High Quality Sound Performance Herdio HCS818 in Ceiling Speakers with 2x Speakers, Frequency Response is 50Hz-20k Hz with 89db at 8 Ohms can deliver crystal fantastic sound playback easily streamed from your Bluetooth Amplifier compatible smartphone, tablet or Alexa. (Not include Bluetooth amplifier) 2-Way Home Speaker System The in-ceiling speaker combined with dual high excursion 6.5 inch poly woofers and a 1 inch soft dome tweeter. Both the woofer (for bass frequencies) and the tweeter (for high-end frequencies) work together to provide excellent integrated sound details with a frequency response of 50Hz 20k Hz