LullbeeThe first sound every person ever hears is a heartbeat. It plays without pause for nine months, from the inside, louder than anything else in that small world. It should be no surprise that a slow, steady pulse remains one of the most reliable calming sounds through the whole first year.
Tempo is the whole trick
A resting adult heart sits around 60 beats per minute, and that is the pulse a baby heard most, the sound of a calm parent at rest. A heartbeat track meant for sleep should sit at that slow resting pace. Faster pulses read as activity, not rest.
Muffled beats real
In the womb, the heartbeat arrives through layers of body, so it lands as a deep, round lub-dub with no sharp edge. A good heartbeat track keeps that softness. If a heartbeat sound has a crisp, clinical thump, it tends to work less well than a low and slightly blurred one.
Layering it
A heartbeat on its own can feel sparse in a silent nursery. The classic move is layering it under something continuous, rain, a low hum, or a womb wash, so the pulse becomes a texture inside a larger blanket of sound. That combination is the closest an open room gets to the real thing.
Lullbee's heartbeat is built on an exact 60 bpm grid so the loop never drifts or stumbles, and the whole womb shelf carries the same pulse underneath its melodies.