How to fix crackling or popping sound on a Mac's speakers

Crackling or popping sound on a Mac is usually one of five things: a sample rate mismatch between an app and the output device, a Bluetooth codec or interference problem, an overloaded Core Audio process, USB power management suspending an audio interface, or a genuinely faulty cable. Each has its own fix, and none of them needs a reboot.

These causes have a rough order of likelihood, and it pays to check them in that order rather than jumping straight to the most drastic fix. A sample rate mismatch explains most crackle on USB DACs and audio interfaces. Bluetooth crackle has its own separate causes. A stuck Core Audio process explains crackle that appears suddenly, on any output, for no obvious reason. USB power management explains crackle that comes and goes on a schedule. A faulty cable explains crackle that survives every software fix.

Why does my Mac's audio crackle or pop?

Underneath every output device, macOS runs an audio pipeline that has to agree on a sample rate, the number of times per second the audio signal is measured, between the app sending sound and the device receiving it. When the two disagree, macOS has to resample on the fly, and a resample that is not clean produces exactly the short, sharp clicks and pops people describe as crackling. This is the single most common cause with USB DACs and audio interfaces, because those devices let you set a fixed sample rate by hand in a way that a Mac's built-in speakers do not.

How do I check for a sample rate mismatch in Audio MIDI Setup?

Open Audio MIDI Setup, in Applications > Utilities. Select the device that is crackling in the list on the left, and look at the Format dropdown along the bottom of the window. It will show a number like 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz. Compare that to the rate the app playing audio expects, which is 44.1kHz for most music files and 48kHz for most video and conferencing apps. If the two do not match, set the device's Format to 48kHz, since that rate is supported natively by almost every app and interface and gives macOS the least resampling to do.

A mismatch often appears after another app quietly changes the device's rate behind your back, which some music production and video software does on launch. Quitting and reopening the app that is currently playing, after fixing the Format in Audio MIDI Setup, clears the crackle in most cases without touching anything else.

Bluetooth crackle: codecs, interference, and low-power mode

Bluetooth audio has its own reasons to crackle that have nothing to do with sample rates. macOS sends audio to Bluetooth headphones and speakers using AAC by default, falling back to the lower-quality SBC codec when a device does not support AAC, and either codec depends on a steady stream of small packets arriving on time. Anything that interrupts that stream produces crackle or brief dropouts rather than silence.

Two things interrupt it most often. Wi-Fi at 2.4GHz shares the same radio band as Bluetooth, so heavy network traffic, like a large download or a video call running alongside Bluetooth audio, can crowd out the audio packets. And many true wireless earbuds switch into a low-power mode to save battery, which shrinks their audio buffer and makes them more sensitive to any interruption. Moving the Mac and the router further apart, switching Wi-Fi to the 5GHz band where the router supports it, and keeping Bluetooth devices charged above roughly 20% all reduce how often this happens.

Restart Core Audio with one Terminal command

When crackle appears suddenly, on every output, for no obvious reason, the cause is often coreaudiod, the background process that manages every audio device on the Mac. Like any long-running process it can get into a bad state, particularly after a Mac wakes from sleep with several audio devices connected. Open Terminal and run:

sudo killall coreaudiod

This restarts the audio daemon from scratch without rebooting the Mac. Whatever is playing cuts out for a second or two while it restarts, and every connected device briefly disappears and reappears in the menu bar, but that is the entire effect. It does not touch any files, does not need to reconnect Bluetooth devices manually, and causes no data loss. It is one of the few times a sudo command is genuinely low-risk, because macOS restarts coreaudiod automatically the moment it is killed.

USB power management can put an audio interface to sleep

Apple Silicon Macs manage USB power aggressively to save battery, and a USB audio interface that sits idle between playback can have its port suspended and then briefly reconnected the moment audio starts again, which produces a short pop or click right at the start of playback rather than throughout it. This is more common on battery than when a Mac is plugged into power, and more common with bus-powered interfaces that draw all their power from the USB port itself.

Keeping the Mac plugged into power while an interface is in regular use, or connecting the interface through a powered USB hub rather than directly to a battery-conscious port, both reduce how often the port gets suspended in the first place.

When it's actually the cable or port

Once a sample rate mismatch, Bluetooth interference, a stuck Core Audio process and USB power management have all been ruled out, what is left is the least interesting explanation and, for a wired connection, often the correct one: a worn cable, a loose connector, or a port with a bent pin or corrosion from moisture. Swap the cable for a known-good one, try the same connection in a different USB or headphone port, and if possible test the speaker or interface on another Mac. If the crackle follows the cable or the port rather than the Mac, that confirms it and rules out everything above.

For the step-by-step on building a Multi-Output Device, see Apple's own guide to Audio MIDI Setup.

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