Opties TE27 MK09 Cardioide microfoon 123dB SPL Bestel MI04 Omnidirectional microfoon Bestel SL63 Post processing software Bestel SL64 Maximum length sequence software Bestel SL65 Precision Equalization software Bestel SL66 Polar Energy-time curves software Bestel SL67 Polar software Bestel SL68 Noise level Analyse software Bestel SL51 Hardware kit room referentie Bestel