100 ? Owch. If you want a
drastic change, get some Grado SR-125. They have like an opposite sound signature to sennheiser
Sennheisers are for bassy, slow, and classical music.
Grado are for Rock, Punk, Metal, anything with punch and fast pace. Whilst they don't have as much bass as sennheisers, it's quicker more toned and greater impact.
edit:
Here are some Sennheiser HD600's compared to SR125 (all senns have similar sound signature)
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Notice the rather large peak around 10khz on the SR125 ? Some find it peirceing, but when i had to SR225's (altho they are less bright than the 125, but still considered bright) i didn't find them peircing at all. But that 10khz peak makes rock music awesome.
edit:
Okay, the link just takes you too the graph. But take a look at sr215 v hd600