There is a chapter at the back of the manual that almost nobody reads, and it settles a lot of arguments. Ableton documents precisely which operations pass audio through untouched and which change it.
Neutral: the signal comes out identical
- Rendering without dither, at the same sample rate, with no transposition.
- Unstretched playback in Beats, Tones, Texture and Re-Pitch warp modes.
- Summing at a single mix point. Live's mixer does not colour anything.
- Recording external signals at or above the converter's bit depth.
- Recording internal sources at 32 bit.
- Freezing tracks. A frozen track is bit-identical to the unfrozen one.
- Bypassed effects, routing, and splitting clips.
That list is worth internalising. Freezing does not degrade anything. The mixer does not have a sound. Routing costs you nothing.
Not neutral: these do change the audio
- Complex and Complex Pro warp modes. They are resynthesis; they cannot be transparent. The other warp modes are, when not stretching.
- Sample rate conversion and transposition.
- Volume automation — because it is doing arithmetic on the samples.
- Dithering, obviously, and only ever once, at the very end.
- Recording below the converter's bit depth, or internal sources below 32 bit.
- Consolidate, clip fades, panning and grooves.
What to do with this
Three practical conclusions.
- Freeze without guilt. It is documented as bit-identical.
- Dither once. If you dither a mix and then dither the master, you have added noise twice. Set the render to no dither unless it is the final file.
- Choose warp modes deliberately. If a clip is at project tempo and does not need stretching, Beats mode is transparent and Complex Pro is not. Do not leave everything on Complex Pro because it sounds better on the one clip that needed it.
The manual's own conclusion is worth repeating: the places you can lose quality in Live are few, documented, and mostly avoidable.