Instruct: Classify Amazon reviews into positive or negative sentiment
Query: disappointed with Sennheiser, doesn't live up to its reputation

well, got the product and tried it, it has lots of background hissing sound, to get rid of the hissing sound, seems like I will have to tune it slightly off, but then you won't pick up the good sound reproduction if you do that. So if you tune it so that it pick up all the instrument, it tends to have background hissing sound. ya, if you turn up the volume, it will "suppressed" the hissing sound, but that is not a good headphone should do.