Ableton limiter lookahead

1. What does lookahead do on a limiter?
2. Does Ableton have a built in limiter?

What does lookahead do on a limiter?

Look-ahead allows the limiter to do level detection on a signal that is advanced relative to the audio path. This gives the detector time to react to an incoming transient. Once the signal appears in the look-ahead buffer, the detected level must then converge to the incoming level within the look-ahead window.

Does Ableton have a built in limiter?

With the right settings, a compressor can also double as a limiter, but in Ableton Live we have compressors and a limiters as separate devices, which keeps things a bit more immediate. Unlike most audio effects, a compressor doesn't have a characteristic sound.