Latency and dropouts

A dropout is a crackle, a click or a short gap in the sound: the computer didn’t finish a block of audio in time. Latency is a delay: between pressing a key and hearing it, or between what you play and where a take lands. This page helps with both.

Latency and dropouts

Available on every platform.

See what the audio is doing

The Resources gauge appears in the toolbarin the title bar when the audio or memory runs high; the same details are always in Window › ResourcesView › Resources. While a song plays, its headline reads “Audio” and the load, such as “Audio 45 %”; it turns orange past 60 % and red past 85 %, and says “Audio dropouts” when blocks come late even at a lower load. Click it for the details under Audio:

DSP load: how much of each block’s time the song’s sound takes to make, on average. At 100 % there’s no time left.
Peak: the heaviest block lately.
Blocks late (dropouts): each block that took longer than it lasts, which you hear as a dropout; “just now” counts the latest ones.
Sample rate: the output’s.

The gauge shows the song in front; starting a song stops any other that was playing. See The Resources gauge.

Lighten a heavy song

What takes the most work, roughly in order:

Amps, cabinets and impulse responses. Each amp is a full model of the circuit. Double-Tracked plays the part twice, through two lanes of the amp, so it costs about twice as much.
Sampled instruments and kits, especially many of them at once.
Recordings at a practice speed or in another key, which are stretched as they play.
Many tracks and effects in the Sound pane: reverbs, delays, the Hall with shimmer.

To find what’s heavy, play the song and watch the load while you bypass devices one at a time with their power button in the Sound pane: a bypassed device does no work.

Then, on the device itself:

Close other apps, especially other music apps, browsers with many tabs and video calls.
On a laptop, plug in the power: on battery, the system may slow down to save energy. Low Power Mode does the same.
Separating into stems and other long analyses run beside the playback and share the processor; let them finish first. In a browser, keep Stab’s tab in front: a tab in the background gets less time.

Audio Buffer, in Settings (see Settings), sets how much sound the output takes at a time. Auto, the default, keeps it short while you play live (an Instrument pane open, a MIDI device connected, an audio track armed or monitored) and longer otherwise. When Auto’s short buffer makes blocks late on a heavy song, it doubles by itself. If dropouts go on, choose a larger size, such as 512; for the quickest response while playing, a smaller one. In a browser, the browser sets the audio buffer: Stab asks for its shortest.

When what you hear is late

Stab knows how late the output is and draws the playhead and the notes for what you hear, not for what it’s computing. Some outputs are late enough to feel:

Bluetooth headphones and speakers add a delay you can hear, often around a fifth of a second. Playback stays in step with the screen, but playing along on a MIDI keyboard or through Monitor Input will lag. Use wired headphones or the built-in speakers to play or record.
An external display over AirPlay or a wireless link shows its picture late: its Display Delay keeps it with the sound (External displays).

When takes land late

A take recorded from the audio input can land a little after where you played it. Calibrate in the Audio & MIDI pane’s Audio tab measures this through the speakers and the microphone and sets the input’s Latency; you can also set it yourself, +0 to +100 ms. See Calibrating the latency.

MIDI notes can land late too, by the time a device takes to send them. Calibrate MIDI Latency in the Transport menu or the Transport pane › Record plays the click while you play along on the device, and sets its latency: see MIDI latency.