Decora® Strauss Transformer-Free Impedance Matched Volume Control, White. Leviton’s Decora Strauss Transformer-Free and Transformer- Free Impedance Matching Volume Controls, combined with premium installed speakers, can be used to design a no compromise installed multi-room entertainment system that delivers the best reproduction possible from today’s ultra-wide bandwidth digital sources. In multi-room distributed audio systems, the source of undesirable speaker coloration (usually perceived as a “muffled-inch sound) is often the volume control itself, because the audio transformers (AKA: auto formers) used in conventional controls can actually filter the bass and treble frequencies. The Decora Strauss Transformer-Free Volume Controls use audio-grade Cermetile resistors to change volume levels while leaving the audio signal unaffected, resulting in ruler-flat frequency response across the entire audible frequency range. Moreover, the Decora Strauss Transformer-Free Volume Controls eliminate the problem of “saturation-inch associated with conventional volume controls with their ability to instantaneously handle the full peak output power of any consumer-grade amplifier on the market today. The award-winning Decora Strauss Transformer-Free Matching Controls are available in two versions: regular and Impedance-Matching.