Been listening to a set of MDR-7550s that came with a 7N-OFC EX1000 cable. I've only had the Phonak PFE before this so moving to a dynamic driver IEM is interesting.
One of the previous owners of my 7550s said that the silver EX1000 cable made the sound smoother and warmer and tamed the treble while in this link, http://www.head-fi.org/t/559335/quick-impression-sony-mdr-7550/285#post_8586292, the cable supposedly made the 7550's treble to be more similar to the EX1000.
Listening to them over the PFEs, I noticed stronger bass quantity, slight amount of bass quality, a much bigger sound stage, and more details in my songs. As for the treble, I feel there is less treble than the PFEs and it's not as energetic nor as present in comparison to the other instruments, but it is there.
Maybe it's because I haven't listened to dynamic IEMs before and am not accustomed to this level of bass quantity, but I've been trying to figure out which bands to EQ to get a bit more treble and airiness out of the 7550s to match the EX1000s more closely. So far I've just added +2dB at the 5.5Khz and 9Khz bands. It definitely helps but I think it actually makes vocals a bit more forward since they seem louder. It makes the vocals feel like the person took a step or two forward. I'm also trying +1dB or 1.5dB for both bands instead of +2dB to strike a good balance between everything.
Overall, I think it contrasts my PFEs really well since those were more lean in bass quantity, had a more intimate sound stage, and brighter treble.