I already own Sennheiser CX300 and my friend owns Sennheiser CX400. The biggest trouble with cx300 is that, although it may have good sound quality, it has no bass! While, cx400 offers tremendous bass that a earphone can have. Since, I am looking for a headphone with decent sound quality and natural bass, as was in Sennheiser CX400 and in Koss Portapro, my expectations with this headphone is high. I love bass, so please make me aware of its bass quality. Thank you in advance.