[Tyson]

Well, this has to be about the coolest purchase I've made in a while - Got a pair of Etymotics ER-4P canalphones in earlier this week, been running them in all week.  These things are pretty amazing, and are amazingly small.  The look almost like earbuds when you have them in (very discreet), but they have amazingly good sound, in many respects better than my Sennheiser HD600's, the detail, transparency, clarity, and dynamics are all better.  The 600's only better the Ety's in 2 areas, they have better bass slam (ie a more physical presentation of the bass, since bass on the Ety's is more heard than felt), and the 600's image "in your head" to a lesser extent than the Ety's.  Other than that, the 4P's pretty much kick ass.

With these headphones/canalphones, you can choose either the foam tips or the silicon tips.  The foam tips don't sound as good, but on the other hand the silicon tips are a bit difficult to get put in just right.  But once you do get them in just right, the transparency very much rivals the best ribbon/electrostatic speakers.  Very nice indeed.

I haven't even mentioned the isolation yet - when you put these things in, the outside world tends to just go away sonically.  20-25 db of isolation.  Conversations, fans, keyboard strokes, babies crying, all tend to just go away, even with no music playing.  Since you are now in a quiet environment (it's like wearing ear plugs), you don't have to blast the volume to drown out other sounds, which is much better for your hearing long term.

The only complaint I have at all is that there is not much power to deep bass.  In this respect they are like listening to a world class bookshelf speaker, where as the HD600's give more of a full range tower type sound.  The bass that is there (down to the mid bass) on the 4P's is nice and full, it just doesn't do real deep bass with any power.

Anyway, all of you audiophools that have to travel or work in a noisy environment, the 4P's get a very big thumbs up, especially given their amazingly small size.  They come with a small pouch that zips up and fits very easily in to a shirt front pocket, or in a bag or briefcase.  Put them with an Ipod or quality discman and you've got great sound on the go.

[TheeeChosenOne]

I agree with youy on all counts.  

Very good earphones.  I have a pair myself.  

I use them for my 20gb mp3 playa on planes, beaches, walks, etc.  Very good with shutting the world out.

On planes they're a godsend since they block out all the noise.  Load a couple of audio books to the mp3 player and you're set.......Of course, a Gameboy Advance with sports titles also helps pass the time on planes.

[shokunin]

I've had my pair of 4s's for nearly 7 years now and they are absolutely fantastic on airplanes.  They've also have held up well over those years, never failing even though they've seen the roughest treatment possible.  My only complaint is the microphonic cord, but other than that they  

[DrDave]

I would also reccommend the ER6's.  They are cheaper but do a remarkable job.  They are far superior to 2 pairs of active noise cancelling phones I've had for travelling. javascript:emoticon(':lol:')
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[Tyson]

I have the ER 6's too, I bought them first as a matter of fact, but I have to say I think the ER 4P's are a much better buy, mainly because they sound much better, but also because they are a lot easier to get a good fit/seal in your ear.  Still, the ER-6's are far, far better than any ear bud type headphone I've ever heard.  Most earbuds sound like mass market crap speakers sold at best buy or circuit city.  The ER-6's sound a lot like decent quality bookshelf speakers like the Paradigm Studio 20's (good clarity and resolution, a little light in the bass, a little bright and slightly grainy), and the ER 4P's sound like excellent quality bookshelf speakers (ie, like VMPS 626Rs, utterly smooth, highly resolving, strong response down to the mid bass.)  Just my $.02

[Tyson]

Just an update, I bought a converter cable for my 4P's which convert's them to the 4S and the improvement was not small.  I resisted trying the 4S initially because everyone said that the 4S had less bass, but this is NOT the case - what the 4S has less of is mid/upper bass bloat.  The 4S is actually a bit more percussive in it's presentation of bass because you don't have that slight mid bass fuzz covering up the impact of drums or bass guitars or other bass instruments.  And bass detail improves quite a bit.  

In fact detail across the entire spectrum increases signifignantly, and the highs are even smoother.  Seperation between instruments and different melodic lines is the absolute best I have ever heard from a pair of headphones.  Room ambiance and other spatial ques are outstanding.  As good as the 4P's were, the 4S' are clearly superior.  At this point I would say the 4S is the best headphone I've ever heard, handily bumping the Sennheiser HD-600's w/Cardas cable out of the top spot.  And it doesn't hurt that the 4S' are a LOT easier to drive than the 600's

[Val]

Agree with Tyson and TheChosenOne on all points too, especially on the ER4S, flat as a guitar string, neutral and perfect. Sad that there is so little sense of low bass because they don't move practically any air, but I checked them with two Stereophile test CDs and they go down to 20Hz flat.