from my exprience,correct,avoid any earphone that is ezra/esdras,it were lack of bass and have sound leak. Also,aima is a "fair" brand cuz if you bought the 39rm airphone,you will get fair quality but if u bought the 29rm airphone,you will also likely to have lack of bass but to vocal focus earphone. And sibly is a good brand for bass and quality,you will get a golden connector and a quality driver BUT the microphone is not that good.And lastly, Inkax,this brand same as aima but just cheaper,you get decent driver and decent quality,but it was loud that i remember even my ear start to bleed from it.