18KHz. Intercom: Sustained, Built-in Microphone. Running Temperature level: -20 ～ 50 ℃. Dimensions: 283.1 * 224.3 * 269mm. Network Ceiling Speaker GEN-6211A03 Power Supply: DC 24V/1A or POE. Communication Procedures: TCP/IP, UDP, SIP, ONVIF. Signal-to-Noise Proportion: > 80dB. Regularity Feedback: 100Hz https://power-line70900.targetblogs.com/30517617/the-ultimate-guide-to-setting-up-your-ip-pa-system-efficiently