Abstract: The method of using optimized wall section had been improved. Widths and depths of wells in wall were optimized synchronously to improve low frequency response in a room. By calculating frequency response from 60 Hz to 120 Hz, when source located at different locations in a room, robustness of an optimized room had been analyzed and compared with the results in an original room. The results showed that after optimization design, average of the squared root deviation of sound frequency response (SRD) reduced from 9.66 dB in a 5×4.65×2.68 m³ room to 6.17 dB; average of the maximum deviation of sound frequency response (MD) reduced from 41.27 dB to 17.42 dB; standard deviation of SRD reduced 44.8% and standard deviation of MD reduced 63.9%. These results demonstrated that optimized wall not only had effect on improving frequency response, but also had effect on reducing frequency response sensitivity to sound source location. Therefore, it was useful to use optimized wall section to improve robustness of low frequency response.