Why does a cheap split-screen baby monitor only play audio from one twin?

Is split-screen meant to play both babies’ sound?

No. On the kits UK parents actually buy, split-screen is two pictures, one microphone path. Babysense’s HDS2 and PRO pages say you see both babies on one screen “while the audio focus remains on one camera”. The FAQ is blunt: “Can I hear both cameras at once?” — you hear the camera being monitored; switch with a button or use SCAN.

That is why night one with twins in two rooms feels broken. The box promised “see both”. It did not promise two live speakers at once. Mixing both rooms into one speaker would also make it hard to tell which twin cried.

This is a feature limit, not a safety verdict. Official records about recalls and the Lullaby Trust’s position on monitors are separate questions from how SCAN is wired.

What do split-screen, SCAN and VOX each do to the sound?

How do I stop missing the quiet twin?

1. 1
   Confirm both cameras are paired Split-screen only appears once two or more cameras are on the same parent unit. A one-camera box will not split until you add a matching extra.
2. 2
   Tap the other pane On split-screen, one side is “live” for sound. A single press usually moves the audio focus. Watch which border or speaker icon highlights.
3. 3
   Switch on SCAN / loop Babysense’s UK Q&A: SCAN cycles paired baby units about every 10 seconds (some pages say 10–15). You will hear a slice of each room, not both at once.
4. 4
   If you use VOX at night The same Q&A says VOX typically works on the last camera selected, and across cameras only when SCAN is also on. VOX alone on split-screen is how people miss the other twin.
5. 5
   If you need two continuous audio streams Add a cheap DECT audio set in the second room, or run two full audio kits. That is a different product from one split-screen video.

Does it matter if the twins share a room?

If both babies are in one room, one camera’s microphone hears the room. Split-screen is then for a toddler next door, not for two cots a metre apart. Two cameras in one small room also risk feedback if a parent unit is nearby.

If the twins are in two rooms, the one-audio-at-a-time limit is the whole problem. SCAN is a compromise: you hear each room in turn. You will not get a continuous mix. Parents who want both cries at full volume usually keep a second audio parent unit.

In shortThe monitor is doing what the FAQ describes. Split-screen is the picture; SCAN or a tap is the sound. Two live audio streams means two baby units feeding two parent speakers, not a cheaper dual-camera video kit.

Does hearing one twin change safer-sleep rules?

No. The Lullaby Trust says monitors do not replace supervision. NHS safer-sleep advice still applies to each baby: back, clear cot, same room as you for the first six months. Two cameras mean two mains leads to keep out of reach.