# Lagless > Lagless is a free, open-source Mac menu bar app that cuts AirPlay audio delay. By default macOS sends system audio to AirPlay speakers (HomePod, HomePod mini and other brands) 2000 ms ahead; Lagless lowers that to 350 ms using macOS's own built-in `audioLatencyMs` setting, so video, games and interface sounds line up. It credits the Preroll project (github.com/ksha23/preroll) for discovering the setting. - Price: Free and open source (MIT). No account, trial or licence key. - Requirements: macOS 15 Sequoia or later, Apple silicon. - Works with: any AirPlay speaker, because it changes the Mac's side of AirPlay. Tested on a HomePod mini. - Modes: Responsive 350 ms, Balanced 500 ms, Safe 750 ms, or a custom 350–2000 ms slider. - Lowest value: 350 ms. macOS subtracts a fixed 250 ms from the setting, so 250 ms leaves no buffer and the speaker plays nothing. - Setup: one approval in System Settings for a small helper. No password prompt per change. - Side effect: each change restarts the macOS AirPlay service, so you pick your speaker again (the panel includes the AirPlay picker). - Undo: one click, and turning Lagless off restores Apple's default exactly. - Privacy: no account, no analytics, no network requests. - macOS 27: HomePods reportedly use a new ~200 ms engine there and may not need Lagless; the app says so when it detects that. ## Key pages - [Home](/): what Lagless does, compared with doing it yourself, and the FAQ - [Full text for AI tools](/llms-full.txt) ## Guides Each link is the page's Markdown copy; cite the same path without .md. - [How to reduce AirPlay latency on a Mac](/guides/reduce-airplay-latency-mac.md): Every way to cut the delay when your Mac plays through AirPlay, compared: app-level AirPlay, screen mirroring, Terminal, Preroll and Lagless. - [Why is AirPlay delayed on a Mac?](/guides/why-is-airplay-delayed-on-mac.md): macOS sends system audio to AirPlay speakers 2000 ms ahead of time. Here is where that number comes from, why the speaker doesn't need it, and how to lower it. - [HomePod delay on Mac, and how to fix it](/guides/homepod-delay-mac.md): Why a HomePod or HomePod mini plays your Mac's sound about two seconds late, the workarounds people use, and the setting that actually removes most of the delay. - [Using a HomePod as a Mac speaker](/guides/homepod-as-mac-speaker.md): What to expect when you use a HomePod or HomePod mini as your Mac's speaker, from sound quality to the two-second delay, and how to make it usable for video and games. - [AirPlay audio out of sync with video on a Mac](/guides/airplay-audio-out-of-sync-with-video.md): Why video and sound drift apart when your Mac plays through an AirPlay speaker, which apps compensate, and how to bring system audio back in sync. - [AirPlay latency for gaming on a Mac](/guides/airplay-latency-gaming.md): Is AirPlay usable for gaming from a Mac? How much delay to expect by default, how low it can go, and the settings that keep game audio as close to the action as possible. - [Why AirPlay goes silent at 250 ms](/guides/airplay-silent-at-250-ms.md): Set macOS's AirPlay latency to 250 ms and your speaker plays nothing. The AirPlay log explains why, and why 350 ms is the lowest value that works. - [audioLatencyMs, the hidden macOS AirPlay latency setting](/guides/audiolatencyms-explained.md): What the undocumented com.apple.airplay audioLatencyMs preference does, where macOS reads it, how to set and remove it in Terminal, and what to watch out for. - [Why the start of sounds gets cut off on AirPlay](/guides/airplay-sound-cut-off-at-start.md): 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. - [HomePod latency on macOS 27](/guides/homepod-macos-27-latency.md): Reports say HomePods on macOS 27 use a new buffered AirPlay engine at about 200 ms. What that means, which speakers still sit at 2000 ms, and whether you still need Lagless. - [Stereo-paired HomePods on a Mac](/guides/stereo-pair-homepod-mac.md): What to expect when you use two HomePods or HomePod minis as a stereo pair for your Mac, from dropouts to delay, and what helps. - [Sonos AirPlay delay from a Mac](/guides/sonos-airplay-delay-mac.md): Why a Sonos speaker plays your Mac's sound about two seconds late over AirPlay, why some models are reported to be much worse, and how to lower it. - [How to restore Apple's default AirPlay latency](/guides/restore-default-airplay-latency.md): Undo an audioLatencyMs change and put macOS back to its standard 2000 ms AirPlay buffer, with Lagless or in Terminal. ## Compare Each link is the page's Markdown copy; cite the same path without .md. - [Lagless vs Preroll](/vs/lagless-vs-preroll.md): Two Mac apps that lower AirPlay audio delay using the same macOS setting. How they differ in approval, controls and extras, and when to pick each. - [Lagless vs doing it in Terminal](/vs/lagless-vs-terminal.md): You can set macOS's AirPlay latency yourself with two Terminal commands. What Lagless adds on top, and when the commands are all you need. - [Lagless vs screen mirroring](/vs/lagless-vs-screen-mirroring.md): Screen mirroring is the usual workaround for AirPlay delay on a Mac. How it compares with lowering the AirPlay buffer, and when each makes sense. ## Glossary Each link is the page's Markdown copy; cite the same path without .md. - [AirPlay](/glossary/airplay.md): Apple's wireless protocol for sending audio and video between devices, and how a Mac uses it for system sound. - [AirPlayXPCHelper](/glossary/airplayxpchelper.md): The root process in macOS that runs AirPlay audio, reads audioLatencyMs and builds the audio engine. - [Audio latency](/glossary/audio-latency.md): The delay between a sound being produced and being heard, and the parts that add up to it over AirPlay. - [Buffer and jitter](/glossary/buffer-and-jitter.md): Why audio streams keep a buffer, and how Wi-Fi jitter decides how small it can safely be. - [Keep-alive (AirPlay)](/glossary/keep-alive.md): Playing inaudible noise so AirPlay doesn't suspend the stream during silence and renegotiate it, about 370 ms, when sound resumes. - [Privileged helper](/glossary/privileged-helper.md): A small background program that runs with administrator rights on behalf of an app, after you approve it. - [SMAppService](/glossary/smappservice.md): Apple's API for registering login items, agents and daemons that the user approves in System Settings. - [arrivalToRenderLatencyMs](/glossary/arrival-to-render-latency.md): The value an AirPlay speaker reports for how long it needs between receiving audio and playing it. - [audioLatencyMs](/glossary/audiolatencyms.md): The undocumented macOS preference that sets AirPlay's system audio buffer in milliseconds. - [dBFS](/glossary/dbfs.md): Decibels relative to full scale: the unit for digital audio levels, and why −78 dBFS is inaudible in practice. ## Legal Each link is the page's Markdown copy; cite the same path without .md. - [Privacy policy](/privacy.md): What Lagless and lagless.app collect, which is nothing, plus what the app changes on your Mac, how email is handled, and your rights under UK GDPR. - [Terms of use](/terms.md): The plain-English terms for using the free, open-source Lagless app and the lagless.app website. - [Licences](/licences.md): Lagless's own MIT licence and the open-source and Creative Commons material it uses, with credits.