Dry recording
Also known as: dry signal
A dry recording has no reverb, echo, or effects added, just the direct voice. It is what a voice clone wants as a sample, because reverb and processing baked into the audio get learned as part of the voice and are hard to remove later.
Why it matters
Anything baked into a recording becomes part of what a model learns. Record your voice in a boomy room and a clone learns the boom; add reverb before you clone and the clone reverberates on every line. Because those things are far easier to add later than to remove, a dry take keeps your options open.
In practice
Capture close, in a treated or soft space, with no reverb or effects on the way in. Add ambience and polish afterwards if you want them. For a cloning sample especially, dry and clean beats a take that already sounds finished.