18KHz. Intercom: Sustained, Built-in Microphone. Running Temperature: -20 ～ 50 ℃. Dimensions: 283.1 * 224.3 * 269mm. Network Ceiling Audio Speaker GEN-6211A03 Power Supply: DC 24V/1A or POE. Communication Procedures: TCP/IP, UDP, SIP, ONVIF. Signal-to-Noise Proportion: > 80dB. Regularity Response: 100Hz https://andrennfqe.activoblog.com/30761651/choosing-the-right-ip-speaker-trick-includes-to-take-into-consideration