Etymotic makes the world's most accurate noise-isolating headsets and earphones in all price categories. All low-cost earphones are made with dynamic (moving coil) drivers that have undesirable frequency response peaks and weak highs. Etymotic created a design that makes dynamic drivers sound like high-end drivers by inserting a proprietary acoustic side-branch to redistribute energy, smooth the peaks and compensate for weak highs. The result is the mc-series with best-in-class performance under $100.