A real heartbeat, synthesized live
Every beat you hear is built in the moment with the Web Audio API - no recordings, no loops that repeat in an obvious way. Each beat is the familiar two-part "lub-dub": a slightly louder first thump (the "lub", around 55 Hz) followed quickly by a softer second thump (the "dub", around 50 Hz), shaped through a gentle lowpass so it stays soft and round with no clicks or pops.
Getting a sound you like
- Start with a preset. Resting (60) is a calm adult pulse, Sleeping (50) is slower and deeper for winding down, and Calm (70) sits in the relaxed-but-awake range.
- Set the speed. Drag the BPM slider anywhere from 40 to 100, or use tap tempo to match a pace you have in mind.
- Shape the warmth. The depth and warmth control opens or closes a lowpass filter. Lower is warmer and more muffled, like a heartbeat heard from inside; higher lets a little more of the thump through.
- Add the background bed. Turn on the womb bed for a soft, filtered whoosh that swells underneath the beat, close to the muffled blood-flow sound a baby hears in the womb.
- Set a sleep timer. Choose 15, 30, or 60 minutes and the sound fades out slowly at the end so it never stops with a jolt.
Who it is for
People reach for a steady heartbeat for all kinds of reasons. We put together focused guides for the most common ones: soothing a newborn with a heartbeat for babies, winding down at night with a heartbeat for sleep, grounding yourself during a tense moment with a heartbeat for anxiety, and settling a nervous puppy or dog with a heartbeat for pets.
A note on safe, sensible use
This is a comfort and relaxation tool, not a medical device or a substitute for care or advice from a professional. If you are using it around a baby, keep the volume low and the speaker across the room rather than next to their head - the American Academy of Pediatrics suggests keeping sound machines below about 50 decibels and at least 7 feet from the crib. For everyone, start quiet and use the lowest volume that feels soothing.
More from the Audio Tools Network
If you like steady, calming sound, you might also enjoy soft white, pink, and brown noise from Focus Hum, slow ocean waves, or ambient meditation drones from OmTones.