Modular solutions for operation rooms made of glass and metal adversely affect the sound environment as the absorption of sound is non-existent. The requirement for Reverberation Time (T20) in operating rooms is according to Swedish Standard 25268 < 0.6 seconds. Modules without additional acoustic supplement are calculated to around 2.0 seconds.In our research the modular ceiling was replaced with an Absorption Class A ceiling according to ISO 11654. Both normal sized rooms (65m²) and the Hybrid room (105 m²) were treated with absorbents. To gain better understanding of the sound environment we also measured Speech Clarity (C50) in addition to reverberation time (T20). All acoustic requirements were fulfilled and this paper aim to evaluate how the staff perceives the sound environment in these rooms. Information will be obtained by questionnaires sent to 78 staff at Sundsvall hospital. The hospital performs 11000 procedures a year in 15 operating rooms. Procedures contains of common surgical, gynecological and orthopedic operations, as well as hernias, cancer, ear-nose-throat and fractures. Operating times varies from short to long and staff alternates within all procedures, the unit is open during evening and night for emergencies. Questionnaire consists of both multiple-choice and open questions.