The Stichting Omroep Muziek (SOM) includes the Groot Omroepkoor (GOK) and the Radio Philharmonisch Orkest (RFO) and is the production house for live music for the public broadcasting company with approximately 230 employees. Within the framework of the Living Music remit, the SOM produces two large symphonic series for NPO Radio 4, commissioned by and in cooperation with NTR and AVROTROS: the NTR Saturday Matinee and the AVROTROS Friday Concert.