An often underestimated challenge for lecturers is a considerate use of their voice in teaching auditoriums. Even experienced lecturers are challenged by speaking in front of large classes or in new surroundings for the first time. Universities therefore often offer special voice trainings in which lecturers can be trained to use their voice correctly by a professional voice coach. Those trainings, however, often do not offer a realistic simulation of the lecturers' everyday teaching life. The project “ELLI” (Excellent Teaching and Learning in Engineering Sciences), funded by the federal ministry of education and research in Germany, aims at solving exactly this problem: It will give teachers the opportunity to practice their vocal capabilities in a special Mixed Reality Voice Lab. Within this lab, lecturers are able to participate in immersive voice trainings. Those trainings are adaptable to the lecturers' specific needs and environments and can therefore differ in terms of class size, stereoscopic vision and sonic interaction. The trainings are guided by professional vocal coaches. Currently, a first prototype of the Voice Lab that offers two different settings has been developed. The scenarios will be continuously improved based on user feedback and serve as a basis for the development of a wide range of adjustable settings. In order to generate the specific settings, that match the individual needs of the lecturers, real-life auditoriums have been acoustically measured by using specific professional microphones. The visual representation has been realized by using 360° cameras. In the long run, the immersive Mixed Reality Voice Lab will be deployable to other universities and contexts where it will offer lecturers the opportunity to practice their voice in environments that represent a realistic simulation of their actual teaching scenarios in terms of sound and vision. Additionally, lecturers will also be able to experience their own teaching in replay out of ...