Second trial different opinion. Thins time I used my (awesome) Dethronray DTR1 DAP which drives these like a charm in high gain. Barely at half the volume, and everything sounds well controlled. Recommended to Z1R users for on the go. This tells me the first I had try at the Sony store was defective or that the WM1Z is not powerful enough. The Z1R sounds great. Space, bass, resolution, everything. Such air and openness, never seen that in an IEM. But this I knew. My surprise are the mids. They are indeed a bit thin but only slightly so, so I guess this is back on the list. A bit huge though. Still very comfortable but huge.