It is a bit difficult to know what exactly is meant without more context. "Lauteinsatz" is in phonetics/speech therapy/phonology used as German term for "voice onset"

Have a look at.

http://ling.uni-konstanz.de/pages/einfuehrung/02.pdf

(pg. 3)

"Voice onset" is often used as part of the phrase "voice onset time" (sometimes called "Stimmeinschwingzeit" in German), i.e., the period of time between (the acoustic counterpart of) an occlusion in the oral cavity (e.g., in the case of plosives and fricatives) and the time, when the voice starts (the "voice onset"/"Lauteinsatz"). So the voice onset time is the period of time before the voice onset ("Lauteinsatz") sets in.