Featuring handcrafted Mahongany earpieces made using an intricate curing process, Grado has been able to optimize the tonal quality. The RS1 uses dynamic transducers in an open-air configuration, the cups being open-backed. The result is a smooth, coherent sound with detailed dynamics. Frequency response ranges from 12-30 kHz and the drivers are matched to 0.05dB. Weighing 9oz, the headphones are an example of the wonder of mother nature with a gorgeous, honey-colored look.