far seats but preserve the natural distance-based timing, leaving the spread unchanged.

Because it responds to both the audio pipeline and the room, this view doubles as a stage / venue / display layout optimization aid.

Key takeaways — FCME's value

Perfect lip-sync, in-line. FCME sits in-line with the display and holds the picture to meet the sound — frame-accurate, not "close enough."
No single offset works — so FCME compensates each listener. Two guests side by side can differ by 120+ ms (AirPods ≈125 ms vs. LDAC ≈246 ms). A shared display can't be delayed per-person, so FCME adjusts the audio at each endpoint.
The whole room, not a third of it. Works with standard Bluetooth on the phone guests already own. An Auracast-only solution reaches ~25–35% of earbuds (AirPods excluded); FCME reaches ~everyone — and can still use Auracast where present.
Two-way, on proven infrastructure. FCME Secure Wi-Fi Multicast runs on standard Wi-Fi APs and is bi-directional — enabling per-guest screen selection, polls, and interaction that a one-way broadcast can't.
Built for protected content and engineered to scale from a bar to a stadium.
The experience is the metric. Not a spec sheet — one outcome: everyone hears in sync with what they see, from any seat in the house.

A 60-second demo path

Open the Concert tab. Turn Auto-Sync OFF — the screen fires, then the seats flash ~150 ms later. Turn it ON — they lock together. (That's the whole pitch.)
Turn on Sound (pick 🔊 Speakers or 🎧 Earbuds to match how you're listening). You're already in the real-earbud mix: Auto-Sync off → a staggered arpeggio of tocks (different devices, different latencies); on → a single chord. No single offset works; FCME fixes each.
Switch Earbud technology to Auracast: a lower floor, but it reaches only ~25–35% of earbuds. (The "whole room vs. a third of the room" point.)
Switch Event to Live, Auto-Sync on. Read the binding constraint; lower the Wi-Fi / raise the ceiling / shrink the venue and watch the seats go green.
Switch Event back to Remote — the constraint disappears. That's the sports-bar case: FCME just syncs everyone, free.