M&K Sound Frameless Architectural IW-950 – The competitively priced IW-950 features the company’s own drivers and design that is intended to maintain structurally sound cabinets the result with the speaker producing neutral sound with wide images. The 90dB efficient speaker has a rated frequency response of 80Hz to 20kHz, and the speaker incorporates a pair of 5.25-inch midrange drivers and 1-inch soft-dome tweeter.