MartinLogan - Classic Dual 8" Passive 2-Way Floor Speaker (Each) - Dark cherry - Open Box - Excellent

Hello. Thank you for your question and for your interest in our products. The speaker needs to be powered with an AC adaptor and needs to be powered with an amp/AV receiver. The AC power supply is used to charge the electrostatic panel, but it still needs power from the amp/AV receiver. We hope this helps and please let us know if you have any other questions. Thank you for your support, and we hope you have a wonderful day.

Thank you for your question, and we hope all is well. Yes, this model is an electrostatic speaker using advanced MicroPerf stator technology, which allows for almost twice the exposed electrostatic diaphragm surface as a traditional electrostatic panel of the same size. The Classic ESL 9 is also part of our Masterpiece series using our new ultra-rigid AirFrame Blade design, which enhances imaging, low-level sonic detail, accuracy, and speaker efficiency. We hope this helps and thank you for your interest in our products.

The sensitivity of the MartinLogan Classic ESL 9 floorstanding speaker is 90 decibels.

The minimum frequency response of the speaker is 34 hertz.

The product weighs 78 pounds. It is 59.8 inches high, 25.4 inches deep, and 10.4 inches wide.