Well, I would say I've listened to some pretty heavy rock on the Lores with quite a bit of pleasure. My first night's listening session was with a live Ween concert at concert levels, and I was FULLY rocking out on it. Some of my heaviest bass music is probably my Soul Coughing albums. They have some really intense synthesized bass going on, and especially on Ruby Vroom, it's really high quality as well (upright bass for that stuff). I would never say the Lores were "confused" on any of this material in the bass region.
Your biggest risk with heavy rock, in my experience, is that it's been recorded/mixed using "modern" techniques that quash all the dynamics. If this is the case, the Lores will sound loud but compressed, as that's exactly what the recording is offering. Sometimes that's listenable, other times not. YMMV I could see strong potential for heavy metal to be unlistenable if it was recorded/mixed badly - think modern Metallica. On the other hand, some more underground heavy metal is actually extremely very technically demanding, and I bet some of those recordings paid attention to quality. Not being a heavy metal buff, I can't suggest a good example there.
Bottom line, the Lores will completely rock if the source material and amplification is up to the challenge.
Your biggest risk with heavy rock, in my experience, is that it's been recorded/mixed using "modern" techniques that quash all the dynamics. If this is the case, the Lores will sound loud but compressed, as that's exactly what the recording is offering. Sometimes that's listenable, other times not. YMMV I could see strong potential for heavy metal to be unlistenable if it was recorded/mixed badly - think modern Metallica. On the other hand, some more underground heavy metal is actually extremely very technically demanding, and I bet some of those recordings paid attention to quality. Not being a heavy metal buff, I can't suggest a good example there.
Bottom line, the Lores will completely rock if the source material and amplification is up to the challenge.