Summary

The Etymotic 4S is a fantastic bargain in an earphone - some say better than the Sennheiser 650. Certainly clearer sounding with better inner detail. Much of their appeal is that they fit into the ears and isolate you from ambient noise - reducing background noise by about 24 DB. Ancillary equipment is most important as always. I use a Lehmann Black Cube Linear headphone amp to use with my iRiver IMP 400 portable CD player and the Etymotic 4S earphones, in a car. I also use the Etymotic 4S earphones and Lehmann amp it with my home CD player (a Nad 240). This is a very good CD player - best for the money, though the newer 242 offers better capacitors with some slight sound improvement. With this combo of Etymotic/Lehmann/NAD I heard inner detail, lightening fast transients, clearness of tones, and a natural timbre that was magical on a well recorded CD. The Lehman is the best headphone amp for under $1000 and competes favorably with any headphone amp regardles of price. The car set up requires the use of an inverter that puts out 1 amp or more of 110 Voltage on a continuous basis - I paid $20 for mine. The Etymotic 4S earphones reduce ambient noise by about 24 DB and thus are perfect for cars. They are small and can't be readily seen from outside the car in case it is illegal to use them. Using earphones is no more danger relative to listening to a good car system turned up to a satisfying sound level - you drive by sight and not sound in either case. The car system is really great - the best sound possible in a car. The homw system is even better though the sound quality of the iRiver is not far behind that of the NAD. The Lehmann is the heart of the system and is a truly remarkable discrete zero global feedback Class A output amp that serves also as a single input pre-amp. You could use the sytem above without the Lehmann amp if you use the Etymotic 4P instead of 4S earphones, since the 4Ps are more efficient and the external amp is less necessary. The sound will be fine though not as good as with the Lehmann.

Strength

As described.

Weakness

None significant.

Summary

I have to say, these earbuds are absolutely awesome. I am a mobile computer musician and I produce and engineer techno music and these earbuds are like a blessing. My soundcard that I'm using is a Echo Indigo on my Sony laptop. The Echo's pre-amp can drive these earbuds quite well. I wanted to get a pair of headphones that would deliver the most accurate reference for the mixes that I work with on with my laptop. They get the job done for producing music. After mixing with these and listening to the mixes I've made on Mackie HR824 studio monitors, the mixes are pretty close to what I was listening to when I originally mixed the music on my laptop. For my mobile studio, these headphones are great. I still use my HD600s occassionally. But, in my opinion, the low-end frequencies are more accurate and responsive with the ER4-S than the HD600s. It maybe because I am not using a good pre for my HD600s with my laptop, but I don't want to carry an extra pre-amp with me wherever I go. I've also own the ER6's which aren't bad. But, they can't compare to the ER4s. The ER4-S perform way more accurately than the ER6s in all frequency ranges. But the ER-6s are still very good in my opinion for listening to portable CD players. I give them 4 stars because they're still too expensive. Two hundred bucks is worth it to me, but it's still steep for earbuds.

Strength

Extremely accurate low-end Mid-range is excellent High quality manufacturing One-year warranty (from authorized dealers)

Weakness

High-end is a little teeny bit loud, but that's just to my ears.