Pros: Excellent Detail, Flat Response, Great Isolation
Cons: ER 4S needs a powerful amp, it's hard to fit them in ear canal
I'm surprised that no review has been written about those gems! The ER 4P/S is one of the best IEMs in the market value wise. They are made to last, they isolate like no other IEM and they have a unique flat frequency response which can be easily adjusted if you have a good equalizer or an integrated amp. The ER S will sound best when used with a powerful amp, it will provide an amazing sound stage and wonderful imaging of instruments and players. They can provide life like details of the recording including movements, coughs, breathing and pages turned over depicted with extreme clarity. Highly recommended.