The SE535 utilizes a dedicated tweeter and dual woofers to deliver spacious sound with rich bass. The color models (Bronze and Red) come with two new connectivity options -- an included Bluetooth cable for wireless convenience and a universal communication cable (compatible with both Apple and Android). If you notice a change in sound quality, remove the sleeve and check the nozzle of your earphone. If nozzle is blocked, clear obstruction by using wire loop end of cleaning tool.If no obstruction is found or if sound quality does not improve, replace the sleeve with a new sleeve.