# Why the start of sounds gets cut off on AirPlay

> Short alerts and the first moment of audio can arrive late or clipped over AirPlay from a Mac. It's the stream going to sleep during silence. Here's how to keep it awake.

Updated 2026-10-06. Canonical page: https://lagless.app/guides/airplay-sound-cut-off-at-start/

> The start of a sound gets lost or delayed because AirPlay suspends the stream when your Mac goes quiet, then negotiates a new stream when sound resumes, which takes about 370 ms. Playing inaudible noise keeps the stream open. Digital silence doesn't work, because the driver detects it.

## What's happening

macOS's AirPlay driver watches for silence. When there's none to play, it suspends the stream; when sound starts again, it negotiates a brand-new remote stream. The [Preroll README](https://github.com/ksha23/preroll) describes this as the bottleneck that appears once the 2000 ms buffer is lowered, and puts the renegotiation at about 370 ms.

That's why a notification chime or the first click after a pause feels later than the rest, and why very short sounds can seem clipped.

## Keeping the stream awake

Pure digital silence doesn't help: the driver has `enableSilenceDetection` and `enableNonZeroPCMSampleDetection`, so it can tell. Preroll's approach, which Lagless uses, is to play never-zero random noise at −78 dBFS, far below what you can hear, so the stream never looks idle.

In [Lagless](/), this is **Keep Speaker Awake**. It only plays while your output is an AirPlay device, and stops when you switch to anything else.

## Questions

### Will I hear the noise?

At −78 dBFS it's far below normal listening levels. If you turn a speaker right up in a silent room you might, so you can switch it off.

### Does it use battery?

A little, like any audio playing. It stops when you're not on AirPlay.

## Sources

- [Preroll README](https://github.com/ksha23/preroll)