SE5WAY reference focus on bass...best armature drivers iem bass ever heard, very details and coherency sound, full bodies and mid not forward, smooth treble...very warm and dynamic sound signature
SE5WAY ultimate more balance sound, also warm, more transparent and details, also coherency with quality hit very deep bass, treble extension improved and smooth, mid not "V shape" anymore, very dynamic and 3D sound signature.
Agree with that, i owned K10 ciem which is more balance with warm sound signature, actually focus on mid and mid low more...different material really have different sound tuning characteristic...