Once a home theater is finished, acceptance is not over when it "sounds fine". Even cutouts or not, every channel playing or not, boomy bass or not, audio and picture in sync or not - these four kinds of problems can be found on the day of installation. Leave them until after move-in and the cost of a rework is taking the ceiling apart.
This article gives you a checklist you can tick off on site, item by item: 8 items, half an hour to walk through.
1. Cutouts and workmanship: start with "even or not"
- Panel flush with the ceiling surface: run a hand across it, no step, an even gap; a lifted panel edge means the cutout is off center or a joist is in the way.
- Grille grip: all four corners should hold, and a light push with a finger should not move it.
- Filler and paint: no cracks at the cutout edge, especially where gypsum boards are joined.
- Cutout size: measure it with a tape, it should match the model specifications (CW90 Ø90mm, IW3max Ø85mm).
2. Channels and levels: each one must play on its own
| Check | Method | What a failure looks like |
|---|---|---|
| Channel-by-channel playback | Test tone from the amplifier, walk left, center, right and surround one at a time | One unit silent, or two units bleeding into each other |
| Left and right balance | Pink noise, listen from the main seat | One side clearly louder |
| Phase | Switch 0°/180° and listen to the bass | Bass sounds hollow and cancels out |
| Level match | SPL meter or a phone app | Channels differ by more than 3dB |
3. Low frequency: listen from three seats in the room
Bass is not about "loud enough", it is about "even enough". Ask the owner to sit in the left, middle and right seat of the sofa for 30 seconds each:
- A big difference between the three seats ⇒ standing waves are obvious, adjust the subwoofer position or phase before anything else.
- One seat booms badly ⇒ that spot sits on a standing-wave peak, move the subwoofer or add a bass trap.
- No weight overall ⇒ check the crossover point and the subwoofer level before considering a different subwoofer.
4. Sync and latency: where movie playback shows problems
- Audio and picture sync: play a dialogue-heavy clip and watch lip movement; a gap over 40ms is noticeable.
- Wireless latency: 5.8GHz systems such as the CW90 usually run 10–20ms; fine-tune once more in the player.
- Source switching: from TV to player, from 4K to 1080p, the sound must follow and must not drop.
5. Control and network: the last step before handover
- The remote or app can power on and off, switch sources and adjust volume; for a Bluetooth remote, confirm it is paired.
- Join the home Wi-Fi once and confirm the app connects; Mijia version devices should be found in the Mijia app.
- Walk through the usual scenes (movie, music, karaoke) one at a time and confirm switching does not black out the screen and does not mute the sound.
6. The 8-item acceptance checklist (tick each one)
| # | Item | Pass criteria |
|---|---|---|
| 1 | Panel flush | No step, even gap |
| 2 | Cutout size | Matches the model specifications |
| 3 | Channel playback | All 5 (or 7) play on their own |
| 4 | Level and phase | Channels within ≤3dB, bass does not cancel |
| 5 | Bass evenness | Difference across the three seats is acceptable |
| 6 | Audio and picture sync | Lip movement matches |
| 7 | Control and network | Remote, app and control system all work |
| 8 | Cable termination | No exposed cable, no temporary wiring |
7. When you should not sign
- One speaker does not play and the installer says "it will settle after a break-in period" - it will not; it is a wiring or an amplifier channel problem.
- The panel is clearly lifted and they say "a bit of paint will hide it" - paint does not hide a step.
- The bass sounds good in just one seat on the sofa - that is a tuning problem, not the room.
- The remote works intermittently - change the batteries, then check pairing, do not rush to swap the device.
8. Common questions
Q: Should I bring in a third party for acceptance?
For a system costing tens of thousands, yes; for a kit in the ten-to-twenty-thousand range, walking through these 8 items yourself is basically enough.
Q: The crew says "we will tune it after installation" - is that fine?
Levels and phase must be set on the spot once installation is done; after the ceiling is patched and painted, neither tools nor people can get up there.
Q: How do I set levels without an SPL meter?
A phone app is enough; an error of 1–2dB is acceptable in a home environment.
Q: Once acceptance finds a problem, how soon must it be fixed?
Cutout and panel issues should be raised the same day; acoustic issues can be booked for a follow-up tuning within a week.
9. Matching configurations
Common combinations accepted with this checklist: CW90-W10 5.1 wireless set (from ¥17,200), IW3max-C110 5.1 in-ceiling set (from ¥23,600); for larger rooms, see X-Series-714B 7.1.4.
One-line verdict
The order of acceptance is: workmanship → channels → bass → sync → control. The opening two can be judged on the spot, the last three need sitting down to listen; sign after all five pass, which is far cheaper than rework later.
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Written by Digital Xiaoniu, first published on the SNAIL POWER official site, Other.