This paper presents a method to cancel the echoes generated by reflections in a room. The starting point is the full-band adaptive system identification method, where the unknown system is the room, providing several reflections of the sound. A sub-band filtering method is proposed and all the aspects regarding the filter banks, the structure, the number of sub-bands and the order of the required filters are analyzed. The performance is studied with respect to the provided error and the echo return loss enhancement. The asymmetric structure sub-band filtering offers a better performance than the full-band implementation. Increasing the number of sub-bands will also enhance the performance of the system.