This study has investigated to what extent musicians adjust their source levels to different music rehearsal rooms. In the experiment, six amateur musicians were to perform the same song i four different rehearsal rooms, by first singing, then by playing guitar and last by combining singing with guitar playing. All sound sources were recorded and analyzed. The results shows that the average musician adjusts his source levels to the rehearsal room and that most of the adjustments are made in the guitar playing. Looking at the individual musician there are some that do not show any signs as to being affected by the rooms, and there are some that shows clear signs of being affected by the rehearsal room. The result also shows that the musicians are affected differently by different acoustic parameters, whereas the strength shows the least correlation and reverberation time shows the most correlation to the adjustment made by the average musician.